JP4750153B2 - Acoustic device and acoustic adjustment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To propose an acoustic device and an acoustic adjustment method, for playing back in excellent sound quality according to user's auditory characteristics. <P>SOLUTION: In an auditory detection section 2b, a sound pressure level is gradually raised for each detection sound of each frequency band, and the sound pressure level at which the user can hear the detection sound is determined as a perception sound pressure level for each frequency band, according to timing of receiving a confirmation signal from a confirmation signal input section 10. Thereby, the acoustic processing section 2a easily determines where the specified frequency band which is hard to listen for the user is, or is not, from sound pressure difference between perception sound pressure level and a reference sound pressure level, and surely amplifies the sound pressure level in only the frequency band which is hard to listen for the user, by amplifiers 5a, 5b, 5c and so on, which are respectively provided for each frequency band, and consequently, music is adjusted to the sound pressure level which is easy to listen for the user in all frequency bands and played back in the excellent sound quality according to the user's auditory characteristics. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an acoustic device and an acoustic adjustment method, and is preferably applied when, for example, an analog signal is generated by interpolating between discrete data arranged in a time direction sampled at a predetermined sampling frequency.

2. Description of the Related Art Conventionally, in an audio device, for example, when playing a recording medium such as a CD (Compact Disc) or a DVD (Digital Versatile Disc), the volume output from the speaker is increased by operating the volume control. Even if the user is a deaf or elderly person, the reproduced sound can be easily heard (see, for example, Patent Document 1).
JP 2004-260518 A

  However, even if it is a hearing-impaired person or an elderly person, not all frequency bands are difficult to hear, and only a specific frequency band may be difficult to hear. In such a case, if the volume is simply increased, the volume of the frequency band that is easy to hear increases, and it becomes difficult to hear other frequency bands, resulting in a problem that the sound quality is deteriorated. Therefore, it is desired to be able to adjust the sound quality suitable for the user's auditory characteristics according to each user's auditory characteristics, the type of music, and the like.

  The present invention has been made in consideration of the above points, and an object of the present invention is to propose an acoustic apparatus and an acoustic adjustment method that can be reproduced with good sound quality according to the user's auditory characteristics.

In order to solve this problem, an audio device according to claim 1 of the present invention specifies a perceived sound pressure level, which is a minimum sound pressure level detected by a user, for each frequency band, and tests an auditory characteristic of the user. means, music to be listened to by the user is inputted from the input unit as an acoustic signal, adjusting the frequency characteristic of the acoustic signal, the frequency characteristics suitable for the hearing characteristics of the user based on the output result from the hearing test device The auditory test means stores a statistical standard sound pressure curve representing a minimum sound pressure level heard by a general user for each frequency band, and the standard sound pressure curve. A sound pressure coefficient, which is a ratio between the standard sound pressure level of the sound and the perceived sound pressure level, is calculated for each frequency band examined by the user, and the sound pressure coefficient and the frequency band between the examined frequency bands Relationship with Generates, that infer perceived sound pressure level trend based on the plurality of the relational equation, the sound pressure level of the frequency band of the user listening difficult the acoustic signal from the speculative result and amplified by the adjusting means It is characterized by.

The acoustic apparatus according to claim 2 of the present invention, the hearing test device until there is a response from the user to the test sound, to the user while increasing the sound pressure level of the test sound for each frequency band comprising: a test sound output means for presenting the test sound, and a specifying means for specifying the perceived sound pressure level by Ri for each of the frequency bands in response from the user, said adjustment means, the inputted acoustic signal A band separation unit that separates the frequency band into a plurality of frequency bands, and for each of the frequency bands separated by the band separation unit, the sound pressure level of the frequency band that is difficult for the user to hear is increased or decreased based on the estimation result. Features.

According to a third aspect of the present invention, in the audio device according to the third aspect of the present invention, the auditory inspection unit is configured to use a frequency band other than the frequency band in which the perceived sound pressure level is specified based on a relational expression between the sound pressure coefficient and the frequency band. And generating means for generating a perceptual sound pressure curve indicating the perceived sound pressure level tendency of the entire frequency band by calculating the user-specific perceived sound pressure level tendency, and the adjusting means includes the perception The sound pressure level is increased or decreased for each of the frequency bands based on a sound pressure curve.

  The acoustic device according to claim 4 of the present invention is characterized in that the perceived sound pressure curve is represented by an nth order polynomial relating to frequency, and a sound pressure adjustment level at each frequency is generated based on the nth order polynomial.

  The acoustic device according to claim 5 of the present invention is characterized in that a plurality of the perceptual sound pressure curves generated in advance are stored in the auditory test means.

  Moreover, the acoustic device according to claim 6 of the present invention includes a selection unit for causing a user to select a desired perceived sound pressure curve among the plurality of perceived sound pressure curves stored in the auditory examination unit. It is characterized by.

  The sound device according to claim 7 of the present invention is characterized in that the inspection sound output means includes a minute sound generating means for generating a minute sound for an auditory characteristic inspection, and the user when the user perceives the minute sound. And a confirmation signal input means for inputting a confirmation signal.

In the acoustic adjustment method according to claim 8 of the present invention, the perceptual sound pressure level, which is the minimum sound pressure level detected by the user, is specified for each frequency band by the hearing test means, and the user's auditory characteristics are tested. A standard sound pressure level of the standard sound pressure curve by the auditory test step and the auditory test means storing a statistical standard sound pressure curve representing a minimum sound pressure level heard by a general user for each frequency band; And a calculation step of calculating a sound pressure coefficient, which is a ratio to the perceived sound pressure level, for each frequency band examined by the user, and music to be listened to by the user is input from the input unit as an acoustic signal, and adjusting means Accordingly, the frequency characteristic of the acoustic signal and adjusts the frequency characteristics suitable for hearing characteristics of the user based on the output result from the hearing test means for performing the hearing test step adjustment scan In the adjusting step, a relational expression between the sound pressure coefficient and the frequency band is generated for each of the examined frequency bands, and a perceived sound pressure level tendency is determined based on the plurality of the relational expressions. The sound pressure level in the frequency band of the acoustic signal that is difficult for the user to hear from the estimation result is amplified by the adjusting means.

The acoustic adjustment method according to claim 9 of the present invention, prior Symbol hearing test step, until there is a response from the user to the test sound, the user while increasing the sound pressure level of the test sound for each frequency band a test sound output step of presenting the test sound for, and a specifying step of specifying the perceived sound pressure level by Ri for each of the frequency bands in response from the user, the adjusting step, the band separation unit The sound signal from the input unit is separated into a plurality of frequency bands, and the sound pressure level of the frequency band that is difficult for the user to hear for each of the frequency bands separated by the band separation unit by the adjustment unit, It is characterized by increasing or decreasing based on the estimation result .

In the acoustic adjustment method according to claim 10 of the present invention, in the auditory test step, the frequency band other than the frequency band in which the perceived sound pressure level is specified based on a relational expression between the sound pressure coefficient and the frequency band. the user-specific the perceived sound perceived sound pressure curve showing the pressure level trends calculated to the entire frequency band of the perceived sound pressure level trend, a generation step of generating as the speculative result, provided after the specific steps in, In the adjusting step, the sound pressure level is increased or decreased for each frequency band based on the perceived sound pressure curve.

  The acoustic method according to claim 11 of the present invention is characterized in that the perceived sound pressure curve is represented by an nth order polynomial relating to frequency, and a sound pressure adjustment level at each frequency is generated based on the nth order polynomial.

  The acoustic adjustment method according to claim 12 of the present invention is characterized in that the auditory test step generates and stores a plurality of the perceived sound pressure curves in advance.

  In the acoustic method according to claim 13 of the present invention, in the auditory test step, the perceived sound pressure curves of a plurality of users are generated and stored in advance, and the user can store the plurality of stored sound signals when reproducing an acoustic signal. The perceptual sound pressure curve suitable for the user is selected from the perceived sound pressure curves, and the sound pressure level is adjusted.

