WO2005104610A1 - 共鳴周波数検出方法、共鳴周波数選択方法、および、共鳴周波数検出装置 - Google Patents
共鳴周波数検出方法、共鳴周波数選択方法、および、共鳴周波数検出装置 Download PDFInfo
- Publication number
- WO2005104610A1 WO2005104610A1 PCT/JP2005/007868 JP2005007868W WO2005104610A1 WO 2005104610 A1 WO2005104610 A1 WO 2005104610A1 JP 2005007868 W JP2005007868 W JP 2005007868W WO 2005104610 A1 WO2005104610 A1 WO 2005104610A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- frequency
- signal
- characteristic
- microphone
- resonance
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R29/00—Monitoring arrangements; Testing arrangements
- H04R29/007—Monitoring arrangements; Testing arrangements for public address systems
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R27/00—Public address systems
Definitions
- Resonance frequency detection method Resonance frequency detection method, resonance frequency selection method, and resonance frequency detection device
- the invention relates to a resonance frequency detection method for detecting a resonance frequency in a resonance space, a device thereof, and among the detected resonance frequencies, a dip filter is set as a center frequency of the dip.
- the present invention relates to a resonance frequency selection method for selecting a power frequency.
- a resonance frequency in a resonance space it is necessary to detect a resonance frequency in a resonance space.
- sound equipment such as speakers is installed in a hall or gymnasium, and loudspeakers are radiated by the speaker
- the sound from the speakers may be lost due to the resonance frequency of this space (the loudspeaker space in which the sound equipment is arranged).
- the music and voice of the music can be heard. That is, if a loud sound from a speaker contains many components of the resonance frequency, resonance occurs at the frequency of this component in the loud sound space.
- the resonance sounds like "Won Won ⁇ ⁇ ⁇ ⁇ " or "fan fan ⁇ ⁇ ⁇ ⁇ ". This resonance makes it difficult to hear music and speech from the speaker, rather than the sound that is supposed to radiate from the speaker.
- a dip filter or the like that detects a resonance frequency in the loudspeaker space and attenuates the component of the resonance frequency in a sound facility may be provided upstream of the speaker. Then, resonance is less likely to occur in this loudspeaker space, and music and speech from speakers can be easily heard.
- the resonance frequency of the sound space In order to determine the frequency characteristics of the dip filter, first, the resonance frequency of the sound space must be detected.
- the resonance frequency is a frequency determined by the characteristics of the resonance space
- the feedback frequency is a frequency determined by the configuration of the feedback loop including the electroacoustic system.
- An object of the present invention is to provide a resonance frequency detection method and an apparatus thereof that can accurately detect a resonance frequency without requiring experience or skill.
- Another object of the present invention is to provide a resonance frequency selection method capable of objectively selecting, from among a plurality of detected resonance frequencies, a center frequency of a dip in a force dip filter to be set. I do.
- the resonance frequency detecting method includes a basic step of measuring a basic amplitude frequency characteristic, a first step of measuring a first amplitude frequency characteristic, and a second amplitude frequency characteristic. And a second step of measuring, wherein the basic amplitude frequency characteristic is obtained by loudspeaking a predetermined measurement signal from a speaker arranged in the resonance space and receiving the sound by a microphone arranged in the resonance space.
- the first amplitude frequency characteristic is obtained by loudspeaking the measurement signal and the first delay signal obtained by delaying the output signal of the microphone by a first delay time of 0 or more from the speaker.
- the second amplitude frequency characteristic is obtained by receiving the measurement signal and the output signal of the microphone from the speaker with a second delay time of 0 or more.
- the second delay signal is an amplitude frequency characteristic obtained by loudspeaking the received second delay signal and receiving the sound by the microphone
- the second delay time is a delay time different from the first delay time
- the basic amplitude Based on the wave number characteristic, the first amplitude frequency characteristic, and the second amplitude frequency characteristic, a resonance frequency of the resonance space is detected based on 1.
- the measurement signal may be delayed with the output signal of the microphone and amplified from the speaker, or may be amplified from the speaker without delay.
- a resonance frequency detecting apparatus includes a sound source means, a signal switching means, and a measuring means, wherein the sound source means generates a signal for measurement,
- the switching means is capable of inputting a measurement signal from the sound source means and an output signal from the microphone, and the signal switching means outputs a state of the measurement signal so that the measurement signal is amplified by a speaker.
- the time is different from the first delay time.
- the measuring means is capable of measuring the output signal power amplitude frequency characteristic of the microphone, and the measuring means measures the basic amplitude frequency characteristic measured when the state of the signal switching means is set to the basic state.
- the resonance frequency is detected based on a comparison with the sometimes measured second amplitude frequency characteristic.
- the measurement signal may be delayed from the loudspeaker together with the output signal of the microphone, or may be loudspeaked without delay.
- the first delay time or the second delay time may be zero.
- another resonance frequency detecting method includes a basic step of measuring a basic amplitude frequency characteristic, a first step of measuring a first amplitude frequency characteristic, and a second step of measuring a first amplitude frequency characteristic.
- a second step of measuring the amplitude frequency characteristic wherein the basic amplitude frequency characteristic is obtained by loudspeaking a predetermined measurement signal from a speaker arranged in the resonance space and receiving the sound by a microphone arranged in the resonance space.
- Amplitude frequency characteristics obtained by The first amplitude frequency characteristic is an amplitude frequency characteristic obtained by loudspeaking the measurement signal and the output signal of the microphone from the speaker and receiving the sound by the microphone, and the second amplitude frequency characteristic.
- a resonance frequency of the resonance space is detected based on a frequency characteristic, the first amplitude frequency characteristic, and the second amplitude frequency characteristic.
- the measurement signal may be inverted in phase together with the output signal of the microphone and amplified from the speaker, or may be amplified from the speaker without inverting the phase.
- another resonance frequency detecting apparatus includes a sound source means, a signal switching means, and a measuring means, wherein the sound source means generates a measurement signal
- the signal switching means is capable of inputting a measurement signal from the sound source means and an output signal from a microphone, and the signal switching means outputs the state so that the measurement signal is amplified by a speaker.
- a basic state a first state in which the measurement signal and the output signal of the microphone are output to make the speaker louder, a phase in which the measurement signal and the output signal of the microphone are inverted in phase.
- the inverted signal can be switched to a second state in which the inverted signal is output by the speaker, and the measuring means can measure the amplitude frequency characteristic from the output signal of the microphone; Comparison between the basic amplitude frequency characteristic measured when the state of the switching means is set to the basic state and the first amplitude frequency characteristic measured when the state of the signal switching means is set to the first state. A resonance frequency is detected based on a comparison between the basic amplitude frequency characteristic and a second amplitude frequency characteristic measured when the state of the signal switching means is set to the second state.
- the phase of the measurement signal may be inverted with the output signal of the microphone, and may be amplified from the speaker, or may be amplified from the speaker without inverting the phase.
- a peak point having a larger amplitude in the first amplitude frequency characteristic than in the basic amplitude frequency characteristic is obtained from a difference between the basic amplitude frequency characteristic and the first amplitude frequency characteristic.
- Is detected as a first group frequency and the difference between the basic amplitude frequency characteristic and the second amplitude frequency characteristic is used to determine the peak point at which the second amplitude frequency characteristic has a larger amplitude than the basic amplitude frequency characteristic.
- Is detected as the second group frequency, and the first group A frequency commonly included in the frequency and the second group frequency may be detected as a resonance frequency.
- a resonance frequency selection method detects a plurality of resonance frequencies by the above-described resonance frequency detection method, and selects a dip from among the plurality of detected resonance frequencies.
- the center frequency of the dip to be set in the filter is selected from the first amplitude frequency characteristic or the second amplitude frequency characteristic having a large amplitude level.
- the center frequency of the dip to be set in the dip filter is obtained by subtracting the basic amplitude frequency characteristic from the first amplitude frequency characteristic or the second amplitude frequency characteristic.
- a power having a large amplitude level in the amplitude frequency characteristic may be preferentially selected.
- yet another resonance frequency detection method provides a method in which a reference frequency signal that is maintained for a predetermined time is louder from a speaker arranged in a resonance space. And an attenuation characteristic measuring step of measuring an attenuation characteristic of an output signal of the microphone, and detecting a resonance frequency of the resonance space based on the attenuation characteristic.
- the reference frequency signal is a sine wave signal of a specific frequency or a signal having a component within a predetermined frequency width centered on the specific frequency.
- still another resonance frequency detecting apparatus includes a sound source means and a measuring means, and the sound source means generates and outputs a measurement signal.
- the measurement signal is a reference frequency signal that lasts for a predetermined time, and the reference frequency signal is a sine wave signal of a specific frequency or a signal having a component within a predetermined frequency range around the specific frequency.
- the measuring means is capable of inputting an output signal of a microphone, and the measuring means measures an attenuation characteristic of the output signal of the microphone, and detects a resonance frequency based on the attenuation characteristic.
- still another resonance frequency detecting method provides a reference frequency signal that is maintained for a predetermined time from a speaker arranged in a resonance space and a resonance frequency detection method that is arranged in the resonance space.
- Attenuation characteristic measuring means for amplifying the output signal of the microphone, receiving the sound by the microphone, and measuring the attenuation characteristic of the output signal of the microphone.
- a resonance frequency detecting method for detecting a resonance frequency of the resonance space based on the attenuation characteristic, wherein the reference frequency signal is a sine wave signal of a specific frequency or a predetermined frequency centered on a specific frequency. This is a signal having a component within the frequency width.
- still another resonance frequency detecting apparatus includes a sound source means, a signal output means, and a measuring means, and the sound source means generates a measurement signal.
- the measurement signal is a reference frequency signal that lasts for a predetermined time, and the reference frequency signal is a sine wave signal of a specific frequency or a signal having a component within a predetermined frequency width centered on the specific frequency.
- the signal output means is capable of inputting a measurement signal from the sound source means and an output signal of the microphone, and the signal output means is for loudspeaking the measurement signal and the output signal of the microphone with a speaker.
- the measuring means can input the output signal of the microphone, the measuring means measures the attenuation characteristic of the output signal of the microphone, and determines the resonance frequency based on the attenuation characteristic. Detecting the number.
- a specific frequency of the reference frequency signal may be determined to be the resonance frequency.
- still another resonance frequency detecting method is a method of detecting a reference frequency signal intermittently repeated a plurality of times from a speaker arranged in a resonance space. And a delay signal obtained by delaying the output signal of the microphone arranged in the microphone with a delay time of 0 or more, receiving the sound by the microphone, and measuring the attenuation characteristic of the output signal of the microphone.
- a resonance frequency detection method for detecting a resonance frequency of the resonance space based on the attenuation characteristic, wherein the delay time changes in synchronization with intermittent repetition of the reference frequency signal The reference frequency signal is a sine wave signal of a specific frequency or a signal having a component within a predetermined frequency width around the specific frequency.
