JPH10115546A - Method for evaluating sound energy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quantitatively evaluate a sound energy as a digital amount by setting one cycle of a sound of a specific frequency generated with a predetermined sound volume as a pulse value, and evaluating a pulse count which is a quotient of a generation time of the sound by the pulse value as the sound energy of the sound. SOLUTION: A hearing ability of a person who has difficulty in hearing is measured, and an acoustic characteristic of a hearing aid is set in accordance with the ability, whereby a remarkable correction effect is obtained. More specifically, one cycle of a sound of a predetermined frequency generated with a predetermined sound volume is set as a pulse value, and a pulse value, and a pulse count which is a quotient of a generation time of the sound by the pulse value is evaluated as an energy of the sound. For instance, when one cycle of the sound of 500Hz frequency is 1/500sec.=2msec. which is the pulse count, and the generation time is 0.2sec., the sound energy is evaluated to be 0.2/0.002=100 pulses. As the generation time becomes longer, the sound energy is increased. However, the predetermined sound volume is not specifically limited and can be set to a degree whereby a person of normal hearing ability can hear without feeling discomfort.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a novel method for evaluating sound energy. The evaluation method of the present invention can be used, for example, for measuring hearing loss of a hearing-impaired person or correcting it.

[0002]

2. Description of the Related Art A sound wave is a compression wave of a medium, and its amplitude is
It is supposed to determine sound energy. And sound energy
Energy is the pressure fluctuation in the medium of the sound field.
1kHz flat sound of a person with normal hearing
Minimum audible value p for sound of surface wave ₀= 20μPa as reference sound
Pressure. Further, the sound pressure p is set to a sound pressure level of 20 log.
(P / p₀) (Unit: dB).

[0003] Hearing aids are widely used to assist hearing impaired persons. This hearing aid is composed of a microphone that converts sound into an electric signal, an amplifier that electrically amplifies the signal detected by the microphone, and a speaker that converts the amplified electric signal into sound. A variety of shapes such as a mold, a glasses mold, and an in-ear type are commercially available.

[0004] The degree of hearing loss varies from person to person, and hearing aids need to be adjusted to the hearing of each individual. Therefore, recent hearing aids are equipped with a device for amplifying the overall volume and a device for amplifying the low-frequency sound and the high-frequency sound, respectively, or can store the amplification amounts of the sounds of a plurality of frequencies in an internal memory. Such devices have been developed, and the hearing gain of each individual is measured to determine the insertion gain for each of a plurality of frequencies.

[0005] Various proposals have been made for a long time as to how much the insertion gain of a hearing aid is to be increased. Although a method of setting the gain so that the level becomes MCL has been proposed, in recent years, the half-gain rule and the Pogo method obtained by improving the half-gain rule have become mainstream.

The half-gain rule is a method of measuring a hearing level for each frequency and using about half of the hearing level as an insertion gain. For example, take an octave point in the frequency band of 250 Hz to 4 KHz, use an audiometer to listen to each subject with a headphone, measure the hearing level, measure the hearing level, and use the half as an insertion gain to determine the acoustic characteristics of the hearing aid. Set.

As a method of measuring the hearing level, the sound volume is gradually gradually increased from a very small sound such as a pure tone or band noise, and the minimum sound volume perceived by the subject is set as the hearing level. Further, in order to evaluate the hearing aid effect when wearing a hearing aid, it is said that MCL should be measured in a free field using a speaker, and that the MCL of each frequency should match the speech spectrum.

[0008]

However, according to the experiments of the present inventors, when the sounding time is controlled from the speaker and the sound is generated from the speaker, the speaker cone is short in time corresponding to less than one wavelength (one cycle). It was clarified that no vibration occurred or no vibration of the vibrator of the sound level meter occurred, and no sound was generated. This phenomenon occurs regardless of the volume of the amplifier. Even if the volume is increased, no sound is generated.

It has also been confirmed that when the sounding time is increased by an integral multiple of one cycle, the sound from the speaker seems to gradually increase in spite of the fact that the volume of the amplifier is constant. It was confirmed that the sound pressure increased not only by human hearing but also by a sound level meter. If a sound wave is a compression wave of a medium which is an analog quantity, a sound pressure must be generated at the moment when the energy level is displaced. For example, even if a wave of １ ／ wavelength is generated, the sound pressure is generated Should be. Therefore, this is inconsistent with the experimental result that no sound is generated in a short period of one cycle or less.