  Further, in the acoustic method according to claim 14 of the present invention, in the auditory test step, a minute sound is generated by a minute sound generating means, and when the user perceives the minute sound, the user is confirmed via a confirmation signal input means. The confirmation signal is inputted to specify the perceived sound pressure level.

  According to the acoustic device of claim 1 and the acoustic adjustment method of claim 8 of the present invention, it is easily determined where a specific frequency band that is difficult for the user to hear is obtained by an auditory test, and the sound that is difficult for the user to hear. By adjusting the frequency characteristics of the signal, the music can be adjusted to a sound pressure level that is easy for the user to hear in all frequency bands, and can thus be reproduced with good sound quality according to the auditory characteristics of the user.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(1) Overall Configuration of Audio Device In FIG. 1, reference numeral 1 denotes an audio device with an auditory characteristic adaptation function, and the audio device 1 as an acoustic device is connected to an acoustic test unit 2b as an auditory test means in an acoustic processing unit 2a. The sound processing unit 2a can automatically adjust the sound pressure level for each frequency band based on the result of the user's auditory test in the auditory test unit 2b, and can reproduce music with sound quality suitable for each user. It is made like that.

  In practice, the audio apparatus 1 reproduces various recording media such as CDs and DVDs by the input unit 3, and sequentially transmits a plurality of discrete data arranged in the time direction to the acoustic processing unit 2a. Incidentally, the discrete data is discrete data obtained by, for example, sampling a continuous signal that changes smoothly at regular time intervals and quantizing the sampling data obtained as a result.

  The acoustic processing unit 2a is set for each frequency band, a band separation unit 4 that separates discrete data into a plurality of frequency bands, a sound pressure adjustment unit 5 that adjusts a sound pressure level for each of the plurality of frequency bands. By combining the interpolation processing unit 6 that individually executes interpolation processing for each frequency band using a predetermined sampling function (described later) and the interpolation processing signal generated for each frequency band, It comprises a band synthesizing unit 7 that generates an analog signal. Then, the audio device 1 emits sound at the output unit 8 based on the analog signal from the band synthesizing unit 7.

  In addition to this configuration, the sound pressure adjusting unit 5 is connected to the auditory inspection unit 2b, and the sound pressure coefficient data for each band for individually increasing the sound pressure level for each frequency band is stored in the auditory inspection unit 2b. Can be sent from. Here, in the auditory test unit 2b, a confirmation signal input unit 10, a detection sound output unit 11, and a ratio calculation unit 12 are connected to a control unit 9 that comprehensively controls the operation of the entire auditory test unit 2b. The ratio calculation unit 12 is connected to a band-specific sound pressure coefficient calculation unit 13.

  The controller 9 gradually increases the sound pressure level of the inspection sound from the sound pressure level that the user can never hear for each of a plurality of frequencies, and the user can hear the sound for the first time. The sound pressure level can be determined by a listening response from the user, and the sound pressure level at the time of the listening response can be specified as the perceived sound pressure level of the user.

  Here, the listening response from the user is performed using the confirmation signal input unit 10. That is, the user releases the switch of the confirmation signal input unit 10 when the inspection sound cannot be heard, and presses the switch of the confirmation signal input unit 10 when the sound is heard. The control unit 9 receives a confirmation signal from the confirmation signal input unit 10 when the switch of the confirmation signal input unit 10 is pressed.

  Therefore, the control unit 9 as the specifying unit gradually increases the sound pressure level of the detection sound for each frequency, and the user generates the detection sound based on the timing when the confirmation signal is received from the confirmation signal input unit 10. The sound pressure level that can be heard can be specified as the perceived sound pressure level of the frequency. The controller 9 sends the perceived sound pressure level obtained for each frequency to the ratio calculator 12 as perceived sound pressure level data.

  Incidentally, in the case of this embodiment, the case where the perceived sound pressure level is specified by the user's own switch operation using the confirmation signal input unit 10 of the switch structure has been described. For example, the perceived sound pressure level is determined using various other confirmation signal input units, such as specifying the perceived sound pressure level for each user by a confirmation signal input unit that detects biological reactions such as the state of the eardrum and brain waves. May be specified.

  Here, in the auditory inspection unit 2b, a standard sound pressure curve indicating a statistical sound pressure level amplification tendency indicating how much a general user cannot hear sound and how much the sound pressure level is amplified is shown. It is created in advance based on a plurality of users' auditory examinations and stored in a memory (not shown).

  In the case of this embodiment, as shown in FIG. 2, the standard sound pressure curve C1 shows a minimum value in the vicinity of 4 kHz as the sound pressure level gradually decreases, for example, in a frequency band from 0 kHz to 4 kHz. The sound pressure level gradually increases in the frequency band up to 16 kHz, and the sound pressure level rapidly increases in the frequency band from 16 kHz to 40 kHz.

  That is, the standard sound pressure curve C1 indicates that the frequency at which a general user can easily hear the sound is around 4 kHz, and the sound pressure level is not increased at all around 4 kHz. Further, it can be seen from the standard sound pressure curve C1 that a general user becomes difficult to hear sound from the vicinity of 4 kHz to the low frequency band, and the sound pressure level is gradually increased. Further, it can be seen from this standard sound pressure curve C1 that a general user becomes difficult to hear the sound as it goes from around 4 kHz to a high frequency band, and the sound pressure level is gradually increased.

  When the ratio calculation unit 12 receives the perceived sound pressure level data from the control unit 9 for each frequency, the ratio calculation unit 12 specifies the standard sound pressure level at the same frequency as the perceived sound pressure level from the standard sound pressure curve C1, and determines the perceived sound pressure level. The sound pressure coefficient in each frequency band is calculated based on the specified standard sound pressure level. Specifically, as shown in FIG. 2, when the perceived sound pressure level at a predetermined frequency f1 is A1, and the standard sound pressure level at the same frequency f1 is A0, the sound pressure coefficient H (f1) is H ( f1) = A1 / A0. When the ratio calculation unit 12 calculates the sound pressure coefficient H (f), the ratio calculation unit 12 sends the sound pressure coefficient H (f) to the band-specific sound pressure coefficient calculation unit 13 as sound pressure coefficient data.

  In addition, the ratio calculation unit 12 is adjacent to the predetermined frequency f1 and also at the next frequency f2 after the auditory test, the perceived sound pressure level B1 at the frequency f2 and the standard sound pressure level at the same frequency f2. Sound pressure coefficient H (f2) = B1 / B0 is obtained from B0, and this is sent as sound pressure coefficient data to the sound pressure coefficient calculation unit 13 for each band.

  The sound pressure coefficient calculation unit 13 for each band is based on the sound pressure coefficient data received from the ratio calculation unit 12 and is an expression showing the relationship between the sound pressure coefficient H (f) and the frequency f, H (f) = a · a and b are calculated using f + b.

Specifically, the band-specific sound pressure coefficient calculation unit 13 substitutes the frequency f1 and the sound pressure coefficient H (f1) into the above equation, so that H (f1) = a · f1 + b. Further, the sound pressure coefficient calculation unit 13 for each band substitutes the frequency f2 and the sound pressure coefficient H (f2) into the above equation, so that H (f2) = a · f2 + b. Then, the sound pressure coefficient calculation unit 13 for each band calculates the values of a and b (for example, the determination of a) from the equation of H (f1) = a · f1 + b and the equation of H (f2) = a · f2 + b. The sound pressure coefficient line connecting the frequency f1 and the frequency f2, H (f) = a1 · f + b1, can be generated. In the above description, the relationship H (f) = a · f + b of the linear expression of the frequency f is shown. However, in order to perform higher performance adjustment, an n-order polynomial expression of the frequency f, for example, H (f) = a Approximation with a quadratic expression such as f ² + b · f + c does not depart from the scope of the present invention. In the case of a quadratic expression, coefficients a, b, and c can be determined from sound pressures at three frequencies.