- the reference frequency signal may be delayed along with the output signal of the microphone and amplified from the speaker, or may be amplified from the speaker without delay.
- the output device includes a sound source means, a signal output means, and a measurement means, wherein the sound source means generates a measurement signal, and the measurement signal is a reference frequency signal intermittently repeated a plurality of times;
- the reference frequency signal is a sine wave signal of a specific frequency or a signal having a component within a predetermined frequency range centered on the specific frequency.
- the signal output means includes a measurement signal from the sound source means and an output of a microphone.
- a signal, and the signal output means is capable of outputting the measurement signal and a delay signal obtained by delaying the output signal of the microphone by a delay time of 0 or more to cause a speaker to loudspeak;
- the signal output means changes the delay time in synchronization with the intermittent repetition of the reference frequency signal, the measuring means can input an output signal of the microphone, and the measuring means An attenuation characteristic of the output signal is measured, and a resonance frequency is detected based on the attenuation characteristic.
- the reference frequency signal may be delayed together with the output signal of the microphone and amplified from the speaker, or may be amplified from the speaker without delay.
- the specific frequency of the reference frequency signal may not be determined as the resonance frequency.
- still another resonance frequency detecting method is a method of detecting a reference frequency signal intermittently repeated a plurality of times from a speaker arranged in a resonance space. Or a reference frequency signal intermittently repeated a plurality of times, and a phase obtained by inverting the phase of the output signal of the microphone arranged in the resonance space.
- a resonance frequency detecting method for detecting a resonance frequency of a sound space wherein a loudspeaker state changes from the first loudspeaker state to the second loudspeaker state in synchronization with intermittent repetition of the reference frequency signal.
- the reference frequency signal is a sine wave signal of a specific frequency or a signal having a component within a predetermined frequency width centered on the specific frequency. is there.
- the reference frequency signal is phase inverted with the microphone output signal Then, the sound may be loudspeaked from the speaker, or may be loudspeaked from the speaker without inverting the phase.
- still another resonance frequency detecting apparatus includes a sound source means, a signal output means, and a measuring means, and the sound source means generates a measurement signal.
- the measurement signal is a reference frequency signal that is intermittently repeated a plurality of times, and the reference frequency signal is a sine wave signal of a specific frequency or a signal having a component within a predetermined frequency width around the specific frequency.
- the signal output means is capable of inputting a measurement signal from the sound source means and an output signal of the microphone, and the signal output means indicates the state of the measurement signal and the output of the microphone.
- a first output state in which the signal is output to make the speaker loudspeaker, or the measurement signal and a phase inverted signal obtained by inverting the phase of the output signal of the microphone are output in order to make the speaker loudspeaker.
- the second output state can be selectively set, and the state of the signal output means can be changed from the first output state to the second output state in synchronization with the intermittent repetition of the reference frequency signal. Or the state is changed from the second output state to the first output state, wherein the measuring means is capable of inputting an output signal of the microphone, and the measuring means is capable of changing an attenuation characteristic of the output signal of the microphone. Measure and detect the resonance frequency based on the attenuation characteristics.
- the reference frequency signal may be inverted in phase along with the output signal of the microphone and amplified from the speaker, or may be amplified from the speaker without phase inversion.
- the attenuation characteristic changes due to the change in the loudspeaker state.
- the specific frequency of the reference frequency signal may not be determined as the resonance frequency, and in the above-described apparatus, the measuring unit may have the attenuation characteristic due to a change in the state of the signal output unit. It is determined whether or not the force changes, and when it is determined that the attenuation characteristic changes due to a change in the state of the signal output means, the specific frequency of the reference frequency signal is not determined to be the resonance frequency.
- the measurement signal may be any signal as long as it is a signal suitable for measuring the amplitude frequency characteristic.
- a sine wave sweep signal with a component within a predetermined frequency width It may be a noise signal whose frequency is swept or pink noise.
- the measurement of the attenuation characteristics may be repeated a plurality of times while changing the specific frequency of the reference frequency signal.
- the present invention it is possible to accurately detect a resonance frequency without requiring experience or skill, and to appropriately select a frequency to be set as a center frequency of a dip in a dip filter.
- FIG. 1 is a schematic configuration diagram of an acoustic system installed in a sound space (for example, a concert hall or a gymnasium).
- a sound space for example, a concert hall or a gymnasium.
- FIG. 2 is a schematic block diagram of a system for measuring amplitude frequency characteristics in a public space (for example, a concert hall or a gymnasium).
- FIG. 3 is a schematic block diagram of a system for measuring amplitude frequency characteristics in a loudspeaker space.
- FIG. 4 is a characteristic diagram schematically showing amplitude frequency characteristics of a loudspeaker space measured by the system of FIG. 2 and amplitude frequency characteristics of a loudspeaker space measured by the system of FIG. 3.
- FIG. 5 is a frequency characteristic diagram obtained by subtracting the characteristic of the real curve Ca from the characteristic of the broken curve Cb in FIG.
- FIG. 6 is a schematic block diagram of a system for measuring amplitude frequency characteristics in a loudspeaker space.
- FIG. 7 is a characteristic diagram schematically showing amplitude frequency characteristics of a loudspeaker space measured by the system of FIG. 2 and amplitude frequency characteristics of a loudspeaker space measured by the system of FIG. 6;
- FIG. 8 is a frequency characteristic diagram obtained by subtracting the characteristic of the real curve Ca from the characteristic of the broken curve Cc in FIG. 7.
- FIG. 9 is a schematic block diagram of a system including a detection device as one embodiment of a resonance frequency detection device according to the present invention.
- FIG. 10 shows an example of a configuration that can be employed as a delay device in the detection device of FIG. FIG.
- FIG. 11 is a schematic block diagram of a system for measuring amplitude frequency characteristics in a loudspeaker space.
- FIG. 12 is a characteristic diagram schematically showing amplitude frequency characteristics of a loudspeaker space measured by the system of FIG. 2 and amplitude frequency characteristics of a loudspeaker space measured by the system of FIG. 11;
- FIG. 13 is a frequency characteristic diagram obtained by subtracting the characteristic force of the real curve Ca from the characteristic force of the broken curve Ce in FIG.
- FIG. 14 is a schematic block diagram of a system including a detection device as one embodiment of a resonance frequency detection device according to the present invention.
- FIG. 15 is a schematic block diagram of a system for detecting a resonance frequency in a sound space (for example, a concert hall or a gymnasium).
- a sound space for example, a concert hall or a gymnasium.
- FIG. 16 is a diagram showing signal levels of measurement signals on a time axis.
- FIG. 17 is a diagram showing a sound pressure level measured by a microphone on a time axis.
- FIG. 18 is a diagram showing a sound pressure level measured by a microphone on a time axis.
- FIG. 19 is a diagram showing a sound pressure level measured by a microphone on a time axis.
- FIG. 20 is a schematic block diagram of a system for detecting a resonance frequency in a loudspeaker space (for example, a concert hall or a gymnasium).
- a resonance frequency in a loudspeaker space for example, a concert hall or a gymnasium.
- FIG. 21 is a schematic block diagram of a system for detecting a resonance frequency in a sound space (for example, a concert hall or a gymnasium).
- FIG. 22 is a diagram showing a sound pressure level measured by a microphone on a time axis.
- FIG. 23 is a diagram showing a sound pressure level measured by a microphone on a time axis.
- FIG. 24 is a schematic block diagram of a system for detecting a resonance frequency in a public space (for example, a concert hall or a gymnasium).
- a public space for example, a concert hall or a gymnasium.
- FIG. 25 is a diagram showing a sound pressure level measured by a microphone on a time axis.
- FIG. 26 is a diagram showing a sound pressure level measured by a microphone on a time axis.
- FIG. 27 is a characteristic diagram obtained by extracting only the curve Cb from FIG.
- FIG. 1 is a schematic configuration diagram of an acoustic system installed in a sound space (for example, a resonance space where resonance occurs like a concert hall or a gymnasium) 40.
- This acoustic system includes a sound source device 2, a dip filter 4, an amplifier 12, and a speaker 13.
- the sound source device 2 may be, for example, a performance device such as a CD player for reproducing a music CD, or may be a microphone.
- the sound source device 2 is shown outside the sound space 40.
- the force sound source device 2 may be installed in the sound space 40.
- the sound source device 2 may be a microphone installed in the sound space 40.
- the dip filter 4 removes a signal component of a specific frequency output from the sound source device 2 and sends it to the amplifier 12.
- the output signal of the dip filter 4 is amplified by the amplifier 12 and sent out to the speaker 13, and the speaker 13 is amplified in the speaker space 40.
- a resonance frequency is detected in the loudspeaker space 40, and a frequency to be set as the center frequency of the dip in the dip filter 4 is selected from the detected resonance frequencies.
- FIG. 2 is a schematic block diagram of a system Sa for measuring amplitude frequency characteristics in a public space (for example, a concert hall or a gymnasium) 40.
- the system Sa includes a transmitter 11 serving as a sound source means for generating a signal for measurement, an amplifier 12 for inputting a signal generated by the transmitter 11 and amplifying power, and a speaker 13 for inputting an output signal of the amplifier 12 and loudspeaking. And a microphone 14 for receiving a loudspeaker sound emitted by the speed 13 and a measuring device 15 for inputting an output signal of the microphone 14.
- the microphone 14 may be a sound level meter.
- the speaker 13 and the microphone 14 are arranged in the sound space 40.
- the microphone 14 makes the reflected sound in the loudspeaker space 40 sufficiently large compared to the direct sound from the speaker 13. It is placed in a position where you can receive sound at the level.
- the transmitter 11 emits a sine wave signal whose frequency changes with time as a measurement signal. That is, the transmitter 11 transmits a sine wave sweep signal. In the sine wave sweep signal, the level of the sine wave is constant at each point in the frequency sweep.
- Measuring device 15 has a band-pass filter whose center frequency changes with time. This band-pass filter changes the center frequency over time in response to the change over time of the frequency of the sine wave sweep signal transmitted by the transmitter 11. Therefore, measuring device 15 can measure the amplitude characteristic of the frequency at that time by detecting the level of the output signal of microphone 14 via this bandpass filter.
- FIG. 3 is a schematic block diagram of a system Sb for measuring the amplitude frequency characteristic in the loudspeaker space 40.
- This system Sb is obtained by simply adding a path for synthesizing a certain signal to the system Sa in FIG.
- the system Sb in FIG. 3 includes a transmitter 11 serving as a sound source means for emitting a signal for measurement, a mixing device 16, an amplifier 12 which receives an output signal of the mixing device 16 and amplifies the signal, and an amplifier 12
- the loudspeaker 13 includes a speaker 13 that receives an output signal and loudspeaks, a microphone 14 that receives a loudspeaker radiated by the speaker 13, and a measuring device 15 that receives an output signal of the microphone phone 14.
