JPS61248611A - Loudness compensation device - Google Patents

Abstract

PURPOSE:To obtain natural sound quality by providing a compensation circuit to a loudness compensation device and giving a compensation nearly equal to the difference between a shape of a reference curve and a shape of a curve on an equi-sensing curve to a listening loudness with respect to the equi-sensing curve to a specific loudness. CONSTITUTION:Suppose that a mean loudness level of a monitor by a mixer operator is, e.g., 100 phon in forming a music source, when a curve on the equi-sensing curve corresponding to the said loudness is extracted and drawn, the shape is as shown in X in figure. On the other hand, suppose that the mean loudness level reproduced and listened to from the said music source is 70 phon, the curve on the equi-sensing curve corresponding to the loudness is extracted and the shape Y is overlapped on the curve corresponding to 100 phon mentioned above as shown in figure, then it is known that there is a difference between the shapes X and Y as shown in hatched lines in figure. Thus, in order to obtain the equal sound quality as the listening by the mixer operator while monitoring in forming the music source, the said difference has only to be compensated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a loudness compensator that compensates for perceptual frequency characteristics when listening to a low volume.

[Prior art and its problems]

As shown in Figure 6, the loudness compensation amount of conventional devices of this type has a shape that mimics the isosensory (equal loudness) curve itself at low volumes. In the case of sound heard from a source, etc., the amount of compensation is too large, resulting in unnatural sound quality.

That is, if we consider how commercially available music sources are created, in most cases recording is done by multi-trunk recording using multi-microphones.

Next, after using effectors, etc., it is mixed down to a two-channel stereo format. At this time, the mixer operator makes the final decision while listening to the source sound at the loudness level using a monitor playback device in the mixing room. to determine the sound quality of the music source. At this time, let us assume that the average loudness of the music that the mixer operator is listening to is 100 phons.

Next, considering the listener who purchases and plays the music source created as described above, the listener uses the volume adjuster of the playback device to adjust the volume to his or her preference.

In many cases, the average listening sound pressure on the playback side is lower than the sound pressure heard by the mixer operator, so let us assume that the average loudness on the playback side is 70 phon.

By the way, there is a so-called Robinson-Daso 1-Son curve as shown in FIG. 7 as a pure tone magnitude line. Looking at the curve, the shape of the curve is different when the loudness is 100 phon and when the loudness is 70 phon.
When using a phono, the increase in sound pressure level at low frequencies, that is, the decrease in ear sensitivity, is relatively gradual;
It can be seen that the increase is quite rapid in Hong Kong. This means that the sound quality of music played at a low volume is not equal to the sound quality as determined by the mixer operator.
It can be seen that it sounds as if the level of the low range or high range has decreased.

[Purpose of the invention]

The present invention has been made in order to eliminate the above-mentioned drawbacks of the conventional devices, and an object of the present invention is to provide a loudness compensation device that can provide appropriate compensation and obtain natural sound quality.

[Summary of the invention]

The loudness compensation device according to the present invention compensates for the reduction in the loudness of the low or high frequencies relative to the midrange when listening to a low volume, and is compatible with a specific loudness level of a monitor by a mixer operator when creating a music source, etc. A natural sound quality is obtained by using the curve on the contour line as a reference and providing a compensation amount approximately equal to the difference between the shape of the reference curve and the shape of the curve on the contour line with respect to listening loudness.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

Currently, the average loudness level of monitors by mixer operators when creating music sources, etc. is 10.
Assuming that the loudness is 0 phon, if the curve on the isobedient line in FIG. 7 corresponding to the loudness is taken out and drawn, its shape will be as shown by X in FIG. 1. On the other hand, if the average loudness level at which the same music source is reproduced and listened to is 70 phon, then the curve on the isobright line in Fig. 7 corresponding to the loudness is extracted and its shape Y is as shown in Fig. 1. When superimposed with the curve corresponding to the 100 phons above, we get
It can be seen that there is a difference between shapes X and 7 as shown by diagonal lines.

Therefore, in order to obtain a sound quality equivalent to that heard by a mixer operator on a monitor when creating a music source, etc., it is sufficient to compensate for the above-mentioned difference.

In general, when adjusting the volume using a volume adjuster, the average loudness of the music being played is given by the difference between the shape of the standard isobaric line and the shape of the loudness curve corresponding to the above-mentioned playback loudness. The amount of compensation provided changes. Therefore, by performing such compensation according to the adjustment position of the volume adjuster, the transfer function including the speaker characteristics and sound field characteristics in the mixing room where the music source, etc. is created, and the playback and listening of the music source, etc. If the speaker characteristics in the environment, the sound field characteristics, or the transfer function including the characteristics of the amplifier for correcting the sound field are both approximately flat, the mixer operator can easily monitor the sound even if the playback volume changes. You can listen to music with the same sound quality as the one you played.