  Next, the sound pressure coefficient calculation unit 13 for each band obtains a sound pressure coefficient H (f3) at a predetermined frequency f3 between the frequency f1 and the frequency f2 from the following equation, H (f3) = a1 · f3 + b1. The perceived sound pressure level at the frequency f3 is obtained by multiplying the standard sound pressure level at the frequency f3 by the sound pressure coefficient H (f3). Thus, the per-band sound pressure coefficient calculation unit 13 calculates the perceived sound pressure level at each frequency for which the perceived sound pressure level is not inspected based on the sound pressure coefficient line, the frequency, and the standard sound pressure level at that time. Have been made to guess. The band-specific sound pressure coefficient calculation unit 13 generates a perceptual sound pressure curve C2 in which the perceived sound pressure level tendency of all frequency bands from the low sound range to the high sound range is estimated, and uses this as perceptual sound pressure data as the sound processing unit. 2a is sent to the sound pressure adjusting unit 5.

  Incidentally, in the case of this embodiment, for example, when a hearing test was performed on a certain user, a perceived sound pressure curve C2 showing a tendency of perceived sound pressure level as shown in FIG. 2 was generated. In this perceived sound pressure curve C2, the perceived sound pressure level is higher than the standard sound pressure level at 0 kHz, and the sound pressure level rapidly decreases in the frequency band from 0 kHz to 4 kHz as compared with the standard sound pressure curve C1. In the frequency band from 4 kHz to 16 kHz, the sound pressure level suddenly increases as compared to the standard sound pressure curve C1.

  From this, it can be seen that the user who performed the auditory examination increased the sound pressure level as compared to the general user as the frequency range of the low and high sounds ranged. It shows that it is hard to hear a sound than a general user according to going to a frequency band. Then, the sound processing unit 2a performs sound pressure for each frequency according to the frequency range of the low sound range and the high sound range based on the perceptual sound pressure curve C2 generated based on the result of the auditory test received from the auditory test unit 2b. The level is amplified individually.

  As shown in FIG. 3, the sound pressure adjusting unit 5 is provided with a plurality of amplifiers 5a, 5b, 5c... Corresponding to each frequency band separated by the band separating unit 4, and each amplifier 5a, 5b. , 5c... Are provided with a plurality of amplifier circuits corresponding to the detected sound frequency and other predetermined frequencies. For example, when the amplifier 5a receives the perceived sound pressure data from the band-specific sound pressure coefficient calculation unit 13, the perceived sound pressure level at the frequency corresponding to each amplifier circuit is determined from the perceived sound pressure curve C2 based on the perceived sound pressure data. In particular, the sound pressure level of the band-specific signal can be amplified based on the perceived sound pressure level for each amplifier circuit. In this way, each of the amplifiers 5a, 5b, 5c... Can amplify the sound pressure level of the band-specific signal based on the perceived sound pressure level for each predetermined frequency in each frequency band.

  Incidentally, in the case of this embodiment, a test sound having a predetermined frequency is output, and the sound pressure level of the corresponding frequency portion is changed by the amplifiers 5a, 5b, 5c. However, the present invention is not limited to this, and a detection sound having a frequency band from a predetermined lower limit frequency to a predetermined upper limit frequency is output, and each amplifier 5a, 5b, 5c is output. ..., the sound pressure level of the corresponding frequency band portion may be amplified based on the perceived sound pressure level in the frequency band.

  When each amplifier 5a, 5b, 5c,... Amplifies each band signal as an acoustic signal to a predetermined sound pressure level based on the perceived sound pressure data and generates each band adjustment signal, each of these bands Another adjustment signal is sent to the interpolation processing unit 6. In this way, the sound pressure adjustment unit 5 increases the sound pressure level only for frequencies that are difficult for the user to hear according to the user's auditory characteristics obtained from the result of the auditory test in the auditory test unit 2b. Can be adjusted to a sound pressure level that can be easily heard by the user in all frequency bands.

  Incidentally, in this audio apparatus 1, in addition to being able to adjust the sound pressure level for each frequency in the sound pressure adjusting unit 5 as described above, the interpolation processing unit 6 can also adjust the sound pressure level. . The adjustment of the sound pressure level in the interpolation processing unit 6 may be further executed after the sound pressure level is adjusted by the sound pressure adjusting unit 5, or only the interpolation processing unit 6 or the sound pressure adjustment. The sound pressure level may be adjusted only by the unit 5.

  Hereinafter, the interpolation processing executed in the interpolation processing unit 6 will be described. Here, the interpolation processing unit 6 is provided with a plurality of band-specific interpolation units 6a, 6b, 6c,... Corresponding to each frequency band separated by the band separation unit 4, and the control unit 9 of the auditory examination unit 2b. Can be set for each of the interpolators 6a, 6b, 6c... For each of the bands. Thus, the interband interpolation units 6a, 6b, 6c,... Individually perform predetermined interpolation processing for each adjustment signal for each band in each frequency band according to the sampling function set by the control unit 9 according to the user's auditory characteristics. This is executed to interpolate between the band-specific data constituting each band-specific adjustment signal to increase the sampling frequency in a pseudo manner, and the resultant interpolated signal is sent to the band synthesizing unit 7.

  For example, as shown in FIG. 2, when an auditory result in which the sound pressure level is increased in the high frequency range is obtained, the sound pressure level is higher than a predetermined threshold value in a specific high frequency range, for example. When increased, it can be determined that it is difficult for the user to hear the high frequency range, and a sampling function that amplifies the sound pressure level in the high frequency range can be automatically selected. Thereby, the acoustic processing unit 2a can adjust the interpolation value for interpolating between the band-specific data so that the high-frequency range is amplified for each band-specific adjustment signal, and can increase or decrease the sound pressure level of each frequency band. Has been made.

  The band synthesizing unit 7 generates one analog signal composed of the entire frequency band by synthesizing a plurality of interpolation processing signals generated by the interpolating units 6a, 6b, 6c, etc. for each band, and outputs this to the output unit 8. Send it out. Incidentally, in this embodiment, the generation of signals at high frequency discrete intervals and the generation of analog signals are referred to as “analog signal generation” as the same processing. In this way, the audio apparatus 1 can generate an interpolated signal adjusted for each frequency band, and thus the sound pressure level of each frequency band of the analog signal is automatically finely adjusted for each user based on an auditory test. Thus, the music having the sound quality desired by the user can be reproduced from the output unit 8.

(2) Interpolation Processing in the Interpolation Unit by Band Next, an outline of the interpolation processing executed by the interpolation units by band 6a, 6b, 6c. Note that the case where the value of the function has a finite value other than 0 in a local region and becomes 0 in other regions will be referred to as a “finite platform”. The sampling function s _N (t) used in the interband interpolation units 6a, 6b, 6c... Is composed of a basic sampling function f (t) and a control sampling function c ₀ (t). Here, the sampling position of the discrete data is assumed to be t, and, for example, a sampling consisting of a basic sampling function f (t) and a control sampling function c ₀ (t) between the sampling positions [−2, 2] of the discrete data. The function s ₂ (t) is given by

によって表され、一般的な制御標本化関数をｃ_k（ｔ）とし、ｃ_k（ｔ）＝ｃ_r（ｔ−ｋ）＋ｃ_r（−ｔ−ｋ）と置いたときは、当該離散データの標本位置［−Ｎ，Ｎ］間で標本化関数ｓ_N（ｔ）は次式

When a general control sampling function is expressed as c _k (t) and c _k (t) = c _r (t−k) + c _r (−t−k), the discrete data The sampling function s _N (t) between sample positions [−N, N] is

によって表される。なお、α_kは後述する可変パラメータを示し、ユーザによって設定可能な任意の数値を示すもので、α₁＝α₂＝α₃…のようにｋによって可変しないものである。因みに、Ｎ＝２のときの標本化関数ｓ₂（ｔ）については、説明の便宜上、単に標本化関数ｓ_N（ｔ）として以下説明する。

Represented by Α _k represents a variable parameter to be described later, and represents an arbitrary numerical value that can be set by the user, and does not vary with k as α ₁ = α ₂ = α ₃ . Incidentally, the sampling function s ₂ (t) when N = 2 will be described below simply as the sampling function s _N (t) for convenience of explanation.