- the speaker 13 and the microphone 14 are arranged at the same position in the sound space 40 as in the system Sa in FIG.
- the transmitter 11, the amplifier 12, the speaker 13, the microphone 14, and the measuring device 15 in the system Sb in FIG. 3 are the same as those in the system Sa in FIG.
- the difference between the system Sb in Fig. 3 and the system Sa in Fig. 2 is that, in the system Sa in Fig. 2, the amplifier 12 receives a signal from the transmitter 11, whereas the system Sb in Fig. 3 In Sb, the amplifier 12 receives a signal from the mixing device 16.
- the mixing device 16 shown in FIG. 3 inputs the measurement signal (sine wave sweep signal) from the transmitter 11 and the output signal of the microphone 14, synthesizes (mixes) these input signals, and generates the synthesized signal (mixing). (Mixing signal).
- FIG. 4 schematically shows amplitude frequency characteristics of the loudspeaker space 40 measured by the system Sa of FIG. 2 and amplitude frequency characteristics of the loudspeaker space 40 measured by the system Sb of FIG. It is a characteristic diagram.
- a curve Ca indicated by a solid line is an amplitude frequency characteristic by the system Sa in FIG. 2
- a curve Cb indicated by a broken line is an amplitude frequency characteristic by the system Sb in FIG.
- Both the system Sa in Fig. 2 and the system Sb in Fig. 3 measure amplitude values at a number of frequency points. For example, in the frequency range to be measured, measure the amplitude value at 1Z192 octave intervals.
- the measured values at the multiple points may be represented on the curves Ca and Cb as the amplitude frequency characteristics of the loudspeaker space 40 without being smoothed on the frequency axis.
- Curves Ca and Cb may be drawn by smoothing on the frequency axis.
- the smoothing method may be performed with various forces, for example, a moving average. For example, a moving average of 9 points on the frequency axis may be applied to the measured values of many frequency points.
- the smoothed curve Cb is also preferably used.
- the curve Ca is obtained by a moving average of 9 points on the frequency axis
- the curve Cb is also preferably obtained by a moving average of 9 points on the frequency axis.
- the amplitude frequency characteristics of the solid curve Ca in FIG. 4 include not only the characteristics of the electroacoustic system using the amplifier 12, the speaker 13, and the microphone 14, but also the characteristics of the resonance of the loudspeaker space 40. .
- the amplitude frequency characteristics of the broken curve Cb in FIG. 4 include not only the characteristics of the electroacoustic system using the amplifier 12, the speaker 13, and the microphone 14, but also the resonance characteristics of the loudspeaker space 40. Due to the feedback loop in which the signal is input to the amplifier 12 and output from the speaker 13, the resonance characteristics of the loudspeaker space 40 appear more emphasized than the amplitude frequency characteristics of the real curve Ca. Further, the amplitude frequency characteristic of the broken curve Cb in FIG.
- the frequency characteristic shown in FIG. 5 is a characteristic obtained by subtracting the characteristic of the characteristic force Ca of the broken curve Cb in FIG.
- the frequency that shows a peak in the positive direction in the characteristic curve Db in FIG. Wave number fl, frequency f21 and frequency f3. It is highly likely that these frequencies that peak in the positive direction are forces that are resonance frequencies or feedback frequencies.
- the number of resonance frequencies in the loudspeaker space 40 is not limited to one, but is often plural. Also, the number of feedback frequencies is not limited to one, but is often plural.
- One or more of the frequencies fl, f21, and f3 may be the resonance frequency, and one or more of the frequencies may be the feedback frequency.
- the feedback frequency referred to here is the feedback frequency in the system Sb in FIG.
- the feedback loop includes an electric path from the microphone 14 to the speaker 13 and an acoustic path from the speaker 13 to the microphone 14.
- the microphone 14 is a measurement microphone for measuring the acoustic characteristics of the sound space 40. Therefore, for example, it is not necessary to set this feedback frequency as a dip frequency in a dip filter in an electroacoustic system that is permanently installed in the loudspeaker space 40. Therefore, it is desirable to know which of the frequencies fl, f21 and f3 in FIG. 5 is the resonance frequency. That is, it is desirable that the resonance frequency can be detected separately from the feedback frequency. For this purpose, it is effective to perform measurement using the system Sc shown in FIG.
- FIG. 6 is a schematic block diagram of a system Scl, Sc 2 for measuring the amplitude frequency characteristic in the loudspeaker space 40.
- FIG. 6 (a) shows the system Scl
- FIG. 6 (b) shows the system Sc2. .
- These systems Scl and Sc2 are obtained by simply adding a delay device 17 to the system Sb in FIG.
- the systems Scl and Sc2 shown in FIG. 6 include a transmitter 11, which is a sound source for generating a signal for measurement, a mixing device 16, an amplifier 12 for amplifying a signal, and an output signal of the amplifier 12.
- a speaker 13 for loudspeaking, a microphone 14 for receiving a loudspeaker radiated by the speaker 13, a measuring device 15 for inputting an output signal of the microphone 14, and a delay device 17 are provided.
- the speaker 13 and the microphone 14 are arranged at the same position in the sound space 40 as in the system Sa in Fig. 2.
- the transmitter 11, the amplifier 12, the speaker 13, the microphone 14, and the measuring device 15 in the systems Scl and Sc2 in FIG. 6 are the same as those in the system Sa in FIG. In these respects, the system Scl, Sc2 in Fig. 6 is Common with Sb.
- the system Scl and Sc2 in Fig. 6 differ from the system Sb in Fig. 3 in the following points. That is, in the system Sb of FIG. 3, the mixing device 16 inputs the measurement signal (sine wave sweep signal) from the transmitter 11 and the output signal of the microphone 14, and combines these input signals ( Mixing) and sends the synthesized signal to the amplifier 12.
- the measurement signal sine wave sweep signal
- the mixing device 16 inputs the measurement signal (sine wave sweep signal) from the transmitter 11 and the output signal of the microphone 14, and combines these input signals ( Mixing) and sends the synthesized signal to the amplifier 12.
- a composite signal of the measurement signal (sine-wave sweep signal) from the transmitter 11 and the output signal of the microphone 14 is transmitted by the delay device 17. After being delayed, it is input to the amplifier 12.
- the mixing device 16 delays the signal for measuring the force of the transmitter 11 (sine wave sweep signal) and the output signal of the microphone 14 by the delay device 17. A delay signal is input, the input signals are combined (mixed), and the combined signal is sent to the amplifier 12.
- the measurement signal and the delay signal obtained by delaying the output signal of the microphone 14 by the delay device 17 are amplified from the speaker 13.
- FIG. 7 schematically shows amplitude frequency characteristics of the loudspeaker space 40 measured by the system Sa of FIG. 2 and amplitude frequency characteristics of the loudspeaker space 40 measured by the system Scl or the system Sc2 of FIG. It is a characteristic diagram. Strictly speaking, the amplitude frequency characteristics measured by the system Scl in Fig. 6 (a) and the amplitude frequency characteristics measured by the system Sc2 in Fig. 6 (b) are not the same! / ⁇ . Is explained without IJ.
- a curve Ca indicated by a solid line is an amplitude frequency characteristic by the system Sa in FIG. 2
- a curve Cc indicated by a broken line is an amplitude frequency characteristic by the systems Scl and Sc2 in FIG.
- the systems Scl and Sc2 in Fig. 6 also measure amplitude values at a number of frequency points, similarly to the system Sa in Fig. 2 and the system Sb in Fig. 3. For example, measure the amplitude value at 1Z192 octave intervals in the frequency range to be measured.
- the measured values at these multiple points may be represented on the curves Ca and Cc as the amplitude frequency characteristics of the loudspeaker space 40 without being smoothed on the frequency axis, or may be represented by some method.
- the above may be smoothed and represented by curves Ca and Cc. There are various forces such as movement
- the smoothing may be performed by the average.
- a moving average of 9 points on the frequency axis may be applied to the measured values of many frequency points.
- the curve Cc it is preferable to use the curve Cc that has been smoothed. In this case, it is preferable to obtain the curve Cc by the same smoothing method as the method for the curve Ca.
- the amplitude frequency characteristics of the real curve Ca include not only the characteristics of the electroacoustic system including the amplifier 12, the speaker 13, and the microphone 14, but also the characteristics of the resonance of the loudspeaker space 40. It is.
- the systems Scl and Sc2 of FIG. 6 include a feedback loop in which a delay signal obtained by delaying the output signal of the microphone 14 is input to the amplifier 12 and output from the speaker 13.
- the amplitude frequency characteristics of the broken curve Cc in FIG. 7 not only show the characteristics of the electroacoustic system due to the amplifier 12, the speaker 13, and the microphone 14, but also show the resonance characteristics of the loudspeaker space 40 of the real curve Ca. Appears emphasized more than the amplitude frequency characteristics.
- the amplitude frequency characteristic of the broken curve Cc in FIG. 7 includes the characteristic due to the feedback due to a feedback loop in which a delay signal obtained by delaying the output signal of the microphone 14 is input to the amplifier 12 and output from the speaker 13. Let's do it.
- the resonance characteristics of the loudspeaker space 40 are greatly emphasized, and the characteristics due to the feedback also appear.
- the broken curve Cc in FIG. Common to the breaking curve Cb of 4.
- the configuration of the feedback loop of the systems Scl and Sc2 of FIG. 6 is not the same as the configuration of the feedback loop of the system Sb of FIG. Therefore, the characteristic due to the feedback appearing in the broken curve Cc in FIG. 7 is different from the characteristic due to the feedback appearing in the broken curve Cb in FIG.
- the frequency characteristic shown in FIG. 8 is a characteristic obtained by subtracting the characteristic of the real curve Ca from the characteristic of the broken curve Cc in FIG.
- the frequencies showing peaks in the positive direction are frequency fl, frequency f22, and frequency f3. These positive peak frequencies are likely to be resonance frequencies or feedback frequencies.
- the frequency characteristics in Fig. 5 show peaks in the positive direction at frequency fl, frequency f21, and frequency f3, and the frequency characteristics in Fig. 8
- the numerical characteristics show peaks in the positive direction at the frequency fl, the frequency f22, and the frequency f3.
- the frequency fl and the frequency f3 are frequencies that commonly show a positive peak in the frequency characteristics of both figures.
- the frequency f21 is a frequency that shows a peak in the positive direction only in the frequency characteristic of FIG.
- the frequency f22 is a frequency that shows a peak in the positive direction only in the frequency characteristic of FIG.
- the characteristics due to the feedback appearing in the broken line Cc in FIG. 7 are different from the characteristics due to the feedback appearing in the broken line Cb in FIG. Therefore, it can be considered that the frequency that shows a peak in the positive direction due to feedback in the frequency characteristic of FIG. 5 is different from the frequency that shows a peak in the positive direction due to feedback in the frequency characteristic of FIG. be able to.
