JPH09148867A - On-vehicle acoustic reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compensate the level of an audio signal so that the sense level of a listener may be almost the same as the level when noise does not exist when running noise, etc., exists within a compartment. SOLUTION: The frequency characteristic of a noise signal is analyzed by a frequency component analysis means 3 and a compensation level setting means 4 according to the frequency band sets the compensation amount of the sense level for every frequency band. Based on the setting, a characteristic change means 5 according to the frequency band changes the frequency characteristic of an audio signal in which a CD, etc., is defined as a source and compensate the sense level. The compensated audio signal is reproduced from a speaker after the signal is amplified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-vehicle sound reproducing apparatus for reproducing audio by compensating for noise in a vehicle compartment so that the listening characteristic becomes optimum.

[0002]

2. Description of the Related Art FIG. 3 shows a configuration of a noise compensation portion in a conventional vehicle-mounted sound reproducing device. In FIG. 3, reference numeral 1 is a source signal input terminal, which is a terminal for inputting signals such as a CD and a cassette tape. Reference numeral 2 denotes a noise signal input terminal, which is a terminal for inputting the noise in the vehicle compartment picked up by a microphone as an electric signal. 11 is a noise level detection means,
It is connected to the noise signal input terminal 2. Reference numeral 12 is a volume setting means, which is connected to the noise level detecting means 11. 13
Is a volume adjusting means, which is connected to the source signal input terminal 1 and the volume setting means 12. An audio signal output terminal 6 is connected to the volume adjusting means 13.

Next, the operation of the conventional example having the above configuration will be described. For the noise signal input from the noise signal input terminal 2, the noise level detecting means 11 detects the average noise level or the noise peak level, and the volume setting means 12 is notified of the information. The volume setting means 12 sets the volume suitable for listening according to the notification from the noise level detecting means 11, and notifies the volume adjusting means 13 of the set value.

On the other hand, an audio source signal sent from a CD deck, a cassette deck, a radio receiving means, etc. is inputted from a source signal input terminal 1. Volume control means 13
According to the notification from the volume setting means 12, the volume of the source signal sent from the source signal input terminal 1 is adjusted and sent to the audio signal output terminal 6. Audio signal output terminal 6
The audio signal output from is amplified by an audio amplifier and then reproduced by a speaker.

As described above, even in the above-described conventional vehicle-mounted sound reproducing apparatus, it is possible to increase the volume of an audio signal that is difficult to hear due to noise in accordance with the noise level and make it easier to hear.

[0006]

However, the frequency characteristic of vehicle interior noise is generally characterized by a large level in the low range and a decrease in the high range. Therefore,
In the above-mentioned conventional example, when changing the volume of the audio signal according to the noise level, if the volume to be increased is set high, the volume is increased to the high-frequency audio signal at a sufficiently audible level, and conversely if the volume to be increased is set low, There is a problem that low frequency audio signals cannot be heard. In addition, in order to detect the noise characteristics of the listener's binaural position, it is necessary to install a microphone near the listener's binaural position, and there is also the problem that the in-vehicle sound reproduction device and the microphone must be installed separately. there were.

The present invention solves the problems of the prior art as described above, and a first object of the present invention is to provide audio according to the frequency characteristic of noise so that the listener's sense level does not change due to noise. An object of the present invention is to provide a vehicle-mounted sound reproduction device that compensates for frequency characteristics of a signal. A second object of the present invention is to provide a vehicle-mounted sound reproducing device that collects sound with a microphone built in the vehicle-mounted sound reproducing device and estimates and compensates for noise characteristics at the positions of both ears of the listener.

[0008]

The on-vehicle sound reproducing apparatus of the present invention for achieving the first object has a frequency component analyzing means for analyzing the frequency characteristic of noise and a sense level for each frequency band. Frequency band-based compensation level setting means for setting the compensation amount of, and frequency band-based characteristic changing means for changing the frequency characteristic of the audio signal,
The frequency characteristic of an audio signal is changed according to the frequency characteristic of noise.

According to the above arrangement, since the frequency characteristic of the audio signal is changed according to the frequency characteristic of noise, the listener's sense level can always be kept at a constant level.

In addition, the vehicle-mounted sound reproducing device of the present invention for achieving the above-mentioned second object has the above-mentioned structure and further includes a noise collecting device incorporated in the vehicle-mounted sound reproducing device for collecting noise in the vehicle interior. A sound microphone and a microphone characteristic compensating means for compensating the amplitude frequency characteristic of the detected noise signal are provided, and the noise characteristic of the listener's ear position is estimated from the noise signal of the built-in microphone to estimate the amplitude frequency of the noise signal. The characteristic is compensated.

[0011]

Embodiments of the present invention will be described below in detail. (Embodiment 1) FIG. 1 shows Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 is a source signal input terminal to which an audio source signal such as a CD, a cassette tape or a radio is input. Reference numeral 2 denotes a noise signal input terminal for inputting, as an electric signal, noise in the vicinity of the listener's binaural position, which is picked up by a microphone or the like installed near the listener's binaural position. Reference numeral 3 is a frequency component analyzing means, which is connected to the noise signal input terminal 2. Reference numeral 4 is a compensation level setting means for each frequency band, which is connected to the frequency component analyzing means 3. Reference numeral 5 is frequency band-specific characteristic changing means, which is connected to the frequency band-specific compensation level setting means 4 and the source signal input terminal 1. An audio signal output terminal 6 is connected to the frequency band-specific characteristic changing means 5. Reference numeral 7 is a sensory level compensating unit that includes the frequency component analyzing unit 3, the frequency band-based compensation level setting unit 4, and the frequency band-based characteristic changing unit 5.