Since the sampling function s _N (t) can calculate an interpolation value reflecting the value of the variable parameter α, the interpolation processing signal can be adjusted for each frequency band by changing the value of the variable parameter α. Has been made. The basic sampling function f (t) and the control sampling function c ₀ (t) show waveforms as shown in FIG. 4, and the waveform shown by the control sampling function c ₀ (t) according to the value of the variable parameter α. The amplitude of can be increased and decreased.

  The basic sampling function f (t) is a function of a finite stage focusing on differentiability. For example, the basic sampling function f (t) can be differentiated only once in the entire region, and the sample position t along the horizontal axis is −1 to +1 (ie, , [−1, 1]) has a finite value other than 0, and the other intervals are functions that are represented as 0 by identity. Specifically, the basic sampling function f (t) is a quadratic expression in a typical function form, shows a convex waveform that can be differentiated only once in the entire range, and is 1 only at a sample position of t = 0. And converges to 0 toward t = ± 1 and reaches 0 as it is until the sample position of t = ± 2.

  The basic sampling function f (t) may be an n-order impulse response function of a finite number, and may be an n-th order piecewise polynomial function that is continuous at the point where sample points are divided. Specifically, in the case of a quadratic piecewise polynomial function, such a basic sampling function f (t)

によって表される。そして、この基本標本化関数ｆ（ｔ）を用いて帯域別調整信号を構成する各帯域別データに基づく重ね合わせを行うことにより、帯域別調整信号の帯域別データ間の値を１回だけ微分可能な関数を用いて仮補間することができる。

Represented by Then, by using the basic sampling function f (t) to perform superposition based on each band-specific data constituting the band-specific adjustment signal, the value between the band-specific data of the band-specific adjustment signal is differentiated only once. Temporary interpolation can be performed using possible functions.

On the other hand, the control sampling function c ₀ (t) is a function of a finite stage focusing on differentiability, and can be differentiated only once in the entire region, for example, and the sample position t along the horizontal axis is from −2. It is a function that has a finite value other than 0 when it is in +2 (that is, the interval [−2, 2]), and is uniformly expressed as 0 in other intervals. Further, the control sampling function c ₀ (t) shows a waveform that can be differentiated only once in the entire range, and has a feature that it becomes 0 at each sample position of t = 0, ± 1, ± 2.

The control sampling function c ₀ (t) may be an nth-order impulse response function of a finite number, and may be an n-th order piecewise polynomial function that is continuous at points obtained by dividing between sample points. Here, the control sampling function c ₀ (t) is represented by the control sampling function c ₀ (t) = c _r (t) + c _r (−t) as described above, and this _cr (t) is Specifically,

によって表される。そして、この制御標本化関数ｃ₀（ｔ）を用いて帯域別調整信号の各帯域別データに基づく重ね合わせを行うことにより、帯域別調整信号の帯域別データ間の値を１回だけ微分可能な関数を用いて仮補間することができる。

Represented by Then, by using the control sampling function c ₀ (t) to perform superposition based on the band-specific data of the band-specific adjustment signal, the value between the band-specific data of the band-specific adjustment signal can be differentiated only once. Can be interpolated using a simple function.

The sampling function s _N (t) is represented by a linear combination of the basic sampling function f (t) and the control sampling function c ₀ (t), and the actual interpolation operation is the basic sampling function f (t). A convolution operation between a temporary interpolation value (hereinafter referred to as a basic interpolation value) calculated by a convolution operation with discrete data (sample values), a control sampling function c ₀ (t), and discrete data (sample values) By linearly adding the provisional interpolation value calculated in step (hereinafter referred to as the control interpolation value), the value between the band-specific data of the band-specific adjustment signal is interpolated using a function that can be differentiated only once. be able to.

Incidentally, the linear combination of the basic sampling function f (t) and the control sampling function c ₀ (t) is a function that satisfies the following six conditions. First, S ₂ (0) = 1, S ₂ (± 1) = S ₂ (± 2) = 0. Secondly, it should be symmetric with respect to the even function, ie the y-axis. Thirdly, the sample position interval [−∞, −2], [2, ∞] should be zero on the identity. Fourthly, each section [n / 2, (n + 1) / 2] (−4 ≦ n ≦ 3) is at most a quadratic polynomial. Fifth, all sections should be C1 class, that is, differentiable continuously once. Sixth, in the sample position section [−1/2, 1/2],

となること。

To be.

Here, the control sampling function c ₀ (t) is arbitrary when, for example, it is determined from the perceived sound pressure curve C2 (FIG. 2) that the sound pressure level has increased beyond a predetermined threshold in the high sound frequency band. Can be automatically multiplied, or can be multiplied by an arbitrary numerical value α set by a user by a setting unit (not shown).

Thus, the control sampling function c ₀ (t) is set to the numerical value of the variable parameter α between the sample positions −2 and +2 while keeping 0 at the sample positions of t = 0, ± 1, ± 2. Accordingly, the amplitude of the waveform can be modified. As a result, the control sampling function c ₀ (t) can change the calculation result by the convolution operation with the discrete data (sample value). Thus, the variable parameter α can change the frequency characteristic of the interpolation processing signal calculated by the sampling function s _N (t) by changing the numerical value, and the high frequency component of each frequency band can be changed. The signal level can be adjusted.

Therefore, the audio apparatus 1 adjusts the interpolation processing signal by changing the variable parameter α multiplied by the control sampling function c ₀ (t) for each frequency band, and is generated for each frequency band. By synthesizing a plurality of interpolation processing signals to generate an analog signal, it is possible to generate an analog signal having a sound quality desired by the user whose high sound range is finely adjusted for each frequency band.

(3) Circuit configuration of interpolator for each band (3-1) Outline description of interpolation processing in interpolator for each band The three interpolators 6a, 6b, and 6c for each band are sampling functions s _N (t) used for the interpolation process. The variable parameter α is set individually and the adjustment signal for each band to be interpolated is different, but the other points have the same configuration. Description will be made by paying attention to one interpolator 6a for each band that interpolates the adjustment signal.

  As shown in FIG. 5, the band-by-band interpolation unit 6 a includes a data extraction unit 15 that sequentially extracts and holds a predetermined number (four in this case) of band-by-band data constituting the band-by-band adjustment signal, and a data extraction unit 15. And a function processing unit 14 for receiving a predetermined number of band-specific data extracted and held at a time and performing interpolation using these band-specific data, and a predetermined interval between the band-specific data sequentially input from the amplifier 5a. The data can be interpolated at the time interval.

The function processing unit 14 includes a basic term operation unit 16 for processing a convolution operation between the term of the basic sampling function f (t) and the band-specific data in the sampling function s _N (t), and a sampling function s _N ( t) of the control sampling function c ₀ (t) and the control term calculation unit 17 for processing the convolution calculation of the band-specific data, and coefficient multiplication for multiplying the calculation result of the control term calculation unit 17 by the variable parameter α. Unit 18 and an addition operation unit 19 that linearly adds the calculation result of the basic term calculation unit 16 and the calculation result of the coefficient multiplication unit 18.

  In the case of this embodiment, the data extraction unit 15 extracts the previous four band-specific data from the band-specific data that are sequentially input, and these four bands are then input until new band-specific data is next input. Separate data is held, and these four band-specific data are sent to the basic term calculation unit 16 and the control term calculation unit 17, respectively.

  The basic term calculation unit 16 stores a basic sampling function f (t) in a predetermined storage means (not shown), and when an interpolation position between band-specific data is designated, this interpolation position and band-specific calculation are performed. Based on the distance to the data, the value of the basic sampling function f (t) is calculated. The basic term calculation unit 16 can calculate the value of the basic sampling function f (t) for each of the four band-specific data transmitted from the data extraction unit 15. Further, the basic term calculation unit 16 multiplies the values of the band-specific data corresponding to the values of the four basic sampling functions f (t) obtained for the band-specific data, and then the four band-specific data. The convolution operation corresponding to is performed, and the calculation result of the convolution operation is sent to the addition operation unit 19.