- the frequency fl and the frequency f3 are the resonance frequencies of the loudspeaker space 40
- the frequency f21 is the feedback frequency based on the feedback loop of the system Sb in FIG. 3
- the frequency f22 is the system Scl in FIG. , Can be considered as the feed knock frequency based on the feedback loop of Sc2.
- the frequency fl and the frequency f 3 should be set as the center frequency of the dip for the dip filter 4.
- the system Sb in FIG. 3 is not provided with a delay device. It can also be considered that the output signal of the microphone mouthphone 14 is delayed by 0 second and transmitted to the mixing device 16. Then, the difference between the system Sb in FIG. 3 and the systems Scl and Sc2 in FIG. 6 can be considered to be a difference in delay time with respect to the output signal of the microphone 14. That is, in both the system Sb in FIG. 3 and the systems Scl and Sc2 in FIG. 6, the output signal of the microphone 14 is delayed and sent to the force mixing device 16, but the delay is It can be considered that the time is different between the system Sb in FIG. 3 and the systems Scl and Sc2 in FIG.
- the delay device 17 in the systems Scl and Sc2 in FIG. Any device that can set the delay time arbitrarily can use the systems Scl and Sc2 in FIG. 6 to detect the resonance frequency separately from the feedback frequency without using the system Sb in FIG. That is, the measurements in the systems Scl and Sc2 of FIG. 6 are performed twice. However, in the two measurements, the delay time set in the delay device 17 must not be the same. For example, in the first measurement, the delay time may be set to lm seconds, and in the second measurement, the delay time may be set to 2 ms. Further, for example, the delay time may be set to Om seconds in the first measurement, and the delay time may be set to lm seconds in the second measurement.
- the resonance frequency can be detected separately from the feedback frequency by performing the measurement once in the system Sa in FIG. 2 and twice in the systems Scl and Sc2 in FIG. 6. It is.
- time difference Asing how much difference (time difference) is provided in the delay time between the first measurement and the second measurement, the following method can be adopted. That is, in FIG. 5, a time difference is provided that does not coincide with the period of the frequency indicating the peak in the positive direction (for example, frequency 1).
- the 200 Hz power S feedback frequency is also used in the second measurement. Will be. Then, after all, it becomes impossible to judge whether 200Hz is the power of the resonance frequency or the feedback frequency.
- the frequencies that may be the resonance frequencies (frequency fl, frequency f21, and frequency f3 in Fig. 5) are detected by the first measurement
- these frequencies are detected by the second measurement.
- a time difference that does not at least match the period of these frequencies is provided between the delay time in the first measurement and the delay time in the second measurement. It is better to do so. For example, a time difference of one-fourth of the frequency cycle may be provided.
- FIG. 9 is a schematic block diagram of systems Sdl and Sd2 including the detection devices 201 and 202 as one embodiment of the resonance frequency detection device according to the present invention.
- FIG. 9A shows the detection device 201 and the system. The Sdl force is shown, and
- FIG. 9 (b) shows the detection device 202 and the system Sd2.
- the systems Sdl and Sd2 include detection devices 201 and 202, an amplifier 12 for inputting a signal generated by the detection devices 201 and 202 and amplifying the power, and a speaker 13 for inputting an output signal of the amplifier 12 and loudspeaking; And a microphone 14 for receiving a loud sound emitted by the speaker 13.
- the detection devices 201 and 202 receive the output signal of the microphone 14.
- the speaker 13 and the microphone 14 are arranged in a sound space (for example, a concert hall or a gymnasium) 40.
- Microphone 14 is arranged at a position where it can receive the reflected sound in sound space 40 at a sufficiently large level with respect to the direct sound from speaker 13.
- the detection devices 201 and 202 include a transmission unit 21, a measurement control unit 25, a mixing unit 26, an opening / closing unit 27, and a delay device 28 with a variable delay time.
- the transmitting section 21 functions as a sound source means for transmitting a measurement signal.
- the measurement 'control unit 25 functions as a control unit that controls each unit in the detection devices 201 and 202, and also functions as a measurement unit that measures a frequency characteristic.
- the delay device 28 functions as a delay unit. Further, the mixing unit 26, the opening / closing unit 27, and the delay device 28 constitute a signal switching unit.
- the measurement and control unit 25 controls the transmission unit 21 to output a measurement signal from the transmission unit 21.
- the measurement signal is a sine wave signal whose frequency changes with time, that is, a sine wave sweep signal.
- the level of the sine wave is constant at each point in the frequency sweep.
- the mixing unit 26 combines (mixes) the signal from the transmitting unit 21 and the signal from the opening and closing unit 27, and generates a combined signal (mixing signal). ) Is output.
- the synthesized signal is delayed by the delay device 28, input to the amplifier 12, amplified in power, input to the speaker 13, and radiated from the speaker 13 to the sound space 40 as sound.
- the sound in the loudspeaker space 40 is received by the microphone 14, and the output signal of the microphone 14 is input to the detection device 201.
- the output signal of the microphone 14 is branched and transmitted to the measurement / control unit 25 and the opening / closing unit 27.
- the mixing unit 26 combines (mixes) the signal from the transmission unit 21 and the signal from the opening / closing unit 27, and outputs the combined signal (mixing). Signal) Output.
- the output signal of the mixing section 26 is power-amplified by the amplifier 12, input to the speaker 13, and radiated from the speaker 13 to the loudspeaker space 40 as loudspeaker sound.
- the sound in the loudspeaker space 40 is received by the microphone 14, and the output signal of the microphone 14 is input to the detection device 202.
- the output signal of the microphone 14 is branched and sent to the measurement / control unit 25 and the delay device 28.
- the output signal of the delay device 28 is sent to the opening / closing section 27.
- the measurement 'control unit 25 has a band-pass filter whose center frequency changes with time. This band-pass filter temporally changes the center frequency in response to a temporal change in the frequency of the sine wave sweep signal transmitted by the transmitting unit 21. Therefore, the measurement 'control unit 25 can measure the amplitude characteristic of the frequency at that time by detecting the level of the output signal of the microphone 14 through this bandpass filter.
- the measurement 'control unit 25 can control the opening and closing of the opening and closing unit 27. Therefore, the opening / closing section 27 can be set to the “open” state and only the measurement signal from the transmitting section 21 can be loudspeaked from the speaker 13, or the opening / closing section 27 can be set to the “closed” state and the measurement from the transmitting section 21 can be performed.
- the signal for use and the delay signal of the output signal of the microphone 14 can be amplified from the speaker 13.
- the measurement and control unit 25 can set at least two types of delay times in the delay device 28.
- the delay time of the delay device 28 may be arbitrarily set to one of Om seconds and lm seconds, or may be set to one of lm seconds and 2 m seconds. May be set. Also, it can be set to any of Om seconds, lm seconds and 2ms.
- the opening / closing section 27 is set to the “closed” state and the delay time of the delay device 28 is set to Om seconds, the same amplitude frequency characteristics as those measured by the system Sb in FIG. 3 can be measured.
- the opening / closing unit 27 is set to the “closed” state and the delay time of the delay device 28 is set to a predetermined time other than 0 (for example, lm seconds), the delay time of the delay device 17 of the systems Scl and Sc2 in FIG. (Example For example, it is possible to measure the same amplitude frequency characteristics as when measuring with setting the delay time to lm seconds).
- the resonance frequency of the loudspeaker space 40 can be detected from the amplitude frequency characteristics measured in this manner, separately from the feedback frequency. All the operations for detecting the measured amplitude frequency characteristic force and the resonance frequency are performed by the measurement 'control unit 25.
- the procedure of detecting the resonance frequency by setting the delay time of the delay device 28 to Om seconds and a predetermined time other than 0 (eg, lm seconds) in the systems Sdl and Sd2 has been described.
- the delay time of the delay device 28 is set to a first non-zero delay time (for example, lm seconds) and a second non-zero delay time (for example, 2 ms).
- the resonance frequency can be detected.
- the delay time can be switched between two ways. Then, one of these two delay times may be Om seconds, or both may be non-zero times! /.
- FIG. 10 is a diagram showing an example of a configuration that can be adopted as the delay device 28 in the detection devices 201 and 202 in FIG.
- a delay device 28a as shown in FIG. 10 (a) may be employed, or a delay device 28b as shown in FIG. 10 (b) may be employed.
- the delay device 28a of FIG. 10A includes a switching switch 29 and a delay element 50 having a delay time fixed to a predetermined time other than 0 (for example, lm seconds). By controlling the switching of the switching switch 29, the delay time of the delay device 28a can be switched between Om seconds and the predetermined time (for example, lm seconds).
- the delay device 28b shown in FIG. 10 (b) includes a delay element 51 that can set a delay time arbitrarily within a predetermined time range.
- the delay time of the delay element 51 may be switched between, for example, Om seconds and lm seconds, or may be switched between, for example, lm seconds and 2 m seconds.
- FIG. 11 is a schematic block diagram of systems Sel and Se2 for measuring the amplitude frequency characteristic in the loudspeaker space 40.
- FIG. 11 (a) shows the system Sel, and FIG. ) Shows the system Se2! /
- the systems Sel and Se2 are obtained by simply adding a phase inverter 19 to the system Sb in FIG.
- the systems Sel and Se2 shown in FIG. 11 include a transmitter 11 as a sound source that emits a measurement signal, a mixing device 16, an amplifier 12 that amplifies the signal, and an output signal of the amplifier 12 to be input and amplified. It includes a speaker 13, a microphone 14 for receiving a loud sound emitted by the speaker 13, a measuring device 15 for inputting an output signal of the microphone 14, and a phase inverting device 19 for inverting the phase of the input signal and outputting the inverted signal. .
- the speaker 13 and the microphone 14 are arranged in the loudspeaker space 40 at the same position as in the system Sa in Fig. 2.
- the transmitter 11, the amplifier 12, the speaker 13, the microphone 14, and the measuring device 15 in the systems Sel and Se2 in FIG. 11 are the same as those in the system Sa in FIG. In these respects, the systems Sel and Se2 in FIG. 11 are common to the system Sb in FIG.
- the system Sel and Se2 in Fig. 11 differ from the system Sb in Fig. 3 in the following points. That is, in the system Sb in FIG. 3, the mixing device 16 inputs the measurement signal (sine wave sweep signal) from the transmitter 11 and the output signal of the microphone 14, and combines these input signals. (Mixing) and sends the power to the amplifier 12.
- the measurement signal sine wave sweep signal
- the mixing device 16 inputs the measurement signal (sine wave sweep signal) from the transmitter 11 and the output signal of the microphone 14, and combines these input signals. (Mixing) and sends the power to the amplifier 12.
- the mixing device 16 converts the combined signal of the measurement signal (sine wave sweep signal) from the transmitter 11 and the output signal of the microphone 14 into The signal is input to the phase inverting device 19 to invert the phase, and then transmitted to the amplifier 12.