If the sound wave is a compression wave of a medium,
If the volume of the amplifier is constant, the amplitude should be constant and exhibit a constant sound pressure, but this is inconsistent with the experimental result that the sound pressure increases when the sounding time is prolonged. That is, in the conventional method of evaluating sound pressure as sound energy,
The contradiction as described above occurs. Although the evaluation value uses a sound level meter, it is hard to say that the sound energy is quantitatively evaluated.

In setting the acoustic characteristics of the hearing aid,
Even if a hearing aid set based on the half-gain rule is worn, it is rare that a corrected hearing level as theoretical is given, and it has been difficult to lower the MCL in all frequency bands in the audible range. Furthermore, in the conventional method of setting the acoustic characteristics of a hearing aid, it is insufficient for a hearing-impaired person to hear the meaning of environmental sounds, for example, speech sounds. It is also difficult to avoid a phenomenon called the replenishment phenomenon, in which the width between the MCL and the unpleasant threshold becomes extremely narrow.

The present invention has been made in view of such circumstances, and has as its object to provide a novel sound energy evaluation method so that sound energy can be quantitatively evaluated as a digital quantity. I do. It is used for setting the acoustic characteristics of the hearing aid, and M is used in all frequency bands in the actual audible range.
It is an object of the present invention to make it possible to lower the CL, and to make it possible to recognize the meaning of environmental sounds, respond to physiological changes, and the like.

[0013]

A feature of the sound energy evaluation method of the present invention that solves the above-mentioned problems is that one cycle of a sound of a specific frequency generated at a predetermined volume is set as a pulse value and the sound generation time of the sound is set as a pulse value. The quotient divided by the pulse value is evaluated as the sound energy of the sound.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS For example, a sound of 1000 Hz and 31H
The sound pressure when the sound of z was generated for a predetermined time using the same amplifier with a constant volume was measured.
As shown in the figure, it was clarified that the sound pressure changes depending on the sounding time. It was also found that within this sounding time range, the amount of change in sound pressure was greater for higher frequency sounds. Further, it has been clarified that the sound is not generated in the case of the 31 Hz sound in 30 ms or less.

However, if the sound wave is a compression wave of the medium, a sound pressure must be generated at the moment when the energy level is displaced. If the volume of the amplifier is constant, the amplitude is constant and the sound is constant. It should indicate pressure. This contradicts the above phenomenon. Therefore, it has become clear that there is a contradiction in the conventional method in which sound pressure is regarded as a physical quantity of sound and sound energy is evaluated based on the sound pressure.

On the other hand, as a result of further research, for example, using a sound source with a constant sound pressure, the sounding time is measured at 0.5 ms intervals from 0.5 ms to 100 ms at 0.5 ms intervals, and the sound pressure is measured. When the sounding time is shorter, the change in the sound volume that can be heard with respect to the change in the sounding time is greater in the initial period, and in the latter period when the sounding time is longer, the change in the sound volume that is heard in response to the change in the sounding time is longer. It was also found that the amount was smaller.

Therefore, in evaluating the energy of the sound generated from the sound source, the conventional method of evaluating only the sound pressure on the observer side clearly has a problem, and it is necessary to absolutely evaluate the sound energy. . Therefore, it was recalled that pronunciation time was used as a measure of sound energy evaluation. However, from the above experimental results, it was found that some mathematical processing was required in order to make the sounding time an audible physical quantity. Therefore, as a result of diligent research, one cycle of a sound of a specific frequency generated at a predetermined volume is defined as a pulse value, and the number of pulses, which is a quotient obtained by dividing the sound generation time of the sound by the pulse value, is evaluated as the sound energy of the sound. It was found that the sound energy was absolutely evaluated.

When the hearing ability of the hearing-impaired person is measured using the evaluation method, and the acoustic characteristics of the hearing aid are set accordingly, the MCL at each frequency of the hearing ability of the hearing-impaired person is significantly reduced, and is substantially constant at each frequency. And found that an extremely remarkable correction effect was obtained. The present invention has been completed in this way. In the present invention, one cycle of a sound of a specific frequency generated at a predetermined volume is set as a pulse value, and the number of pulses, which is a quotient obtained by dividing the sound generation time of the sound by the pulse value, is evaluated as the sound energy of the sound. .

For example, one cycle of a sound having a frequency of 500 Hz is 1/500 seconds = 0.002 seconds = 2 milliseconds, which is used as a pulse value. When the sounding time of this sound is, for example, 0.2 seconds, the sound energy is 0.2 / 0.0
Evaluated as 02 = 100 pulses. If the sounding time is one second, the sound energy is 1 / 0.002 = 50
Evaluated as 0 pulse. Of course, the larger this value, the higher the energy level. It should be noted that even if a remainder occurs when the sounding time is divided by the pulse value, the remainder has no meaning and the sound energy is evaluated by the pulse number which is an integer value.