At the same time, the control term calculation unit 17 stores the control sampling function c ₀ (t) in a predetermined storage means (not shown), and when an interpolation position is designated, this interpolation position and band-specific data The value of the control sampling function c ₀ (t) is calculated based on the distance between. The control term calculation unit 17 can calculate the value of the control sampling function c ₀ (t) for each of the four band-specific data transmitted from the data extraction unit 15. Further, the control term calculation unit 17 multiplies the values of the corresponding band-specific data for each value of the four control sampling functions c ₀ (t) obtained for the band-specific data, and then adds these. Thus, the convolution operation corresponding to the four band-specific data is performed, and the calculation result of the convolution operation is sent to the coefficient multiplier 18.

The coefficient multiplication unit 18 multiplies the calculation result of the convolution operation of the control sampling function c ₀ (t) received from the control term calculation unit 17 by the variable parameter α selected based on the user's auditory test, and the result The obtained variable parameter multiplication result is sent to the addition operation unit 19. The addition calculation unit 19 linearly adds the calculation result of the convolution calculation of the basic sampling function f (t) received from the basic term calculation unit 16 and the variable parameter multiplication result received from the coefficient multiplication unit 18 to obtain 4 An operation result corresponding to one band-specific data is obtained. A value obtained by this linear addition is an interpolation value at an interpolation position between two predetermined band-specific data. Incidentally, the value of this interpolation position is updated every predetermined period of time, specifically, every 1 / N period (= T / N) of the period T corresponding to the input interval of the band-specific data. The

(3-2) Specific example of obtaining an interpolation value based on four band-specific data Next, an interpolation value between two predetermined band-specific data is calculated based on four band-specific data arranged in time series. The interpolation processing to be performed will be described below with reference to FIG. 6 showing the positional relationship between the continuous four band-specific data and the point of interest that is the interpolation position. In FIG. 6, the values of the band-specific data d1, d2, d3, d4 sequentially input corresponding to the respective sample positions t1, t2, t3, t4 are represented by Y (t1), Y (t2), Y ( Assume that t3) and Y (t4) are set, and an interpolation value y corresponding to a predetermined position between the sample positions t2 and t3 (that is, the interpolation position (distance b from t2)) t0 is obtained.

Since the sampling function s _N (t) used in the present embodiment converges to 0 at the sample position of t = ± 2, the band-specific data d1, d2, d3, d4 up to t = ± 2 is taken into consideration. That's fine. Therefore, when obtaining the interpolation value y shown in FIG. 6, it is only necessary to consider the four band-specific data d1, d2, d3, d4 corresponding to t = t1, t2, t3, t4. The amount can be greatly reduced. In addition, data for each band (not shown) of t = ± 3 or more should be considered originally, but is not ignored in consideration of the amount of calculation and accuracy, but is considered theoretically. There is no need for censoring errors.

  As shown in FIG. 7, the data extraction unit 15 includes three shift circuits 20a, 20b, and 20c. When continuous band-specific data is input, the corresponding band is obtained for each shift circuit 20a, 20b, and 20c. The different data is shifted, for example, at a CD sampling period (44.1 kHz), and each of the shift circuits 20a, 20b, and 20c can extract and hold the previous band-specific data d1, d2, d3, and d4, respectively. That is, when four consecutive band-specific data d1, d2, d3, d4 are input, the data extraction unit 15 uses the latest band-specific data d4 as it is and the basic term calculation circuit 21a and the control term of the basic term calculation unit 16. Each is sent to the control term calculation circuit 22a of the calculation unit 17.

  Further, the data extraction unit 15 sends a band-specific data string composed of four consecutive band-specific data d1, d2, d3, d4 to the shift circuit 20a, and the shift circuit 20b shifts the band-specific data string to the latest. The previous band-specific data d3 is extracted from the band-specific data d4 and sent to the basic term calculation circuit 21b of the basic term calculation unit 16 and the control term calculation circuit 22b of the control term calculation unit 17, respectively.

  Further, the data extraction unit 15 sequentially transmits the band-specific data string to the remaining shift circuits 20b and 20c, and further shifts the band-specific data string by the shift circuit 20b, so that two data from the latest band-specific data d4 are obtained. The previous band-specific data d2 is sent to the basic term calculation circuit 21c and the control term calculation circuit 22c, respectively, and the band-specific data string is further shifted by the shift circuit 20c, so that the previous band-specific data d4 is changed by the previous three bands. The data d1 is sent to the basic term calculation circuit 21d and the control term calculation circuit 22d.

  Here, FIGS. 8 and 9 are diagrams showing an outline of the interpolation processing for the predetermined interpolation position t0 in the basic term calculation unit 16 and the control term calculation unit 17 of the present embodiment. As the contents of the interpolation processing, as described above, first, the calculation processing for calculating the basic interpolation value in the basic term calculation unit 16 (hereinafter simply referred to as basic interpolation value calculation processing), the control term calculation unit 17 Then, a calculation process for calculating a control interpolation value in the coefficient multiplication unit 18 (hereinafter simply referred to as a control interpolation value calculation process) is executed. Hereinafter, the basic interpolation value calculation process and the control interpolation value calculation process will be described with reference to FIGS. 8 and 9.

(3-2-1) Basic Interpolation Value Calculation Processing As shown in FIGS. 8A to 8D, the basic interpolation value calculation processing includes basic information for each sample position t1, t2, t3, and t4. The peak heights at t = 0 (center position) of the sampling function f (t) are matched, and the value of each basic sampling function f (t) at the interpolation position t0 at this time is obtained.

  Focusing on the band-specific data d1 at the sample position t1 shown in FIG. 8A, the distance between the interpolation position t0 and the sample position t1 is 1 + b. Therefore, the value of the basic sampling function at the interpolation position t0 when the center position of the basic sampling function f (t) is aligned with the sample position t1 is f (1 + b). Actually, in order to match the peak height of the center position of the basic sampling function f (t) so as to match the value Y (t1) of the band-specific data d1, the above-described f (1 + b) is multiplied by Y (t1). The obtained value f (1 + b) · Y (t1) is a desired value. Calculation of f (1 + b) is performed by the basic term calculation circuit 21a of the basic term calculation unit 16, and calculation for multiplying f (1 + b) by Y (t1) is performed by the basic term multiplication circuit 23a of the basic term calculation unit 16. (FIG. 7).

  Similarly, paying attention to the value Y (t2) of the band-specific data d2 at the sample position t2 shown in FIG. 8B, the distance between the interpolation position t0 and the sample position t2 is b. Therefore, the value of the basic sampling function at the interpolation position t0 when the center position of the basic sampling function f (t) is aligned with the sampling position t2 is f (b). Actually, in order to match the peak height of the center position of the basic sampling function f (t) so as to match the value Y (t2) of the band-specific data d2, the above-described f (b) is multiplied by Y (t2) times. The obtained value f (b) · Y (t2) is a desired value. The calculation of f (b) is performed by the basic term calculation circuit 21b of the basic term calculation unit 16, and the calculation of multiplying f (b) by Y (t2) is performed by the basic term multiplication circuit 23b of the basic term calculation unit 16. (FIG. 7).

  Focusing on the value Y (t3) of the band-specific data d3 at the sample position t3 shown in FIG. 8C, the distance between the interpolation position t0 and the sample position t3 is 1-b. Therefore, the value of the basic sampling function at the interpolation position t0 when the center position of the basic sampling function f (t) is aligned with the sampling position t3 is f (1-b). Actually, in order to match the peak height of the center position of the basic sampling function f (t) so as to coincide with the value Y (t3) of the band-specific data, the above-described f (1-b) is changed to Y (t3). The multiplied value f (1-b) · Y (t3) is the value to be obtained. The calculation of f (1-b) is performed by the basic term calculation circuit 21c of the basic term calculation unit 16, and the calculation of multiplying f (1-b) by Y (t3) is the basic term multiplication circuit of the basic term calculation unit 16. 23c (FIG. 7).