- the mixing device 16 includes the measurement signal (sine wave sweep signal) from the transmitter 11 and the output of the phase inversion device 19 to which the output signal of the microphone 14 is input. A signal is input, the input signals are combined (mixed), and the combined signal is sent to the amplifier 12.
- the speaker 13 loudspeakers a measurement signal and a phase-inverted signal obtained by inverting the phase of the output signal of the microphone 14.
- Fig. 12 schematically shows the amplitude frequency characteristics of the loudspeaker space 40 measured by the system Sa of Fig. 2 and the amplitude frequency characteristics of the loudspeaker space 40 measured by the systems Sel and Se2 of Fig. 11. It is a characteristic diagram. Strictly speaking, the amplitude-frequency characteristics measured by the system Sel in Fig. 11 (a) and the amplitude-frequency characteristics measured by the system Se2 in Fig. 11 (b) are not the same. It will be explained without any explanation.
- a curve Ca 1S shown by a solid line is an amplitude frequency characteristic by the system Sa of FIG. 2
- a curve Ce shown by a broken line is an amplitude frequency characteristic by the systems Sel and Se2 of FIG.
- the systems Sel and Se2 in Fig. 11 also measure amplitude values at a number of frequency points, similarly to the system Sa in Fig. 2 and the system Sb in Fig. 3. For example, in the frequency range to be measured, measure the amplitude value at 1Z192 octave intervals.
- the measured values at these multiple points may be represented on the curves Ca and Ce as the amplitude frequency characteristics of the loudspeaker space 40 without being smoothed on the frequency axis, or the frequency may be represented by some method.
- the curves Ca and Ce may be drawn by smoothing on the axis. The method of smoothing at this time may be smoothing by various forces such as a moving average.
- a moving average of 9 points on the frequency axis may be applied to the measured values of many frequency points.
- the thing which was smoothed as the curve Ca it is preferable to also use the thing which was smoothed about the curve Ce.
- the curve Ce is obtained by the same smoothing method as that for the curve Ca.
- the amplitude frequency characteristics of the real curve Ca include not only the characteristics of the electroacoustic system including the amplifier 12, the speaker 13, and the microphone 14, but also the characteristics of the resonance of the loudspeaker space 40. It is.
- the systems Sel and Se2 in FIG. 11 include a feedback loop in which a phase inverted signal of the output signal of the microphone 14 is input to the amplifier 12 and output from the speaker 13. Therefore, the amplitude frequency characteristics of the broken curve Ce in FIG. 12 not only show the characteristics of the electroacoustic system using the amplifier 12, the speaker 13, and the microphone 14, but also show the resonance characteristics of the loudspeaker space 40 as the real curve Ca. Appears emphasized more than the amplitude frequency characteristics! Furthermore, the broken curve in Fig. 12 The amplitude frequency characteristic of Ce includes the characteristic due to this feedback due to a feedback loop in which a phase inversion signal of the output signal of the microphone 14 is input to the amplifier 12 and output from the speaker 13.
- the broken curve Ce in FIG. 12 is different from the broken curve Cb in FIG. Common.
- the configuration of the feedback loop of the system Sel, Se2 of FIG. 11 is not the same as the configuration of the feedback loop of the system Sb of FIG. Therefore, the characteristic due to the feedback shown in the broken curve Ce in FIG. 12 is different from the characteristic due to the feedback shown in the broken curve Cb in FIG.
- the frequency characteristic shown in FIG. 13 is a characteristic obtained by subtracting the characteristic of the real curve Ca from the characteristic of the broken curve Ce in FIG.
- the frequencies showing peaks in the positive direction are frequency fl, frequency f23, and frequency f3. These positive peak frequencies are likely to be resonance frequencies or feedback frequencies.
- the frequency characteristic of FIG. 5 shows a positive peak at the frequency fl, the frequency f21 and the frequency f3, and the frequency characteristic of FIG. 13 shows a positive peak at the frequency fl, the frequency f23 and the frequency f3.
- the frequency fl and the frequency f3 are frequencies that have a common positive peak in the frequency characteristics of both figures.
- the frequency f21 is a frequency that shows a peak in the positive direction only in the frequency characteristic of FIG.
- the frequency f23 is a frequency that shows a peak in the positive direction only in the frequency characteristic of FIG.
- the configuration of the feedback loop of system Sel and Se2 in FIG. 11 is different from the configuration of the feedback loop of system Sb in FIG. Therefore, the characteristics due to the feedback appearing in the break curve Ce in FIG. 12 are different from the characteristics due to the feedback appearing in the break curve Cb in FIG. Therefore, it can be considered that the frequency that shows a peak in the positive direction due to feedback in the frequency characteristic of FIG. 5 is different from the frequency that shows a peak in the positive direction due to feedback in the frequency characteristic of FIG. Can be.
- the frequency fl and the frequency f3 are the resonance frequencies of the loudspeaker space 40
- the frequency f21 is the feedback frequency based on the feedback loop of the system Sb in FIG. 3
- the frequency f23 is the system Sel in FIG. Therefore, it can be considered that the feedback frequency is based on the feedback loop of Se2.
- the frequency fl and the frequency f 3 should be set as the center frequency of the dip for the dip filter 4.
- FIG. 14 is a detection apparatus as one embodiment of the resonance frequency detection apparatus according to the present invention.
- FIG. 14A is a schematic block diagram of the systems Sfl and Sf2 including 301 and 302.FIG. 14A shows the detection device 301 and the system Sfl, and FIG. 14B shows the detection device 302 and the system Sf2. I have.
- the systems Sfl and Sf2 include detection devices 301 and 302, an amplifier 12 that inputs signals generated by the detection devices 301 and 302 and amplifies the power, and a speed 13 that inputs an output signal of the amplifier 12 and loudspeaks. And a microphone 14 for receiving a loud sound emitted by the speaker 13.
- the detection devices 301 and 302 receive the output signal of the microphone 14.
- the speaker 13 and the microphone 14 are arranged in a sound space (for example, a concert hall or a gymnasium) 40. Microphone 14 is arranged at a position where it can receive the reflected sound in sound space 40 at a sufficiently large level with respect to the direct sound from speaker 13.
- the detection devices 301 and 302 include a transmission unit 21, a measurement control unit 25, a mixing unit 26, an opening and closing unit 27, a switching switch 31, and a phase inversion device 32.
- the transmitting unit 21 functions as a sound source unit that emits a measurement signal.
- the measurement control unit 25 functions as control means for controlling each unit in the detection devices 301 and 302, and also functions as measurement means for measuring frequency characteristics.
- the phase inversion device 32 functions as a phase inversion means.
- the mixing section 26, the opening / closing section 27, the switching switch 31, and the phase inverting device 32 constitute signal switching means.
- the measurement and control unit 25 controls the transmission unit 21 to output a measurement signal from the transmission unit 21.
- This measurement signal is a sine wave signal whose frequency changes with time, that is, a sine wave sweep signal.
- the sine wave level is constant at each point in the frequency sweep. It is.
- Mixing section 26 combines (mixes) the signal from transmitting section 21 and the signal from opening / closing section 27, and outputs the combined signal (mixing signal).
- the signal input to the amplifier 12 is power-amplified and input to the speaker 13, and is radiated from the speaker 13 to the loudspeaker space 40 as loudspeaker sound.
- the sound in the loudspeaker space 40 is received by the microphone 14, and the output signal of the microphone 14 is input to the detection devices 301 and 302.
- the output signal of the microphone 14 is branched and sent to the measurement / control unit 25 and the switch 27.
- the output signal power of the mixing section 26 is divided into a phase inverting device 32 and a switching switch 31 for transmission.
- the output signal of the phase inverter 32 is also sent to the switching switch 31. Then, a signal from the switching switch 31 is input to the amplifier 12.
- the output signal of the microphone 14 is branched to the measurement control unit 25, the phase inversion device 32, and the switching switch 31 and transmitted.
- the output signal of the phase inverter 32 is sent to the switching switch 31.
- the switching switch 31 is connected to the opening / closing section 27. Then, the output signal of the mixing section 26 is input to the amplifier 12.
- the measurement 'control unit 25 of the detection devices 301 and 302 has a band-pass filter whose center frequency changes with time. This band-pass filter changes the center frequency over time in response to the time-dependent change of the frequency of the sine wave sweep signal transmitted by the transmitting unit 21. Therefore, the measurement 'control section 25 can measure the amplitude characteristic of the frequency at that time by detecting the level of the output signal of the microphone 14 via this bandpass filter.
- the measurement 'control unit 25 can control the opening and closing of the opening and closing unit 27. Therefore, the opening / closing section 27 can be set to the “open” state, and only the measurement signal from the transmitting section 21 can be amplified from the speaker 13. The use signal and the output signal of the microphone can be amplified from the speaker 13.
- the measurement / control section 25 can control the state of the switching switch 31. Therefore, the phase of the output signal of the microphone 14 is inverted by passing the output signal of the microphone 14 through the phase inverting device 32. Later, the speaker 13 can select whether or not to make the speaker louder.
- the feedback frequency is distinguished from the feedback frequency.
- the resonance frequency of the loudspeaker space 40 can be detected. All the operations for detecting the measured amplitude frequency characteristic force and the resonance frequency are performed by the measurement 'control unit 25.
- the apparatus and method for detecting the resonance frequency by distinguishing it from the feedback frequency by inverting the phase of the output signal of as many as 14 microphones arranged in the sound space 40 have been described.
- the transmitter or the transmitter transmits a sine-wave sweep signal as a measurement signal.
- the signal for measurement is not limited to the sine wave sweep signal, and various signals can be used.
- a noise signal having a component within a predetermined frequency width, whose center frequency is swept.
- the frequency width is preferably set to 1Z3 octave or less.
- the pitch be 1 octave or less.
- pink noise can be used as the measurement signal.
- the measuring instrument does not need to have a bandpass filter whose center frequency changes with time.
- FIG. 15 shows the resonance frequency in a loudspeaker space (for example, a concert hall or a gymnasium) 40.
- FIG. 2 is a schematic block diagram of a detection system and a detection device (resonance frequency detection device).
- the system Sg in FIG. 15 includes a transmitter 111 that is a sound source for generating a measurement signal, an amplifier 12 that inputs a signal generated by the transmitter 111 and amplifies power, and an output signal of the amplifier 12 is input.
- a speaker 13 for receiving a loud sound emitted by the speaker 13; and a measurement and control unit 115 for inputting an output signal of the microphone 14.
- Microphone 14 may be a sound level meter.
- the measurement and control unit 115 controls the transmitter 111. That is, the frequency of the measurement signal output from the transmitter 111 and the time interval of the measurement signal can be controlled.
- the measurement / control section 115 also functions as a measuring means for measuring the attenuation characteristic of the output signal of the microphone 14.
- the transmitter 111 and the measurement and control unit 115 constitute a detection device 400.
- the speaker 13 and the microphone 14 are arranged in the loudspeaker space 40.