Next, the operation of the first embodiment will be described. First, the noise signal input from the noise signal input means 2 is analyzed by the frequency band component analysis means 3 for amplitude frequency characteristics, and the information for each set frequency band is sent to the frequency band compensation level setting means 4. Be notified. The frequency band-specific compensation level setting means 4 sets the compensation level so that the listener's sense level becomes a constant level for each frequency band according to the notification from the frequency component analyzing means 3, and the frequency band-specific characteristic changing means 5 is set. Notice. Audio source signals such as a CD, a cassette tape, and a radio are input to the source signal input terminal 1 and sent to the frequency band-specific characteristic changing means 5. The characteristic changing means 5 for each frequency band is
In accordance with the notification from the frequency band-based compensation level setting means 4, the characteristics of the source signal sent from the source signal input terminal 1 are adjusted for each frequency band and sent to the audio signal output terminal 6. The audio signal whose frequency characteristic has been changed is sent from the audio signal output terminal 6 to the audio amplifier, amplified, and then reproduced from the speaker.

Here, a brief description of the sense level will be given. The sense level is defined by the difference between the input sound pressure level and the minimum audible level in the band in the amplitude frequency characteristic when a certain acoustic signal is presented. FIG.
Is an example showing the sensation level when there is no noise, and shows the case where a certain music signal is presented with the amplitude frequency characteristic shown by the solid line and the minimum audible level is the dotted line. The sense level when there is no noise is represented by the shaded area in FIG. However, the sensation level may be the difference between the input sound pressure level and the minimum audible level of the band multiplied by a constant in the amplitude frequency characteristic when a certain acoustic signal is presented.

FIG. 5 shows a case where noise exists with the amplitude-frequency characteristic represented by a broken line, and the sense level at that time is as shown by the shaded area in FIG. 5, and compared with the case where there is no noise. And the sense level decreases. Therefore, in order to compensate for this decrease in the sense level, the frequency characteristic of the music signal is changed by the compensation level in FIG.

The frequency band-specific compensation level setting means 4 in FIG. 1 sets the compensation level shown in FIG. 6 for each frequency band, and the frequency band-specific characteristic changing means 5 sets the frequency characteristics of the source signal by the compensation level. To change.

As described above, according to the first embodiment, since the frequency characteristic of the audio signal can be changed according to the frequency characteristic of noise, there is an effect that the listener's sense level can be kept constant. .

(Embodiment 2) FIG. 2 shows Embodiment 2 of the present invention, in which the same reference numerals as those in FIG. 1 represent the same things, and 8 indicates noise collection. Microphone 9 is a microphone characteristic compensation means. The noise pickup microphone 8 is built in the in-vehicle sound reproducing device and collects noise in the vicinity of the in-vehicle sound reproducing device main body and converts it into an electric signal. The microphone characteristic compensating means 9 is for compensating the amplitude-frequency characteristic in which the noise characteristic in the vicinity of the listener's ear position is estimated from the noise signal picked up by the noise pickup microphone 8. The sensory level is compensated by using a noise signal near the ear position.

Therefore, as in the first embodiment, since the frequency characteristic of the audio signal can be changed according to the frequency characteristic of noise, there is an effect that the sense level of the listener can be made constant, and the vehicle-mounted type can be used. Since the noise signal is picked up by the microphone built in the main body of the audio device, the structure of the device can be simplified.

[0019]

As described above, according to the present invention,
Since the frequency characteristic of the audio signal can be changed according to the frequency characteristic of noise, the listener's sense level can be maintained at a constant level.

Further, since the noise signal is picked up by the microphone built in the on-vehicle audio device main body, there is an effect that the structure of the device can be simplified.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a vehicle-mounted sound reproduction device according to a first embodiment of the present invention.

FIG. 2 is a schematic block diagram of a vehicle-mounted sound reproducing device according to a second embodiment of the present invention.

FIG. 3 is a schematic block diagram of a conventional example.

FIG. 4 is a diagram showing an example of a sense level when there is no noise.

5 is a diagram showing an example of a sense level when noise is added to the sense level of FIG.

FIG. 6 is a diagram showing an example of a sense level in which the sense level of FIG. 5 is compensated.

[Explanation of Codes] 1 ... Source signal input terminal, 2 ... Noise signal input terminal, 3 ... Frequency component analyzing means, 4 ... Frequency band-specific compensation level setting means, 5 ... Frequency band-specific characteristic changing means, 6 ... Audio signal output Terminal, 8 ... Noise pickup microphone, 9 ... Microphone characteristic compensation means.

Claims (6)

[Claims] 1. Compensating an audio signal level so that the listener's sense level is substantially the same when noise is present and when it is not provided with a means for capturing noise in the vehicle interior and a sense level compensating means. An on-vehicle sound reproducing device characterized by being. 2. The sensory level compensating means comprises frequency component analyzing means, frequency band-specific compensation level setting means, and frequency band-specific characteristic changing means, analyzes the frequency components of noise, and analyzes each frequency band. The in-vehicle sound reproducing device according to claim 1, wherein the audio signal level is compensated. 3. The on-vehicle sound reproducing device according to claim 1, wherein the sensation level is a difference between a constant multiple of the minimum audible level when there is no noise and the music signal level. 4. A microphone characteristic compensating means for changing the frequency characteristic of the microphone signal is provided.
Alternatively, the vehicle-mounted sound reproducing device according to the above item 3. 5. The microphone characteristic compensating means estimates and compensates for noise at the positions of both ears of the listener.
5. The vehicle-mounted sound reproducing device according to any one of items 1 to 4. 6. The on-vehicle sound reproducing device according to claim 1, wherein the input signal of the microphone characteristic compensating means is a microphone signal attached to the audio main body.