The loudness compensation described above may have a circuit configuration similar to that of a conventional compensation circuit even if the circuit constants are different.
This can be easily realized by a circuit as shown in Figures (a) and (bl). In Figure 2 (a), one intermediate tap 14C is connected between the input 14a of the volume VR as a volume adjuster and the ground end 14b. are provided, and capacitors C, CZ are provided between the input terminal 21a and the ground terminal 21b.
and a resistor R1 are connected in series, and a capacitor (
, +, and Ct are connected to the intermediate tap 14C and to the ground end 21b via a resistor R2, and the movable element of the volume VR is connected to the output terminal 21C.

In FIG. 2(b), the volume VR is provided with three intermediate taps 14C'~l4C///, and each intermediate tap has a capacitor C,/~C,///, C2/~C.
2″′ and resistance R, /~R, /// , R2/~R2
Compensation circuits respectively configured by /// are connected.

Note that since the amount of compensation in the high range is small, the same effect can be obtained by omitting C1 in Figure 2 fal and C, /~C, /// in Figure 2 (bl) and compensating only the low range. It will be done.

By the way, as mentioned above, since the amount of compensation is changed according to the adjustment of the volume VR, it is important to correspond between the rotation angle of the polygon VR and the listening loudness. The gain of the amplifier after VR, the efficiency of the speakers, the number of speakers, and the state of the sound field affect the volume of the playback device such as VR. Among these, things other than the sound field can be defined as the characteristics of the acoustic device, and the transfer characteristics within the sound field can be roughly defined by limiting the use of the acoustic device to, for example, in-vehicle use or home use. It is possible to realize the loudness compensation device described above.

Figure 3 shows an example of the amount of compensation when the loudness determined by the mixer operator when creating a music source is set to 100 phons, and the figure shows that as the playback level decreases, the amount of compensation for low frequencies increases. I know that there is.

FIG. 4 is a block diagram showing an example of an in-vehicle audio device equipped with the above-mentioned loudness compensator. Preamplifier 13 via rear selector switch 12
, where it is preamplified and the volume adjuster 14.
After the volume is adjusted by the sound field correction device 15 and the sound field is corrected by the sound field correction device 15, the power amplifiers 18a to 18a corresponding to the respective speakers 168 to 16C provided in the sound field 17a of the vehicle 17
is applied to In addition, the speaker 16C is a super bass speaker, and a low-pass filter 19 is installed in front of the power amplifier 18C.
has been inserted. Further, 20 is a CD amplifier which is switched and used by a changeover switch 12.

The volume adjuster 14 is provided with a loudness compensation device 21 constructed according to the present invention.

FIG. 5 shows an example of a loudness compensator that obtained favorable results when applied to the in-vehicle audio device described above with reference to FIG. , C2 has a capacity of 0.0
8μF capacitor, R+, R2, R3 are 1.8Ω and 2.2Ω respectively.

It is a 50Ω resistor.

Although not specifically mentioned in the above embodiment, the frequency range for loudness compensation needs to be at least 40 to 10 KHz, which affects the audible range of the audio device.

Further, the loudness compensation amount does not necessarily have to be equal to the difference between the shape of the reference curve and the shape of the arbitrary curve, and there is no problem even if the difference is within ±3 dB.

Furthermore, in the example, a loudness compensation device added to a variable resistance type volume adjuster is shown, and the amount of compensation is changed continuously depending on the angle of the volume, but several fixed loudness compensation curves are averaged. The same effect as described above can also be obtained by automatically switching according to changes in listening loudness.

〔Effect of the invention〕

As explained above, according to the present invention, the compensation amount of loudness compensation is set to be approximately equal to the difference between the shape of the reference loudness curve and the shape of the loudness curve of other levels, with the loudness curve of a specific level as a reference. Therefore, regardless of the playback volume, you can listen to the playback sound with the same quality as when the music source was created.

[Brief explanation of drawings]

FIG. 1 is a graph for explaining how loudness is compensated in the device according to the present invention, FIG. 2 is a circuit diagram showing a circuit example of the loudness compensation device, and FIG. 3 is the amount of loudness compensation for each loudness in the device according to the present invention. 4 is a block diagram showing an example of an audio device to which the device according to the present invention is applied. FIG. 5 is a circuit diagram showing a specific example of a loudness device suitable for the audio device of FIG. 4. FIG. 6 is a graph showing the loudness compensation characteristics of the conventional device, and FIG. 7 is a graph showing an example of the iso-corrosion line. Patent applicant: Pioneer Corporation r, o-

Claims (1)

[Claims] In a loudness compensation device that compensates for audible frequency characteristics when listening to a low volume, a curve for a specific loudness on an iso-sensory curve is used as a reference, and the shape of the reference curve and the iso-sensitivity for the audible loudness are determined. A loudness compensation device comprising a compensation circuit that provides a compensation amount approximately equal to the difference between the shape of the curve and the shape of the curve.