- the microphone 14 is arranged at a position where it can receive the reflected sound in the sound space 40 at a sufficiently large level with respect to the direct sound from the speaker 13.
- the measurement signal output from the transmitter 111 of the system Sg is a signal in which the reference frequency signal is intermittently repeated a plurality of times.
- the reference frequency signal is a sine wave signal of a specific frequency or a signal having a component within a predetermined frequency width around the specific frequency.
- the signal having a component within a predetermined frequency range around a specific frequency is, for example, a noise signal having a frequency component of 1/3 octave width around 200 Hz. The use of such a reference frequency signal makes it less susceptible to noise such as background noise, and enables highly reliable measurement.
- FIG. 16 is a diagram showing the signal levels of the above-described measurement signals on a time axis.
- a sine wave power of 200Hz which is a specific frequency
- is output continuously for 0.1 second then is output again for 0.1 second with a time interval of 0.9 second, and then a time interval of 0.9 second And output again for 0.1 second.
- a 200Hz sine wave that is intermittently output three times at one second intervals for 0.1 second is output.
- a 200 Hz sine wave lasting 0.1 second is output a plurality of times at equal time intervals, but is not necessarily output at equal time intervals. Do No need.
- a sine wave of a specific frequency that lasts for a predetermined time may be output a plurality of times at random time intervals.
- FIG. 17 is a diagram showing a sound pressure level measured by the microphone 14 on a time axis. Three peak points are generated at one-second intervals in synchronization with the measurement signal shown in FIG. However, the sound pressure level decay is fast. In this way, when the sound pressure level is rapidly attenuated in the loudspeaker space, the specific frequency (200 Hz) of the measurement signal is not considered to be the resonance frequency.
- FIG. 18 is a diagram showing a sound pressure level measured by the microphone 14 on the time axis when a measurement signal having a specific frequency of 250 Hz is output from the speed 13 of the system Sg in FIG. It is.
- a reference frequency signal having a specific frequency of 250 Hz is output from the transmitter 111 for 0.1 second, and then output again for 0.1 second at a time interval of 0.9 second, and further output for 0 second. It is output again for 0.1 second with a time interval of 9 seconds.
- a 250 Hz sine wave that lasts 0.1 second is output three times intermittently at 1 second intervals.
- the attenuation of sound pressure level is moderate.
- the specific frequency (250 Hz) of the measurement signal may be the resonance frequency of the loudspeaker space 40.
- the reference frequency signal does not necessarily need to be emitted from the speaker 13 a plurality of times. For example, a reference frequency signal that lasts for several seconds is emitted only once from 13 speakers, and the resonance frequency can be determined from the attenuation characteristic of the sound pressure level in the loudspeaker space 40. For example, the determination can be made based on whether or not the speed is attenuated more slowly than a predetermined speed.
- the sound pressure level is represented on the time axis.
- the determination may be made by calculating the area of the area surrounded by the sound pressure level curve. In other words, it is determined that the sound pressure level decreases rapidly if the area is small, and that the sound pressure level decreases gradually if the area is large.
- FIG. 19 is a diagram showing a sound pressure level measured by the microphone 14 on the time axis when a measurement signal having a specific frequency of 300 Hz is output from the speed 13 of the system Sg in FIG. It is.
- a reference frequency signal having a specific frequency of 300 Hz is output from the transmitter 111 for 0.1 second, and thereafter is output again for 0.1 second at a time interval of 0.9 second, and then output again for 0.1 second. It is output again for 0.1 second with a time interval of 9 seconds.
- a 300 Hz sine wave that lasts 0.1 second is output three times at intervals of 1 second.
- the attenuation of sound pressure level is moderate.
- the force of the second peak force is slower than that of the first peak, and the damping force of the third peak is slower than that of the second peak.
- the reason why the attenuation gradually decreases is that the energy of the previously output loudspeaker sound sufficiently remains in the loudspeaker space 40 until the next loudspeaker is output. .
- the specific frequency (300 Hz) of the measurement signal is the resonance frequency of the loudspeaker space 40.
- the resonance frequency of the loudspeaker space 40 is detected by determining the state of the attenuation process of the sound pressure level in the loudspeaker space 40 while gradually changing the specific frequency of the measurement signal by the measurement and control unit 115. can do.
- a form in which the specific frequency is increased stepwise by 1/48 octave can be adopted.
- FIG. 20 is a schematic block diagram of a system and a detection device (resonance frequency detection device) for detecting a resonance frequency in a sound space (for example, a concert hall or a gymnasium) 40.
- a detection device for detecting a resonance frequency in a sound space (for example, a concert hall or a gymnasium) 40.
- the system Sh in Fig. 20 also includes a transmitter 111 serving as a sound source for generating a measurement signal, an amplifier 12, and a speaker 13 which receives an output signal of the amplifier 12 and loudspeaks. And a microphone 14 for receiving a loud sound radiated by the speaker 13, and a measurement and control unit 115 for inputting an output signal of the microphone 14.
- the measurement and control unit 115 can control the frequency of the measurement signal output from the transmitter 111 and the time interval of the measurement signal.
- the measurement and control unit 115 is a measuring means for measuring the attenuation characteristic of the output signal of the microphone 14. Also works.
- the detection device 500 includes a transmitter 111, a measurement control unit 115, and a mixing device 116.
- the difference between the system Sh of FIG. 20 and the system Sg of FIG. 15 is that, in the system Sh of FIG. 20, the measurement signal from the transmitter 111 and the output signal of the microphone 14 are mixed (mixed) by the mixing device 116. ) And the combined signal is sent to the amplifier 12.
- the mixing device 116 functions as a signal output unit. As described above, when such a feedback loop is provided, the resonance of the loudspeaker space 40 is measured while being emphasized.
- the system Sh in Fig. 20 can also detect the resonance frequency of the loudspeaker space 40, similarly to the system Sg in Fig. 15. Also, the resonance frequency can be detected more clearly than when the system Sg in FIG. 15 is used.
- FIG. 21 is a schematic block diagram of a system and a detection device (resonance frequency detection device) for detecting a resonance frequency in a public space (for example, a concert hall or a gymnasium) 40.
- FIG. Sil shows the detection device 601
- FIG. 21B shows the system Si2 and the detection device 602.
- the systems Sil and Si2 in Fig. 21 also include a transmitter 111, which is a sound source means for generating a measurement signal, an amplifier 12, and an output signal from the amplifier 12, which are input and amplified.
- the measurement / control section 115 can control the frequency of the measurement signal output from the transmitter 111 and the time interval of the measurement signal.
- the measurement / control section 115 also functions as a measuring means for measuring the attenuation characteristic of the output signal of the microphone 14.
- the detection device 601 includes a transmitter 111, a measurement control unit 115, a mixing unit 116, and a delay device 128.
- the measurement signal from the transmitter 111 and the output signal of the microphone 14 input to the detection device 601 are combined in the mixing section 116, and the combined signal is output from the detection device 601 via the delay device 128.
- the output signal of the detection device 601 is sent to the amplifier 12. Further, the output signal of microphone mouth phone 14 input to detection apparatus 601 is branched and transmitted to measurement / control section 115 and mixing section 116. It is.
- the detection device 602 includes a transmitter 111, a measurement control unit 115, a mixing unit 116, and a delay device 128.
- the measurement signal from the transmitter 111 and the output signal of the delay device 128 are combined in the mixing unit 116, and the combined signal is output from the detection device 601.
- the output signal of the microphone 14 input to the detection device 601 is branched and transmitted to the delay device 128 and the measurement / control unit 115.
- the delay device 128 is controlled by the measurement and control unit 115. That is, the measurement / control section 115 can arbitrarily set the delay time of the delay device 128 within a predetermined time range. For example, in the delay device 128, the delay time of the delay device 128 can be set to Om seconds, lm seconds, or 2 ms.
- a sine wave of a specific frequency of 250 Hz is output from the oscillator 111 for 0.1 second, and after that, at a time interval of 0.9 second again, The output may be continued for 0.1 second, and may be output again for 0.1 second after a time interval of 0.9 second. In other words, it outputs a 250Hz sine wave that lasts for 0.1 second three times intermittently at 1 second intervals.
- FIG. 22 is a diagram showing a sound pressure level measured by the microphone 14 on the time axis when the measurement signal as described above is output from the oscillator 111 of the detection devices 601 and 602. However, at this time, the delay time of the delay device 128 is set to Om seconds.
- the sound pressure level curve has three peak points at one-second intervals in synchronization with the measurement signal.
- the attenuation of the sound pressure level is moderate.
- the specific frequency (250 Hz) of the measurement signal may be the resonance frequency of the loudspeaker space 40. Only However, there is a possibility that this specific frequency (250 Hz) may be a feedback frequency that is not the resonance frequency. Specific frequency (250 Hz) force Even at the feedback frequency, the sound pressure level attenuates slowly.
- the same measurement is performed while changing the delay time of the delay device 128.
- the oscillator 111 outputs a 250 Hz sine wave that lasts for 0.1 second three times intermittently.
- the delay device 128 is used. For example, when measuring the sound pressure level of the loudspeaker space 40 in synchronization with the second output, set the delay time of the delay device 128 to, for example, lm seconds, and set the delay time of the third device to the third output.
- the delay time of the delay device 128 is set to, for example, 2 ms.
- the resonance frequency is determined only by the characteristics of the loudspeaker space 40, it does not change even if the configuration of the feedback loop changes. If the specific frequency (250 Hz) is the resonance frequency, even if the delay time of the delay device 128 is changed, the rate of attenuation of the sound pressure level measured in the loudspeaker space 40 does not change.
- the force feedback frequency changes when the configuration of the feedback loop changes.
- Changing the delay time of the delay device 128 changes the configuration of the feedback loop. Therefore, if the specific frequency (250 Hz) is the feedback frequency when the delay time of the delay device 128 is set to Om seconds, when the delay time of the delay device 128 is changed, it is measured in the sound space 40. The rate of sound pressure level decay also changes.
- FIG. 23 shows the sound pressure level measured by the microphone 14 when the above-described measurement signal is output from the oscillator 111 while changing the delay time of the delay device 128 as described above. It is the figure represented on the time axis. Strictly speaking, the sound pressure level curve measured with the system Sil in Fig. 21 (a) and the sound pressure level curve measured with the system Si2 in Fig. 21 (b) are not the same! In the following, these will be explained without IJ.
- the sound pressure level curve has three peak points at one-second intervals in synchronization with the measurement signal.
- the sound pressure level in the sound space 40 corresponding to the first output from the oscillator 111 is gradually attenuated.
- Loudspeaker sky corresponding to the second output During 40 the sound pressure level decayed relatively quickly.
- the sound pressure level in the loudspeaker space 40 corresponding to the third output is slightly attenuated.
- the specific frequency (250 Hz) of the measurement signal is not the resonance frequency.
