JPH0644698B2 - Audio equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention comprises a tuner for receiving broadcasting, a cassette deck for recording and reproducing a musical tone signal using a cassette magnetic tape as a medium, and controls and amplifies an input signal from these signal sources. The present invention relates to a sound device that outputs sound from a speaker.

(Prior Art) When trying to listen to reproduced sound in a place where noise is generated in the surroundings, the reproduced sound may be interrupted by the noise due to an increase in noise level.

As an example, in a car stereo, even if the output volume is appropriately adjusted when the automobile is stopped, the reproduced sound may be difficult to hear due to an increase in the noise level inside the vehicle during traveling.

As an audio device that solves such a problem, conventionally, Service Weekly Report No. 4 issued by Nissan Motor Co., Ltd., September 1980.
28 (LP-1), pages 270 and 271. This audio system detects the ambient noise level, determines the switching position of the fan switch, and installs an automatic volume control circuit that automatically changes the output signal level of the amplifier according to these, increasing the ambient noise level. Even in such a case, the purpose of the circuit is to make it easier to hear the reproduced sound.

However, in such a conventional audio device, since the output sound level is only changed according to the noise level, it is possible to increase the output sound not only in the frequency band that is difficult to hear due to noise but also in the frequency band that is easy to hear. Therefore, there was a problem that the volume became too loud as a whole.

(Object of the Invention) In view of the actual situation of the conventional audio device, the present invention is such that when the ambient noise level rises and the output sound level relatively decreases,
The above problem is solved by using control means such as increasing the output level of the dynamic range of the musical tone signal in the frequency band that becomes difficult to hear as the noise level increases so that the output level becomes higher when the input level is lower. The present invention is intended to provide an audio device that does.

(Structure of the invention) For this purpose, the present invention is, in the audio device, a musical tone signal dividing means for dividing the musical tone signal into a plurality of frequency band components, and a noise level detecting means for detecting a surrounding noise level, A plurality of dynamic ranges that are provided independently for each frequency band, narrow the dynamic range of the musical tone signal by increasing the amplification degree when the musical tone signal level in the frequency band is low, and change the degree of narrowing. Changing means and dynamic range changing degree control means for increasing the extent to which the dynamic range changing means narrows the dynamic range in accordance with the increase in the noise level and independently for each of the dynamic range changing means. It is characterized by doing.

(Example) Hereinafter, the Example of this invention is described in detail based on drawing.

It is generally known that when the sound level is low, it is difficult to hear sounds in the low range and the high range, and FIG. 1 shows the present invention configured to achieve the above-mentioned purpose by paying attention to this point. 1 is a block diagram showing an embodiment of an audio device.

The output terminal of the cassette deck 1 for recording and reproducing the tone signal using the cassette magnetic tape as the recording medium and the output terminal of the tuner 2 for receiving the broadcast are respectively connected to the input terminals of the preamplifier 3, and the output terminal of the preamplifier 3 is the tone signal. It is connected to the input terminal of the channel divider 4 as a dividing means. In addition, this channel divider 4
Is a three-channel divider that divides a pass frequency band into 500 Hz or less and 500 Hz or more, less than 5 kHz and less than 5 kHz and 5 kHz or more, for example, with crossover frequencies of 500 Hz and 5 kHz. Also, the three output terminals of the channel divider 4 of 500 Hz or less, more than 500 Hz and less than 5 kHz, and 5 kHz or more are connected to the tone signal input terminals of the dynamic range controllers 5, 6 and 7 as the dynamic range changing means, respectively, and these dynamics are connected. The range controllers 5, 6 and 7 keep the output level constant when the input signal is at a high level and change the output level when the input signal is at a low level in accordance with the control signal level described later to control the dynamic range of the output signal. Shall be controlled.

The microphone 8 is connected to the input terminal of a noise detection circuit 9 that constitutes noise level detection means together with the microphone 8, and the output terminal of the noise detection circuit 9 is connected to the input terminal of the control signal generation circuit 10. Control signal generation circuit 10 and multiplication circuits 11, 12, 13
Is equivalent to the dynamic range change degree control means, and the output terminal of the control signal generation circuit 10 uses the constant a,
Multiplier circuits 11 and 1 for multiplying and outputting b and c, respectively
2 and 13 are respectively connected to the input terminals of the multiplication circuits 11 and 1
The output terminals of 2 and 13 are connected to the control signal input terminals of the corresponding dynamic range controllers 5, 6 and 7, respectively.

In addition, the dynamic range controller 5, 6, 7
The output terminals of are connected to the input terminals of the mixer 14 that mixes the three types of signals from them, and the output terminals of the mixer 14 are connected to the input terminals of the main amplifier 16 via the volume 15 and The output terminal is connected to the speaker 17.

The operation of the above embodiment will be described below.
And, the tone signal from the tuner 2 is selected by the preamplifier 3 and is amplified, and the channel divider 4 is 500Hz or less, 500Hz or more and 5kHz.
Less than 5kHz and output as 3 types of frequency band signals, respectively, dynamic range controller 5, 6, 7
To enter. Dynamic range controller 5,
The frequency band signals from 6 and 7 are mixed again in the mixer 14, adjusted in level through the volume 15, amplified by the main amplifier 16, and reproduced and output as sound from the speaker 17.