  Focusing on the value Y (t4) of the band-specific data d4 at the sample position t4 shown in FIG. 8D, the distance between the interpolation position t0 and the sample position t4 is 2-b. Therefore, the value of the basic sampling function at the interpolation position t0 when the center position of the basic sampling function f (t) is aligned with the sampling position t4 is f (2-b). Actually, in order to match the peak height of the center position of the basic sampling function f (2-b) so as to match the value Y (t4) of the band-specific data d4, the above-described f (2-b) is set to Y The value f (2-b) · Y (t4) multiplied by (t4) is the desired value. The calculation of f (2-b) is performed by the basic term calculation circuit 21d of the basic term calculation unit 16, and the calculation of multiplying f (2-b) by Y (t4) is the basic term multiplication circuit of the basic term calculation unit 16. 23d (FIG. 7).

  The basic term calculation unit 16 then obtains four values f (1 + b) · Y (t1), f (b) · Y (t2), and f (1−b) obtained corresponding to the point of interest at the interpolation position t0. ) · Y (t3) and f (2-b) · Y (t4) are convolved in the basic term convolution circuit 24 to calculate a basic interpolation value ya in a predetermined frequency band. Incidentally, in the case of this embodiment, the values f (1 + b) · Y (t1) and f (2-b) · Y (t4) obtained corresponding to the point of interest at the interpolation position t0 are shown in FIG. ) And 0 as shown in (D), the basic interpolation value ya is {f (b) · Y (t2)} + {f (1−b) · Y (t3)}.

(3-2-2) Control Interpolation Value Calculation Processing On the other hand, as the contents of the control interpolation value calculation processing, as shown in FIGS. 9A to 9D, for each sample position t1, t2, t3, t4 , to match the t = 0 (center position) of the control sampling function c ₀ (t), the band-by-band data d1 corresponding to each control sampling function _{c 0 (t), d2,} d3, d4 of the value Y ( t1), Y (t2), Y (t3), and Y (t4) are multiplied, and the value of each control sampling function c ₀ (t) at the interpolation position t0 at this time is obtained.

Focusing on the value Y (t1) of the band-specific data d1 at the sample position t1 shown in FIG. 9A, the distance between the interpolation position t0 and the sample position t1 is 1 + b. Therefore, the value of the control sampling function at the interpolation position t0 when the center position of the control sampling function c ₀ (t) is aligned with the sample position t1 is c ₀ (1 + b). Actually, in order to match the waveform height of the control sampling function c ₀ (t) in correspondence with the value Y (t 1) of the band-specific data d 1, a value obtained by multiplying the above c ₀ (1 + b) by Y (t 1). c ₀ (1 + b) · Y (t1) is a desired value. The calculation of c ₀ (1 + b) is performed by the control term calculation circuit 22a of the control term calculation unit 17, and the calculation of multiplying c ₀ (1 + b) by Y (t1) is performed by the control term multiplication circuit 25a of the control term calculation unit 17. Performed (FIG. 7).

Similarly, focusing on the value Y (t2) of the band-specific data d2 at the sample position t2 shown in FIG. 9B, the distance between the interpolation position t0 and the sample position t2 is b. Therefore, the value of the control sampling function at the interpolation position t0 when the center position of the control sampling function c ₀ (t) is aligned with the sample position t2 is c ₀ (b). Actually, in order to match the waveform height of the control sampling function c ₀ (t) in correspondence with the value Y (t 2) of the band-specific data d 2, a value obtained by multiplying the above c ₀ (b) by Y (t 2). c ₀ (b) · Y (t2) is a desired value. The calculation of c ₀ (b) is performed by the control term calculation circuit 22b of the control term calculation unit 17, and the calculation of multiplying c ₀ (b) by Y (t2) is performed by the control term multiplication circuit 25b of the control term calculation unit 17. Performed (FIG. 7).

Focusing on the value Y (t3) of the band-specific data d3 at the sample position t3 shown in FIG. 9C, the distance between the interpolation position t0 and the sample position t3 is 1-b. Therefore, the value of the control sampling function at the interpolation position t0 when the center position of the control sampling function c ₀ (t) is aligned with the sampling position t3 is c ₀ (1-b). Actually, in order to match the waveform height of the control sampling function c ₀ (t) in correspondence with the value Y (t 3) of the band-specific data d ₃ , the above c ₀ (1-b) is multiplied by Y (t 3). The value c ₀ (1-b) · Y (t3) is the value to be obtained. The calculation of c ₀ (1-b) is performed by the control term calculation circuit 22c of the control term calculation unit 17, and the calculation of multiplying c ₀ (1-b) by Y (t3) is the control term of the control term calculation unit 17. This is performed by the multiplication circuit 25c (FIG. 7).

Focusing on the value Y (t4) of the band-specific data d4 at the sample position t4 shown in FIG. 9D, the distance between the interpolation position t0 and the sample position t4 is 2-b. Therefore, the value of the control sampling function at the interpolation position t0 when the center position of the control sampling function c ₀ (t) is aligned with the sampling position t4 is c ₀ (2-b). Actually, in order to match the waveform height of the control sampling function c ₀ (2-b) in correspondence with the value Y (t4) of the band-specific data d4, the above-described c ₀ (2-b) is changed to Y (t4). ) The multiplied value c ₀ (2-b) · Y (t4) is the desired value. The calculation of c ₀ (2-b) is performed by the control term calculation circuit 22d of the control term calculation unit 17, and the calculation of multiplying c ₀ (2-b) by Y (t4) is the control term of the control term calculation unit 17. This is performed by the multiplication circuit 25d (FIG. 7).

Then, four values c ₀ (1 + b) · Y (t1), c ₀ (b) · Y (t2), c ₀ (1−b) · Y () obtained corresponding to the point of interest at the interpolation position t0. t3), c ₀ (2-b) · Y (t4) are subjected to a convolution operation by the control term convolution circuit 26 of the control term operation unit 17, and then multiplied by the variable parameter α in the coefficient multiplication unit 18, whereby a predetermined parameter is obtained. A control interpolation value yb in the frequency band is calculated.

(3-2-3) Interpolation Value Calculation Processing The addition calculation unit 19 is calculated by the basic interpolation value ya corresponding to the target point calculated by the basic term calculation unit 16, the control term calculation unit 17, and the coefficient multiplication unit 18. The interpolation value y at the interpolation position t0 in a predetermined frequency band can be output by linearly adding the control interpolation value yb corresponding to the target point. In this manner, interpolation values are similarly calculated for all other interpolation positions between the band-specific data d2 and d3, and the band-based interpolation units 6b and 6c are also provided for each frequency band of the middle sound range and the high sound range. A similar interpolation processing technique can be executed using the set sampling function.

(3-3) Interpolation Processing Result when Variable Parameter Values are Changed In addition to such a configuration, the acoustic processing unit 2a can change the coefficient multiplying unit 18 based on the threshold value of the perceptual sound pressure curve C2 or user settings. The value of the sampling function s _N (t) is changed for each interpolator 6a, 6b, 6c for each band by appropriately changing the numerical value of the parameter α for each interpolator 6a, 6b, 6c for each band, The interpolation value y can be adjusted for each frequency band. As a result, the analog signal generated in the band synthesizing unit 7 can be adjusted in frequency characteristics by changing the numerical value of the variable parameter α for each frequency band. Here, with respect to how the sampling function s _N (t) changes when the variable parameter α is changed, the waveform shown by the basic sampling function f (t) shown in FIG. The following description will be focused on a waveform obtained by combining the waveform indicated by the function c ₀ (t).

As shown in FIG. 10, the waveform of the sampling function s _N (t) obtained by synthesizing the waveform indicated by the basic sampling function f (t) and the waveform indicated by the control sampling function c ₀ (t) is a variable parameter. It varies greatly depending on the numerical value of α. In this embodiment, when the variable parameter α is sequentially changed to −1.5, −0.25, and 1.5, the region of −2 ≦ t ≦ −1 and the region of 1 ≦ t ≦ 2 Then, it was confirmed that the amplitude of the wavelength of the sampling function s _N (t) gradually increased and the waveform polarity was inverted. On the other hand, in the region of −1 ≦ t ≦ 0 and the region of 0 ≦ t ≦ 1, it was confirmed that the wavelength amplitude of the sampling function s _N (t) gradually decreased and the polarity of the waveform was inverted.