- the measurement and control unit 115 determines the state of the sound pressure level attenuation process in the loudspeaker space 40 as described above while gradually changing the specific frequency of the measurement signal.
- the resonance frequency can be detected separately from the feedback frequency.
- FIG. 24 is a schematic block diagram of a system and a detection device (resonance frequency detection device) for detecting a resonance frequency in a public space (for example, a concert hall or a gymnasium) 40.
- a detection device for detecting a resonance frequency in a public space (for example, a concert hall or a gymnasium) 40.
- FIG. The system Sjl and the detection device 701 are shown, and the system Sj2 and the detection device 702 are shown in FIG.
- the systems Sjl and Sj2 in Fig. 24 also include a transmitter 111, which is a sound source means for generating a measurement signal, an amplifier 12, and an output signal of the amplifier 12, which are input.
- the loudspeaker 13 includes a speaker 13 for loudspeaking, a microphone 14 for receiving a loudspeaker radiated by the speaker 13, and a measurement and control unit 115 for inputting an output signal of the microphone 14.
- the measurement / control section 115 can control the frequency of the measurement signal output from the transmitter 111 and the time interval of the measurement signal.
- the measurement / control section 115 also functions as a measuring means for measuring the attenuation characteristic of the output signal of the microphone 14.
- the detection device 701 in FIG. 24A includes a transmitter 111 as a sound source, a measurement / control unit 115, a mixing unit 116, a switching switch 131, and a phase inversion device 132.
- the output signal of the microphone 14 is branched and sent to the measurement / control unit 115 and the mixing unit 116.
- the mixing unit 116 also receives a measurement signal from the transmitter 111.
- the mixing unit 116 combines the output signal of the microphone 14 and the measurement signal from the transmitter 111, and branches and sends the combined signal to the phase inverting device 132 and the switching switch 131.
- the output signal of the phase inverter 132 is also sent to the switching switch 131. Then, the signal from the switching switch 131 is sent to the amplifier 12.
- the detection device 702 in Fig. 24 (b) includes a transmitter 111 as a sound source means, a measurement control unit 115, A kissing unit 116, a switching switch 131, and a phase inversion device 132 are provided.
- the output signal of the microphone 14 is branched and transmitted to the measurement / control unit 115, the phase inversion device 132, and the switching switch 131.
- the output signal of the phase inverter 132 is sent to the switching switch 131.
- the output signal of the switching switch 31 is sent to the mixing section 116.
- the mixing unit 116 also receives a measurement signal from the transmitter 111.
- the mixing unit 116 combines the measurement signal from the transmitter 111 and the signal from the switching switch 131, and sends the combined signal to the amplifier 12.
- the measurement signal is amplified from the speaker 13. Also, the output signal of the microphone 14 or a phase-inverted signal obtained by inverting the phase of the output signal of the microphone 14 is amplified from the speed 13.
- the signal output means is composed of the mixing unit 116, the switching switch 131, and the phase inversion device 132.
- a force for loudspeaking the output signal of the microphone 14 from the speaker 13 without inverting the phase can be selected by switching the switching switch 131 to invert the phase and also loudspeaker.
- the switching switch 131 is controlled by the measurement / control unit 115. Therefore, the measurement / control unit 115 can select whether the output signal of the microphone 14 from the speaker 13 should be amplified without inverting the phase, or whether the output signal should be amplified by inverting the phase.
- the systems Sjl and Sj2 also include a feedback loop. Force As described above, when such a feedback loop is provided, the resonance of the loudspeaker space 40 is more emphasized and measured.
- the switching switch 131 When the switching switch 131 is set so that the output signal of the microphone 14 is amplified from the speaker 13 without inverting the phase, the output signal of the microphone 14 is inverted and the 13-speaking power is also amplified.
- the configuration of the feedback loop is different from when the switching switch 131 is set as described above.
- the oscillator 111 outputs, for example, a sine wave of a specific frequency of 250 Hz for 0.1 second, and after that, at a time interval of 0.9 second again, The output may be continued for 0.1 second, and may be output again for 0.1 second after a time interval of 0.9 second. That is, 3 times intermittently at 1 second intervals, 0.1 second It outputs a 250Hz sine wave that lasts for a while.
- FIG. 25 is a diagram showing a sound pressure level measured by the microphone 14 on the time axis when the above-described measurement signal is output from the oscillator 111 in the systems # 1 and # 2. is there. However, at this time, the state of the switch 131 is set so that the output signal of the microphone 14 can also be amplified by the 13 speakers without inverting the phase.
- the sound pressure level curve has three peak points at one-second intervals in synchronization with the measurement signal.
- the attenuation of the sound pressure level is moderate.
- the specific frequency (250Hz) of the measurement signal may be the resonance frequency of the loudspeaker space 40.
- the feedback frequency may not be at the specific frequency (250 Hz) force resonance frequency.
- Specific frequency (250Hz) force Even if the feedback frequency is used, the sound pressure level decreases gradually.
- the same measurement is performed while switching the switch 131.
- the oscillator 111 intermittently outputs a 250 Hz sine wave lasting 0.1 second three times.
- the The switch 131 is set so that the output signal can be amplified by the speaker 13 without reversing the phase.
- the microphone 14 When measuring the sound pressure level of the amplification space 40 in synchronization with the second output, the microphone 14 The output signal is inverted by the phase inverting device 132, and then the switching switch 131 is set to a state where the sound can be amplified by the speaker 13, and the sound pressure level of the sound space 40 is measured in synchronization with the third output. At times, the switching switch 131 is set so that the output signal of the microphone 14 can be amplified by the speaker 13 without inverting the phase.
- the resonance frequency is determined only by the characteristics of the loudspeaker space 40, and does not change even if the configuration of the feedback loop changes. If the specific frequency (250 Hz) is the resonance frequency, the speed of attenuation of the sound pressure level in the loudspeaker space 40 does not change even if the configuration of the feedback loop changes.
- the feedback frequency varies depending on the configuration of the feedback loop. It changes with the transformation.
- a feedback loop that does not reverse the phase of the output signal of the microphone 14 and a feedback loop that reverses the phase of the output signal of the microphone 14 have different configurations. Therefore, if the feedback frequency is caused by a feedback loop that does not invert the phase of the output signal of the microphone 14 at a specific frequency (250 Hz), the configuration of the feedback loop should be such that the phase of the output signal of the microphone 14 is inverted.
- the speed of sound pressure level decay in the loudspeaker space 40 also changes.
- FIG. 26 is a graph showing the sound pressure level measured by the microphone 14 when the measurement signal as described above is output from the oscillator 111 in the systems Sjl and Sj2 while switching the switch 131. It is the figure represented above. Strictly speaking, the sound pressure level curve measured by the system Sjl in Fig. 24 (a) and the sound pressure level curve measured by the system Sj2 in Fig. 24 (b) are not the same! Here, these will be described without performing IJ.
- the sound pressure level curve has three peak points at one-second intervals in synchronization with the measurement signal.
- the sound pressure level gradually decreases.
- the sound pressure level of the loudspeaker space 40 was measured in synchronization with the second output, the sound pressure level rapidly decreased.
- the sound pressure level of the sound space 40 is measured in synchronization with the third output, the sound pressure level gradually decreases!
- the attenuation speed of the sound pressure level in the loudspeaker space 40 is determined. Since the measurement frequency has changed, it can be determined that the specific frequency (250 Hz) of the measurement signal is not the resonance frequency.
- the measurement and control unit 115 determines the state of the attenuation process of the sound pressure level of the loudspeaker space 40 as described above while gradually changing the specific frequency of the signal for measurement, so that the The resonance frequency can be detected separately from the feedback frequency.
- a predetermined number of internal forces of the frequency fl, the frequency f21, and the frequency f3 are also selected as candidates for the center frequency of the dip to be set as the removal frequency in the dip filter 4.
- candidate frequencies are selected in order from the one with the largest amplitude level of the curve Cb in FIG.
- FIG. 27 is a characteristic diagram obtained by extracting only the curve Cb from FIG.
- both the vertical and horizontal axes are logarithmic axes, the vertical axis represents amplitude level, and the horizontal axis represents frequency.
- the amplitude level at the frequency f21 is the largest at f3
- the amplitude level is the next largest
- the amplitude level at fl is the next largest.
- the number of frequencies to be selected as candidates is “3”
- all of the frequencies fl, f21, and f3 are candidate frequencies.
- the frequencies f21 and f3 are the candidate frequencies.
- the center frequency of the dip to be set in dip filter 4 may be determined based on the priority based on the magnitude of the amplitude level of curve Cb in FIG. Therefore, the number of dips to be set in the dip filter 4 in FIG. 1, for example, if it is “2”, the frequencies f21 and f3 are set as the center frequencies of the dips in the dip filter 4. Also, for example, if the number of dips to be set in dip filter 4 in FIG. 1 is “1”, only frequency f 21 is set as the center frequency of dips in dip filter 4.
- the priority order based on the magnitude of the amplitude level of the curve Cb in FIG. Although the center frequency of the dip to be set in the dip filter 4 may be finally determined, a plurality of dips to be set in the dip filter 4 are determined by the priority based on the magnitude of the amplitude level of the curve Cb in FIG. After selecting the center frequency candidate, based on the magnitude of the amplitude level in the curve Db in FIG. 5, the order of the candidates (candidate center frequency of the dip to be set in the dip filter) is also changed. Good,.
- the frequencies of these candidates are reordered.
- the order is set such that the amplitude level in the amplitude frequency characteristic curve Db in FIG.
- the frequencies fl, f21 and f3 have the highest amplitude level in the curve Db in FIG. 5
- the frequency f21 has the next highest amplitude level
- the frequency has the next highest amplitude level. Is the frequency fl. Therefore, the frequency f3 is the frequency of the first candidate, the frequency f21 is the frequency of the second candidate, and the frequency fl is the frequency of the third candidate.
- Numerical power of dip to be set in dip filter 4 of FIG. 1 for example, if “2”, frequency f3 and frequency f21 are set as the center frequency of dip in dip filter 4. Also, for example, if the dip power is “l” to be set in the dip filter 4 of FIG. 1, only the frequency f3 is set as the center frequency of the dip of the dip filter 4.
- the center frequency of the dip to be set in dip filter 4 can be objectively selected without requiring experience or skill. By doing so, resonance in the loudspeaker space 40 of FIG. 1 can be effectively prevented.
- the order of the candidates was changed based on the magnitude of the amplitude level for the following reason. That is, the curve Cb of FIG. 27 is not only characteristic by resonance of loud sound space 40, the electro-acoustic system (amplifier 12, speaker 13, microphone 14 Hitoshiryoku made system) and also include the amplitude frequency characteristic of, loud sound space 40 The characteristics greatly depend not only on the resonance characteristics of the above, but also on the amplitude frequency characteristics of the electroacoustic system.