When the ambient noise level rises, the microphone 8 sends a noise signal to the noise detection circuit 9, and the noise detection circuit 9 drives the control signal generation circuit 10 to generate an acoustic control signal according to the noise signal level. The acoustic control signal is applied to the multiplication circuits 11, 1
2 and 13 are input respectively, and the multiplication circuit 11 multiplies them by a to give them to the dynamic range controller 5, while the multiplication circuit 12 multiplies them by b to give them to the dynamic range controller 6, and the multiplication circuit 13 gives c. The result is multiplied and given to the dynamic range controller 7. If, for example, a = 3, b = 1, c = 2 are set, the dynamic range controllers 5, 6, 7 are shown in the operating characteristic diagrams (a), (b), (c) of FIG. 2, respectively. As described above, when the noise signal level is low, the output level is determined with the input / output characteristic shown by the solid line, and the output level is determined with the characteristic shown by the broken line according to the rise of the noise signal level. Therefore, as the noise signal level rises, each of the dynamic range controllers 5 to 7 approaches a characteristic in which the degree of amplification at the time of a small input is increased.

Therefore, the audio device according to the first embodiment has a noise level of the surroundings as shown in the frequency-output level characteristic diagram of FIG. 3 when the tone signal level is high (d) and when it is low (e). When the noise level is low, the frequency characteristic of the output sound is flat as shown by the solid line regardless of the tone signal level, and when the surrounding noise level rises and the output sound level relatively decreases, the frequency characteristic of the output sound is shown by the broken line. The bass and treble are raised. Further, the lower the tone signal level, the higher the rate of increase in the output sound level of the bass portion and the treble portion.

FIG. 4 is a block diagram showing another embodiment of the present invention, in which the same parts as in FIG. 1 are designated by the same reference numerals.

In the present embodiment, the above-described object is achieved by focusing on the point that reproduced sound of a frequency corresponding to the frequency of ambient noise is blocked and becomes difficult to hear.
Therefore, in this example, as the dynamic range change degree control means, the control signal generation circuit 10 and the multiplication circuits 11 to 13 in the first embodiment are replaced by a frequency corresponding to the crossover frequency of the channel divider 4. The channel divider 18 to be divided and the control signal generating circuits 19 to 21 for respectively generating the acoustic control signals according to the signal levels of the three types of noise signals output from the channel divider 18 are provided, and these are designated as the noise detection circuit 9. It is inserted between the dynamic range controllers 5 and 7.

Therefore, the noise detection circuit 9 drives the control signal generation circuits 19, 20, and 21 via the channel divider 18 in response to the noise signal from the microphone 8, and the three kinds of musical tone signals divided by the channel divider 4 are generated. An acoustic control signal corresponding to the frequency band is generated. Therefore, the dynamic range controllers 5, 6 and 7 narrow the dynamic range of only the signals in the frequency band of the musical sound signal that are difficult to hear because they are blocked by the surrounding noises. The rate of increase of the level can be high.

(Effects of the Invention) Thus, in the audio device of the present invention, the dynamic range changing degree control means determines the extent to which the dynamic range changing means narrows the dynamic range based on the noise level detected by the noise level detecting means in accordance with the increase in the noise level. Moreover, since the dynamic range changing means is configured to increase independently, it is particularly suitable for a frequency band that is difficult to hear due to noise when the surrounding noise level rises and the output sound level relatively decreases. With emphasis, the degree to which the dynamic range is narrowed so that the output level becomes higher when the tone signal level is lower can be increased in accordance with the increase in the noise level, so that the frequency band becomes difficult to hear due to noise. The output sound of the is as natural as the noise level rises when the tone signal level is low. Therefore, it is possible to make the output sound easier to hear without increasing the overall volume too much and with a natural feeling.

(Effects of Embodiment) Further, if configured as in another embodiment shown in FIG. 4,
Since the dynamic range is narrowed only to the frequency band blocked by noise, the effects of the first embodiment can be more naturally heard.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of an audio device of the present invention, FIG. 2 is an operation characteristic diagram of a dynamic range controller of the same device, FIG. 3 is a frequency-output characteristic diagram of the device, and FIG. The figure is a block diagram showing another embodiment of the present invention. 1 ... Cassette deck, 2 ... tuner 3 ... preamplifier, 4 ... channel divider 5, 6, 7 ... dynamic range controller 8 ... microphone, 9 ... noise detection circuit 10 ... control signal generation circuit, 11,12,13 …… Multiplier circuit 14 …… Mixer, 15 …… Volume 16 …… Main amplifier, 17 …… Speaker 18 …… Channel divider, 19,20,21 …… Control signal generation circuit.

Claims (1)

[Claims] 1. A sound device capable of reproducing a tone signal as a sound, comprising: a tone signal dividing unit for dividing the tone signal into a plurality of frequency band components; and a noise level detecting unit for detecting a noise level in the surroundings. Multiple dynamic range changes that are provided independently for each frequency band and narrow the dynamic range of the tone signal by increasing the amplification degree when the tone signal level in that frequency band is low, and can change the degree of narrowing Means and a dynamic range change degree control means for increasing the degree to which the dynamic range change means narrows the dynamic range in response to the increase in the noise level and independently for each of the dynamic range change means. An acoustic device characterized by the above.