Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04S—STEREOPHONIC SYSTEMS 
  • H04S1/00—Two-channel systems
  • H04S1/002—Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R3/00—Circuits for transducers, loudspeakers or microphones
  • H04R3/02—Circuits for transducers, loudspeakers or microphones for preventing acoustic reaction, i.e. acoustic oscillatory feedback
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04S—STEREOPHONIC SYSTEMS 
  • H04S2400/00—Details of stereophonic systems covered by H04S but not provided for in its groups
  • H04S2400/13—Aspects of volume control, not necessarily automatic, in stereophonic sound systems

Definitions

• the present invention relates to a stereo sound image enlarging device applied to, for example, electronic devices, game machines, audio devices, and the like. Background technology>
• a technology has been developed in which the sound image is localized outside the left and right speakers by mixing opposite-phase sounds with the reproduced sound. With this technology, the stereo sound image can be enlarged, and the sound stage can be greatly expanded.
• the stereo sound image enlarging device disclosed in Japanese Patent Application Laid-Open No. Hei 9-168020 discloses a first operation unit that generates a difference signal by subtracting a second input signal from a first input signal.
• a filter unit that generates a filter difference signal by filtering the difference signal from the first arithmetic unit; and a second unit that generates a first output signal by adding the first input signal and the filter difference signal from the filter unit.
• the filter section consists of only a low-pass filter, a stereo sound source in which extremely low-frequency sounds, such as the bass sound of a musical instrument in a song or the sound of a pass drum, are recorded only by panning, Since the low-frequency difference signal is added to and subtracted from both the left and right channels, the low-frequency signal increases in volume and is more strongly panned, although it is easier for the listener to perceive. As a result, there is a problem that the tone becomes very uncomfortable. In particular, an increase in the volume of the low frequency band is a fatal problem in reproduction using a small speaker that cannot reproduce the low frequency band.
• Japanese Patent Application Laid-Open Publication No. H08-509094 (published patent publication) describes that the filter section is composed of a band-pass filter. As disclosed in Japanese Patent Application Laid-Open No. 09-104, it is as narrow as 300 Hz to 2 kHz, so that a natural reproduced sound cannot be obtained.
• a stereo sound image enlarging device includes: a first arithmetic unit that subtracts a second input signal from a first input signal to generate a difference signal; and filters and filters a difference signal from the first arithmetic unit.
• a third pass signal having a cut-off frequency of 5 kHz and a high-pass filter having a cut-off frequency of 20 OHz.
• the filter unit further includes a gain adjuster that limits the amplitude of the difference signal after the filtering by the one-pass filter and the high-pass filter.
• FIG. 1 is a block diagram showing a configuration of a stereo sound image enlarging system.
• FIG. 2 is a block diagram showing a configuration of the stereo sound image enlarging device of FIG.
• FIG. 3 is a graph showing a frequency characteristic of the one-pass filter of FIG.
• FIG. 4 is a graph showing frequency characteristics of the high-pass filter of FIG.
• Figure 5 is a graph showing the combined characteristics of a single-pass finolater and a no-pass filter.
• Fig. 1 shows the configuration of a stereo sound image expansion system using a stereo sound image expansion device.
• the stereo sound image enlargement system includes an external device 1, a stereo sound image enlargement device 2, a left speaker 3a, and a right speaker 3b.
• an electronic musical instrument, a game machine, an audio device or the like having a left channel signal and a right channel signal output terminal is used as the external device 1.
• the left channel input signal (first input signal) L in and the right channel input signal (second input signal) R in generated by the external device 1 are output to the stereo sound image enlarging device 2.
• the stereo sound image enlarging device 2 processes the left channel input signal L in and the right channel input signal R in to output a left channel output signal (first output signal) L out and a right channel output signal. (2nd output signal) R out is generated and output to the speeds 3a and 3b.
• FIG. 2 shows the configuration of the stereo sound image enlarging device 2.
• the input signal L in for the left channel from the external device 1 is supplied to the first arithmetic unit 4 and the second arithmetic unit 5.
• the right channel input signal R in from the external device 1 is supplied to the first arithmetic unit 4 and the third arithmetic unit 6.
• the first arithmetic unit 4 generates a difference signal SD by subtracting the right channel input signal R in from the left channel input signal L in.
• the first calculation unit 4 is configured by, for example, an operational amplifier, and when the left channel input signal L in is a digital signal, For example, it is composed of DSP or CPU.
• the difference signal SD output from the first calculation unit 4 is supplied to the filter unit 7.
• H The inoleter unit 7 includes a low-pass filter 8, a high-pass filter 9, and an amplitude adjuster 10.
• FIG. 3 shows the frequency characteristics of the low-pass filter 8
• FIG. 4 shows the frequency characteristics of the high-pass filter 9