- the above-described resonance frequency selection method is also effective when the number of dips to be set in the dip filter and the number of detected resonance frequencies are larger. For example, when the detected resonance frequency is 200 or more, 120 frequencies may be left as candidates from those having large amplitude levels in the curve Cb in FIG. 27, and the remaining frequencies may be excluded from the candidates. Further, based on the magnitude of the amplitude level in the curve Db of FIG. 5, the order of the candidates is rearranged with respect to the 120 frequencies, and the top eight frequencies are dip-filtered based on the rearranged order. And set it as the center frequency of the dip.
- the resonance frequency detection method and the device thereof according to the present invention are applied to the detection of the resonance frequency in the loudspeaker space in which the acoustic equipment is arranged.
- the device can be applied not only to such a loudspeaker space, but also to any space (resonant loudspeaker space) where resonance frequency detection is required.
- the present invention can also be applied to a technique of measuring the volume of a space not filled with liquid in a liquid tank by detecting a resonance frequency in order to know the liquid filling amount in the liquid tank.
- the present invention it is possible to accurately detect a resonance frequency without requiring experience or skill, and it is possible to appropriately select a frequency to be set as a center frequency of a dip in a dip filter. Therefore, for example, it is useful in the technical field of electroacoustics.
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Otolaryngology (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
- Circuit For Audible Band Transducer (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/568,300 US7965850B2 (en) | 2004-04-27 | 2005-04-26 | Resonance frequency determining method, resonance frequency selecting method, and resonance frequency determining apparatus |
EP05737289A EP1748674B1 (en) | 2004-04-27 | 2005-04-26 | Resonance frequency determining method, resonance frequency selecting method, and resonance frequency determining apparatus |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2004-131629 | 2004-04-27 | ||
JP2004131629A JP4209806B2 (ja) | 2004-04-27 | 2004-04-27 | 共鳴周波数検出方法、共鳴周波数選択方法、および、共鳴周波数検出装置 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2005104610A1 true WO2005104610A1 (ja) | 2005-11-03 |
Family
ID=35197387
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2005/007868 WO2005104610A1 (ja) | 2004-04-27 | 2005-04-26 | 共鳴周波数検出方法、共鳴周波数選択方法、および、共鳴周波数検出装置 |
Country Status (4)
Country | Link |
---|---|
US (1) | US7965850B2 (ja) |
EP (1) | EP1748674B1 (ja) |
JP (1) | JP4209806B2 (ja) |
WO (1) | WO2005104610A1 (ja) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2056624A1 (en) | 2008-04-10 | 2009-05-06 | Oticon A/S | Method of controlling a hearing device and hearing device |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2008093405A1 (ja) * | 2007-01-30 | 2008-08-07 | Toa Corporation | フィルタの周波数特性決定方法、および、共鳴防止装置 |
US20110183629A1 (en) * | 2010-01-26 | 2011-07-28 | Broadcom Corporation | Mobile Communication Devices Having Adaptable Features and Methods for Implementation |
US9331656B1 (en) * | 2010-06-17 | 2016-05-03 | Steven M. Gottlieb | Audio systems and methods employing an array of transducers optimized for particular sound frequencies |
KR102304694B1 (ko) * | 2014-10-28 | 2021-09-24 | 삼성전자주식회사 | 전자 장치 및 전자 장치의 방수 판단 방법 |
CN104390695A (zh) * | 2014-11-21 | 2015-03-04 | 广西智通节能环保科技有限公司 | 一种超声波测量系统 |
JP6957542B2 (ja) | 2019-03-18 | 2021-11-02 | 株式会社東芝 | 推定装置、推定方法 |
TWI749796B (zh) * | 2020-09-30 | 2021-12-11 | 瑞軒科技股份有限公司 | 共振測試系統及共振測試方法 |
KR20220130446A (ko) * | 2021-03-18 | 2022-09-27 | 삼성전자주식회사 | 외부 소리를 듣기 위한 전자 장치 및 전자 장치의 동작 방법 |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS60232797A (ja) * | 1984-05-04 | 1985-11-19 | Matsushita Electric Ind Co Ltd | スピ−カ装置 |
JPH06202671A (ja) * | 1993-01-06 | 1994-07-22 | Matsushita Electric Ind Co Ltd | 音響装置 |
JPH06265401A (ja) * | 1993-03-16 | 1994-09-22 | Nippon Telegr & Teleph Corp <Ntt> | 音響伝達特性等化装置 |
JPH07154467A (ja) * | 1993-11-29 | 1995-06-16 | Sanyo Electric Co Ltd | 音響装置 |
JPH08294194A (ja) * | 1995-04-21 | 1996-11-05 | Kawai Musical Instr Mfg Co Ltd | ハウリング防止装置及びハウリング防止機能付き電気・電子楽器 |
JP2000115883A (ja) * | 1998-09-30 | 2000-04-21 | Pioneer Electronic Corp | オーディオシステム |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2576423A (en) * | 1947-02-04 | 1951-11-27 | Gen Instrument Corp | Apparatus for determining resonant frequencies |
JPS5666919A (en) * | 1979-11-05 | 1981-06-05 | Nippon Columbia Co Ltd | Automatic corrector for sound field |
FR2485727A1 (fr) * | 1980-06-24 | 1981-12-31 | Snecma | Dispositif de mesure des frequences de resonnance des aubes de turbine, de compresseurs et de pales d'helices |
JPH0241004A (ja) * | 1988-08-01 | 1990-02-09 | Tdk Corp | 共振検出回路 |
JPH07143299A (ja) * | 1993-11-18 | 1995-06-02 | Canon Inc | ファクシミリ装置 |
JPH11127496A (ja) * | 1997-10-20 | 1999-05-11 | Sony Corp | ハウリング除去装置 |
DE10008937A1 (de) * | 2000-02-25 | 2001-08-30 | Philips Corp Intellectual Pty | Elektrischer Schaltkreis zur Ansteuerung von piezoelektrischen Antrieben |
JP3920226B2 (ja) * | 2002-12-09 | 2007-05-30 | ティーオーエー株式会社 | 共鳴周波数検出方法、共鳴周波数選択方法、および、共鳴周波数検出装置 |
-
2004
- 2004-04-27 JP JP2004131629A patent/JP4209806B2/ja not_active Expired - Lifetime
-
2005
- 2005-04-26 EP EP05737289A patent/EP1748674B1/en active Active
- 2005-04-26 WO PCT/JP2005/007868 patent/WO2005104610A1/ja active Application Filing
- 2005-04-26 US US11/568,300 patent/US7965850B2/en active Active
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS60232797A (ja) * | 1984-05-04 | 1985-11-19 | Matsushita Electric Ind Co Ltd | スピ−カ装置 |
JPH06202671A (ja) * | 1993-01-06 | 1994-07-22 | Matsushita Electric Ind Co Ltd | 音響装置 |
JPH06265401A (ja) * | 1993-03-16 | 1994-09-22 | Nippon Telegr & Teleph Corp <Ntt> | 音響伝達特性等化装置 |
JPH07154467A (ja) * | 1993-11-29 | 1995-06-16 | Sanyo Electric Co Ltd | 音響装置 |
JPH08294194A (ja) * | 1995-04-21 | 1996-11-05 | Kawai Musical Instr Mfg Co Ltd | ハウリング防止装置及びハウリング防止機能付き電気・電子楽器 |
JP2000115883A (ja) * | 1998-09-30 | 2000-04-21 | Pioneer Electronic Corp | オーディオシステム |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2056624A1 (en) | 2008-04-10 | 2009-05-06 | Oticon A/S | Method of controlling a hearing device and hearing device |
Also Published As
Publication number | Publication date |
---|---|
US7965850B2 (en) | 2011-06-21 |
JP4209806B2 (ja) | 2009-01-14 |
JP2005318094A (ja) | 2005-11-10 |
US20070180913A1 (en) | 2007-08-09 |
EP1748674A4 (en) | 2008-05-07 |
EP1748674A1 (en) | 2007-01-31 |
EP1748674B1 (en) | 2011-08-03 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
WO2005104610A1 (ja) | 共鳴周波数検出方法、共鳴周波数選択方法、および、共鳴周波数検出装置 | |
JP6326071B2 (ja) | 部屋およびプログラム反応型ラウドスピーカシステム | |
RU2419963C2 (ru) | Способ коррекции воспроизведения акустического сигнала электроакустическим преобразователем и устройство для его осуществления | |
JP3920233B2 (ja) | ディップフィルタの周波数特性決定方法 | |
JP3920226B2 (ja) | 共鳴周波数検出方法、共鳴周波数選択方法、および、共鳴周波数検出装置 | |
KR20190137710A (ko) | 스피커 장치의 작동 방법 및 스피커 장치 | |
WO2006093152A1 (ja) | 特性測定装置及び特性測定プログラム | |
CN113553022A (zh) | 设备调整方法、装置、移动终端及存储介质 | |
CN109862503B (zh) | 一种扬声器延时自动调整的方法与设备 | |
CN113424558A (zh) | 智能个人助理 | |
JP4376035B2 (ja) | 音響特性測定装置及び自動音場補正装置並びに音響特性測定方法及び自動音場補正方法 | |
US20050053246A1 (en) | Automatic sound field correction apparatus and computer program therefor | |
JP2006196940A (ja) | 音像定位制御装置 | |
JP4696142B2 (ja) | 共鳴周波数検出方法および共鳴周波数検出装置 | |
JP3901648B2 (ja) | ディップフィルタの周波数特性決定方法 | |
JPH08271627A (ja) | スピ−カ及びマイク間距離測定装置 | |
Mijić et al. | Reverberation radius in real rooms | |
JP2017143459A (ja) | 伝搬遅延特性の測定方法および装置 | |
JPH11262081A (ja) | 遅延時間設定方式 | |
JPH10294997A (ja) | 音声信号の処理回路および検査用装置 | |
CN110246516A (zh) | 一种语音通信中小空间回声信号的处理方法 | |
US11501745B1 (en) | Musical instrument pickup signal processing system | |
KR970004178B1 (ko) | 오디오 잔향음 부가 장치 | |
JPH05168087A (ja) | 音響装置及びリモコン | |
RU2297712C2 (ru) | Способ настройки звуковоспроизводящего тракта |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BW BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE EG ES FI GB GD GE GH GM HR HU ID IL IN IS KE KG KM KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NA NI NO NZ OM PG PH PL PT RO RU SC SD SE SG SK SL SM SY TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): BW GH GM KE LS MW MZ NA SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LT LU MC NL PL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
NENP | Non-entry into the national phase |
Ref country code: DE |
|
WWW | Wipo information: withdrawn in national office |
Country of ref document: DE |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2005737289 Country of ref document: EP |
|
WWP | Wipo information: published in national office |
Ref document number: 2005737289 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 11568300 Country of ref document: US Ref document number: 2007180913 Country of ref document: US |
|
WWP | Wipo information: published in national office |
Ref document number: 11568300 Country of ref document: US |