By the way, the discrete data obtained by playing the violin song “Zigeunerweisen” recorded on CD as a test song for 23 seconds is not separated into the low, mid and high frequency bands. The interpolation processing was performed as is. At this time, the variable parameter α is set to −0.25, −1.5, and 1.5, respectively, and the frequency characteristics of the analog signals interpolated with each sampling function s _N (t) are compared. The results as shown in Fig. 1 were obtained.

As shown in FIG. 11, in the interpolation process using each sampling function s _N (t) in which the numerical value of the variable parameter α is changed, a high frequency range of 20 kHz or higher that is difficult to reproduce by using the conventional Shannon sampling function is used. It was confirmed that the signal can be reproduced regardless of the value of the variable parameter α. The waveform having such characteristics is the same as the signal on the high frequency side even when the adjustment signal for each band obtained by separating the discrete data into various frequency bands such as the low frequency range, the middle frequency range, and the high frequency range is interpolated. As compared with the case where the conventional Shannon sampling function is used, the high frequency range component within the low frequency range, the mid frequency range and the high frequency range are reproduced. obtain.

  Further, when the variable parameter α is set to 1.5, −1.5, or −0.25, the waveforms of the respective signal levels are different from each other. A waveform having such characteristics is similarly formed even when interpolation processing is performed on each band-specific adjustment signal obtained by separating discrete data into various frequency bands such as a low sound range, a mid sound range, and a high sound range. Therefore, by appropriately changing the numerical value of the variable parameter α for each frequency band, it is possible to individually adjust the signal level within each frequency band such as a low sound range, a middle sound range, and a high sound range.

As described above, the acoustic processing unit 2a can adjust the fine signal level for each frequency band by changing the variable parameter α of the sampling function s _N (t) for each frequency band. It is possible to make the user easily perform finer adjustment of characteristics. Thus, in the audio apparatus 1, each interpolation processing signal is individually adjusted by changing the variable parameter α for each frequency band, and an analog signal is generated by synthesizing the plurality of adjusted interpolation processing signals. Thus, it is possible to generate an analog signal whose high sound range is finely adjusted for each frequency band.

(4) Operation and effect In the above configuration, the auditory detection unit 2b gradually increases the sound pressure level for each detection sound of each frequency, and based on the timing when the confirmation signal is received from the confirmation signal input unit 10. The sound pressure level at which the user can hear the detected sound is specified for each frequency as the perceived sound pressure level. As a result, the acoustic processing unit 2a determines where the specific frequency band that is difficult for the user to hear from the difference in the sound pressure level between the perceived sound pressure level and the standard sound pressure level, and individually for each frequency band. The amplifiers 5a, 5b, 5c,... Provided can amplify the sound pressure level only in a frequency band that is difficult for the user to hear, thereby adjusting the entire frequency band to a sound pressure level that is easy for the user to hear. Music or the like can be reproduced with good sound quality according to the user's auditory characteristics.

  In the auditory detection unit 2b, a standard sound pressure curve C1 indicating a statistical sound pressure level amplification tendency is stored in advance, and for each frequency based on the standard sound pressure curve C1 and the perceived sound pressure level. A sound pressure coefficient is calculated, and a perceived sound pressure level at a frequency other than the frequency at which the perceived sound pressure level is directly specified by an auditory test is estimated from the relationship between the sound pressure coefficient, the frequency, and the standard sound pressure level. Therefore, the acoustic processing unit 2a can estimate a frequency that is difficult for the user to hear even if the perceived sound pressure level is not inspected, and finely amplify the sound pressure level accordingly. Music and the like can be reproduced with good sound quality according to the auditory characteristics.

  Further, in the auditory detection unit 2b, when the user perceives the minute detection sound (micro sound) generated from the detection sound output unit 11 as the minute sound generation means, the user reacts and makes his own intention. By making the confirmation signal input unit 10 switch-operated, the minimum sound pressure level felt by the user himself / herself can be specified accurately and reliably, thus music with good sound quality according to the user's auditory characteristics, etc. Can be played.

(5) Other Embodiments The present invention is not limited to the present embodiment, and various modifications can be made within the scope of the gist of the present invention. For example, a plurality of perceived sound pressure curves C2 are generated in advance according to various categories related to users such as age, gender, or individual family members, and the plurality of perceived sound pressure curves C2 are stored in the auditory examination unit. It may be. In this case, as shown in FIG. 12, the audio apparatus 100 stores a plurality of perceptual sound pressure curves C2 generated in advance by the band-specific sound pressure coefficient calculation unit 13 and the storage unit 102. The auditory examination unit 101 includes a selection unit 103 including a selection button for selecting a plurality of perceptual sound pressure curves C2.

  The selection unit 102 generates a predetermined selection signal in response to a selection operation by the user and reproduces it to the storage unit 101 when reproducing an acoustic signal for reproducing music or the like. As a result, the storage unit 102 selects a predetermined perceptual sound pressure curve C2 corresponding to the selection signal from a plurality of perceived sound pressure curves C2 stored in advance, and sends this to the sound pressure adjustment unit 5. Thus, the sound pressure adjusting unit 5 can execute the same process as described above using the perceived sound pressure curve C2. According to the above configuration, the audio device 1 can reproduce music or the like with good sound quality according to the user's auditory characteristics by only allowing the user to perform a selection operation when reproducing the sound signal. Each time, it is possible to save the user from having to perform an auditory examination.

  In the embodiment described above, the perceived sound pressure curve C2 is generated, the perceived sound pressure level is specified from the perceived sound pressure curve C2, and the frequency-dependent adjustment signal for the corresponding frequency based on the perceived sound pressure level. However, the present invention is not limited to this, and only the perceived sound pressure level specified by the auditory test is directly used without generating the perceptual sound pressure curve C2. Another adjustment signal may be amplified.

  In the above-described embodiment, the case where the frequency that is difficult for the user to hear is amplified based on the perceived sound pressure level and adjusted to the sound pressure level that is easy for the user to hear in all frequency bands has been described. The invention is not limited to this, and the frequency at which the user can easily hear may be attenuated based on the perceived sound pressure level, and adjusted to the sound pressure level at which the user can easily hear in all frequency bands. The sound pressure level may be increased or decreased based on the above, so that the user can easily hear in all frequency bands.

Furthermore, in the above-described embodiment, the case where the interpolation process using the sampling function s _N (t) is applied as the interpolation process is described, but the present invention is not limited to this, and the sampling function is used. In addition to the interpolation process, various other interpolation processes may be applied.

Also, here, a sampling function s _N (t) composed of a basic sampling function f (t) and a control sampling function c ₀ (t) is used, and the control sampling function c ₀ (t) is multiplied. Although the case where the interpolation processing signal is adjusted by changing the numerical value of the variable parameter α has been described, the present invention is not limited to this, and the Shannon sampling function is selected in addition to the sampling function s _N (t). Alternatively, the interpolation processing signal may be adjusted by simply selecting various sampling functions set in advance.

For example, although the sampling function s _N (t) is a function of a finite stage that can be differentiated only once in the entire region, the number of differentiable times may be set to 2 or more. Furthermore, in the above-described embodiment, the case where an analog signal is generated as a synthesized signal by performing an interpolation process using the sampling function s _N (t) is described, but the present invention is not limited to this. Alternatively, an oversampled composite signal may be generated by performing an interpolation process using the sampling function s _N (t), and then an analog signal may be generated by an analog-to-digital converter.

Furthermore, in the above-described embodiment, the case where the sampling function s _N (t) converges to 0 at t = ± 2 is described, but this is not limiting, and the sampling function s _N (t) becomes 0 at t = ± 3 or more. You may make it converge. For example, when t = ± 3 and converge to 0, the data extraction unit 15 extracts the previous six discrete data, and the function processing unit 14 performs sampling function s on these six discrete data. The value of _N (t) can be calculated.