• FIG. 5 shows the combined filter characteristics of the low-pass filter 8 and the high-pass filter 9, respectively.
• FIG. 5 (a) shows the synthesized frequency characteristics of the low-pass filter 8 and the high-pass filter 9
• FIG. 5 (b) shows the synthesized phase characteristics of the low-pass filter 8 and the high-pass filter 9, respectively.
• the low-pass filter 8 sets the cutoff frequency to 5 kHz, removes the high-frequency component of the difference signal SD from the first arithmetic unit 4, and outputs the first filter output signal SF1.
• the high-pass filter 9 sets the cut-off frequency to 20 OHz, removes the low-frequency component of the first filter output signal S F1 from the low-pass filter 8, and outputs a second filter output signal SF 2.
• the amplitude adjuster 10 multiplies the second filter output signal S F2 by a predetermined multiplication coefficient in order to output the filter difference signal S F3 while limiting the amplitude of the second filter output signal S F2.
• a known analog low-pass filter can be used as the filter unit 7.
• a digital filter including a delay element, a coefficient multiplier, and an adder can be used as the filter unit 7.
• the functions of the delay element, the coefficient multiplier, and the adder can be realized by the processing of the DSP or the CPU.
• this filter unit 7 for example, a primary IR digital one-pass filter with a cutoff frequency of 5 kHz, a primary IR digital high-pass filter with a power-off frequency of 200Hz, or the like can be used.
• the amplitude adjuster 10 When the second filter output signal SF2 is an analog signal, a device that adjusts the amplitude of the second filter output signal SF2 using a resistor or the like is used as the amplitude adjuster 10.
• the multiplication function of the amplitude adjuster 10 can be realized by DSP or CPU processing. This For example, a value from 0 to 1 can be used as a multiplication coefficient of the amplitude adjuster 10.
• a left channel input signal L in and a right channel input signal R in are input to the stereo sound image enlarging device 2 from an external device 1 such as a game machine.
• the left-channel input signal L i n input to the stereo sound image enlarging device 2 is input to the first arithmetic unit 4 and the second arithmetic unit 5.
• the input signal R in for the right channel input to the stereo sound image enlarging device 2 is input to the first arithmetic unit 4 and the third arithmetic unit 6.
• the first calculation unit 4 subtracts the input signal R in for the right channel from the input signal L in for the left channel and outputs a difference signal SD.
• the difference signal SD output from the first calculation unit 4 is input to the subsequent filter unit 7.
• the difference signal SD input to the filter unit 7 is filtered by the low-pass filter 8, and the first filter output signal S F 1 is output from the low-pass filter 8.
• the first filter output signal SF1 is filtered by the high-pass filter 9, and the high-pass filter 9 outputs the second filter output signal SF2.
• the second filter output signal S F 2 is sent to the amplitude adjuster 10.
• the amplitude of the second filter output signal SF2 is multiplied by a predetermined coefficient to limit the amplitude of the second filter output signal SF2, and a filter difference signal SF that is a result of the multiplication is multiplied. 3 is output from the amplitude adjuster 10.
• the filter difference signal S F3 output from the filter unit 7 is input to the second arithmetic unit 5 and the third arithmetic unit 6.
• the second arithmetic unit 5 adds the input signal L in for the left channel and the filter difference signal S F3, and outputs the addition result as an output signal L out for the left channel.
• the third arithmetic unit 6 subtracts the filter difference signal SF3 from the input signal R in for the right channel, and outputs the subtraction result as an output signal R out for the right channel.
• the output signal L out for the left channel output from the second arithmetic unit 5 is sent to the left speaker, not shown, and the output signal for the right channel output from the third arithmetic unit 6 R out is sent to a right speaker (not shown). This allows the listener to hear the enlarged sound image.
• the first input signal is the input signal R in for the left channel and the second input signal is the input signal R in for the right channel, but the first input signal is the input signal R in for the right channel. in, and the second input signal may be the left channel input signal L in.
• the first output signal is the right channel output signal Rout
• the second output signal is the left channel output signal Lout.
• the left and right channels are panned with the same phase or with a small phase difference (for example, bass and bass drum sounds), the left and right amplitude ratios are not changed and are emphasized. There is no sense of discomfort.

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Acoustics & Sound (AREA)
• Signal Processing (AREA)
• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Otolaryngology (AREA)
• Stereophonic System (AREA)

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Citations (2)

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• 1999
  • 1999-05-28 JP JP11150473A patent/JP2000341798A/ja active Pending
• 2000
  • 2000-05-25 KR KR1020017015211A patent/KR100563499B1/ko not_active IP Right Cessation
  • 2000-05-25 WO PCT/JP2000/003379 patent/WO2000074439A1/ja not_active Application Discontinuation
  • 2000-05-25 CN CN00808166A patent/CN1353917A/zh active Pending
  • 2000-05-25 EP EP00931572A patent/EP1189483A1/en not_active Withdrawn

Patent Citations (2)

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