Furthermore, in the above-described embodiment, the basic sampling function f (t) is stored in the basic term calculation unit 16, and separately, the control sampling function c ₀ (t) is stored in the control term calculation unit 17. The basic interpolation value ya and the control interpolation value yb are calculated by performing a convolution operation on the band-specific data d1, d2, d3, d4 for each basic sampling function f (t) and control sampling function c ₀ (t). In the above description, the basic interpolation value ya and the control interpolation value yb are linearly added to calculate the interpolation value y. However, the present invention is not limited to this, and the basic sampling function f (t) and the control are calculated. sampling function c ₀ (t) is pre-linear addition is stored as a single sampling function s _N (t) by using the sampling changed the variable parameter α function s _N (t), the band-by-band data Interpolation operation is performed on d1, d2, d3, and d4 to directly calculate the interpolation value y. You may make it do.

It is a block diagram which shows the circuit structure of an audio apparatus. It is a graph which shows a standard sound pressure curve and a perceived sound pressure curve. It is a block diagram which shows the detailed structure of a sound pressure adjustment part, an interpolation process part, and a zone | band synthetic | combination part. It is the schematic which shows the relationship between the waveform of the basic sampling function used in the interpolation part according to band of this invention, and the waveform of a control sampling function. It is a block diagram which shows the circuit structure of the interpolation part according to zone | band. It is the schematic which shows the positional relationship of the data according to four bands, and the attention point. It is a block diagram which shows the detailed structure of the interpolation part according to zone | band. It is the schematic which shows the interpolation process using the basic sampling function by the interpolation part according to band by this invention. It is the schematic which shows the interpolation process using the control sampling function by the interpolation part according to band by this invention. It is the schematic which shows the waveform of the sampling function when a variable parameter is changed. It is the schematic which shows the frequency characteristic when a variable parameter is changed. It is a block diagram which shows the circuit structure of the audio apparatus by other embodiment.

Explanation of symbols

1 Audio equipment (acoustic equipment)
2a Hearing test part (Hearing test means)
2b Acoustic processing unit (adjustment means)
9 Control unit (specifying means)
10 Confirmation signal input section (confirmation signal input means)
11 Detection sound output section (inspection sound output means, minute sound generation means)
13 Band-specific sound pressure coefficient calculation unit (generation means)
103 Selection part (selection means)

Claims (14)

Auditory inspection means for specifying a perceived sound pressure level, which is the minimum sound pressure level detected by the user, for each frequency band, and inspecting the user's auditory characteristics;
The music to be listened to by the user is input as an acoustic signal from the input unit, and the adjusting unit adjusts the frequency characteristic of the acoustic signal to a frequency characteristic suitable for the auditory characteristic of the user based on the output result from the auditory examination unit. And
The auditory test means stores a statistical standard sound pressure curve representing a minimum sound pressure level heard by a general user for each frequency band, and a standard sound pressure level of the standard sound pressure curve; Calculating a sound pressure coefficient, which is a ratio to the perceived sound pressure level, for each frequency band examined by the user;
A relational expression between the sound pressure coefficient and the frequency band is generated for each of the examined frequency bands, a perceived sound pressure level tendency is estimated based on the plurality of relational expressions, and the user hears from the estimation result. A sound device that amplifies a difficult sound pressure level in a frequency band of the sound signal by the adjusting means. The hearing test means includes
Inspection sound output means for presenting the inspection sound to the user while increasing the sound pressure level of the inspection sound for each frequency band until there is a response from the user to the inspection sound;
Specifying means for specifying the perceived sound pressure level for each frequency band according to a response from the user,
The adjusting means includes
A band separation unit that separates the input acoustic signal into a plurality of frequency bands, and for each frequency band separated by the band separation unit, the sound pressure level in the frequency band that is difficult for the user to hear is obtained from the estimation result. The acoustic device according to claim 1, wherein the acoustic device is increased or decreased based on the basis. The hearing test means includes
Based on a relational expression between the sound pressure coefficient and the frequency band, the perceptual sound pressure level tendency in the frequency band other than the frequency band in which the perceived sound pressure level is specified is calculated to calculate the perception of the entire frequency band. A generating means for generating a perceived sound pressure curve indicating a sound pressure level tendency as the estimation result;
The acoustic device according to claim 2, wherein the adjustment unit increases or decreases a sound pressure level for each of the frequency bands based on the perceived sound pressure curve. 4. The acoustic apparatus according to claim 3, wherein the perceived sound pressure curve is represented by an nth order polynomial relating to frequency, and a sound pressure adjustment level at each frequency is generated based on the nth order polynomial. The acoustic device according to claim 3 or 4, wherein the auditory test means stores a plurality of the perceptual sound pressure curves generated in advance. The acoustic apparatus according to claim 5, further comprising a selection unit that allows a user to select a desired perceptual sound pressure curve among the plurality of perceptual sound pressure curves stored in the auditory inspection unit. The inspection sound output means includes a minute sound generation means for generating a minute sound for auditory characteristic inspection, and a confirmation signal input means for causing the user to input a confirmation signal when the user perceives the minute sound. The acoustic device according to any one of claims 2 to 6, further comprising: Auditory inspection step of identifying perceived sound pressure level, which is the minimum sound pressure level detected by the user, for each frequency band by the auditory inspection means, and inspecting the user's auditory characteristics;
A standard sound pressure level of the standard sound pressure curve and the perceived sound are recorded by the auditory test means storing a statistical standard sound pressure curve representing a minimum sound pressure level heard by a general user for each frequency band. A calculation step of calculating a sound pressure coefficient, which is a ratio to the pressure level, for each frequency band examined by the user;
The music to be listened to by the user is input as an acoustic signal from the input unit , and the frequency characteristic of the acoustic signal is adjusted by the adjusting unit based on the output result from the auditory test unit that performs the auditory test step. An adjustment step for adjusting to a frequency characteristic suitable for
In the adjustment step, a relational expression between the sound pressure coefficient and the frequency band is generated for each of the examined frequency bands, a perceived sound pressure level tendency is estimated based on the plurality of relational expressions, and the estimation result A sound pressure level in the frequency band of the sound signal that is difficult for the user to hear is amplified by the adjusting means. The hearing test step includes
A test sound output step of presenting the test sound to the user while increasing the sound pressure level of the test sound for each frequency band until there is a response from the user to the test sound;
A step of specifying the perceived sound pressure level for each frequency band according to a response from the user,
The adjustment step includes
The acoustic signal from the input unit is separated into a plurality of frequency bands by a band separation unit, and the sound pressure in a frequency band that is difficult for the user to hear for each of the frequency bands separated by the band separation unit by the adjustment unit. The sound adjustment method according to claim 8, wherein the level is increased or decreased based on the estimation result. The hearing test step includes
Based on a relational expression between the sound pressure coefficient and the frequency band, the perceptual sound pressure level tendency in the frequency band other than the frequency band in which the perceived sound pressure level is specified is calculated to calculate the perception of the entire frequency band. A generation step of generating a perceived sound pressure curve indicating a sound pressure level tendency as the estimation result is provided after the specifying step,
The adjustment step includes
The sound adjustment method according to claim 9, wherein the sound pressure level is increased or decreased for each frequency band based on the perceived sound pressure curve. The acoustic adjustment method according to claim 10, wherein the perceived sound pressure curve is represented by an nth order polynomial relating to frequency, and a sound pressure adjustment level at each frequency is generated based on the nth order polynomial. The acoustic adjustment method according to claim 10 or 11, wherein in the auditory test step, a plurality of the perceptual sound pressure curves are generated and stored in advance. In the auditory test step, the perceptual sound pressure curves of a plurality of users are generated and stored in advance, and the user perceives the perception suitable for the user from the stored perceptual sound pressure curves when reproducing the sound signal. The sound adjustment method according to any one of claims 10 to 12, wherein the sound pressure level is adjusted by selecting a sound pressure curve. In the auditory inspection step, a minute sound is generated by a minute sound generating means, and when the user perceives the minute sound, the user inputs a confirmation signal via the confirmation signal input means, and the perceived sound pressure level is set. It specifies. The acoustic adjustment method of any one of Claims 8-13 characterized by the above-mentioned.

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