That is, in the present invention, it is assumed that a sound wave is a wave and has a property as a quantum, and the pulse value is treated as a unit quantum of the sound energy. If the sounding time is short, the number of included pulses is small, and the sound energy is small. Also, the longer the sounding time, the larger the number of included pulses and the greater the sound energy. In addition,
The predetermined volume in the present invention is not particularly limited, and can be appropriately set according to the purpose, such as a volume at which a person with normal ears can hear without discomfort. In the case of a sound in which a plurality of frequency components are mixed, sound energy can be evaluated by decomposing the sound into single sounds of each frequency and calculating the number of pulses for each single sound.

When the sound energy evaluation method of the present invention is used for setting the acoustic characteristics of a hearing aid, for example, as will be described later, the hearing of a hearing-impaired person is significantly improved, and an extremely high effect can be obtained. . It can also be used for digital recording. In the current digital recording of compact discs, sound pressure and frequency are digitized by dividing sound waves into unit time, but high-frequency and low-frequency sounds that cannot be heard by human ears due to the capacity are Has been cut. However, if the evaluation method of the present invention is used, the capacity can be reduced, and such inaudible high-frequency and low-frequency sounds can be recorded. Even with such a sound, since the actual sound reaches the eardrum, it may cause some physiological effects on the human body, and the actual sound is brought closer by bringing the recorded sound closer to the actual sound. Can have the same physiological effect as if heard.

The present invention can also be applied to the development of sound input / output devices such as microphones, amplifiers, speakers, and hearing aids, and it is highly likely that input / output devices completely different from conventional input / output systems will appear. Further, it is considered that the present invention can greatly contribute to the study of the effect of sound on a living body.

[0023]

EXAMPLES The present invention will be specifically described below with reference to experimental examples and examples. (Experimental example 1) As a sound source, frequency of 1000 Hz and 31H
Using two types of pure tones from an FM sound source of z, using the same amplifier and speaker, the sounding time is increased from 10 ms for the first time in 10 ms steps to 100 ms, and the sound pressure at each sounding time is increased. Each was measured with a sound level meter. The results are shown in FIG. As shown in FIG.
The low tone has a sound pressure of zero at a sounding time of 30 milliseconds or less, and shows a substantially constant sound pressure of 35 to 40 dB at a sounding time of 40 milliseconds or more. However, for a 1000 Hz high tone, a sound pressure of about 48 dB is generated even when the sounding time is 10 milliseconds, and the sound pressure rises rapidly up to 50 milliseconds and thereafter gradually approaches about 90 dB.

That is, it is clear that the sound pressure changes depending on the length of the sounding time, and the sound pressure greatly differs depending on the frequency even for the same sounding time. (Experimental example 2) Using an FM sound source, 500H through an amplifier and a speaker under the control of a personal computer.
A pure tone of z was generated. The pulse value that is the period of the sound of 500 Hz is 1/500 = 2 milliseconds. Therefore, the sound generation time is increased from 2 milliseconds to 15 milliseconds every 1 millisecond, the output signal from the FM sound source at that time is input to an oscilloscope, and its waveform is observed.
The output voltage from the sound source was measured.

As a result, the waveform is constant even if the sounding time is increased from 2 milliseconds to 15 milliseconds, the output voltage of the FM sound source is constant, and the output from the FM sound source is increased even if the sounding time is increased. The voltage was confirmed to be constant. Next, F
The same experiment was performed by inputting an output signal from the M sound source to an amplifier adjusted to a predetermined volume and inputting an output signal from the amplifier to an oscilloscope. As a result, the waveform is constant even if the sounding time is increased from 2 milliseconds to 15 milliseconds, and the output voltage of the amplifier is also constant. Even if the sounding time is increased, the output voltage from the amplifier is constant. It was confirmed that.

Further, an output signal from the amplifier was input to a speaker, and a sound of 500 Hz was generated from the speaker. Then, a sound level meter was installed at a position 30 cm away from the speaker, and an output signal of the sound level meter was input to an oscilloscope to perform a similar experiment. As a result, it was observed that the waveform of the oscilloscope became larger as the sounding time became longer. The output voltage from the sound level meter also increases with the sounding time. FIG. 2 shows the result of calculating the ratio of the output voltage at each sounding time based on the output voltage when the sounding time is 2 milliseconds.

From FIG. 2, it can be seen that the output voltage of the sound level meter sharply increases until the sounding time reaches about 10 milliseconds, and thereafter increases gradually and approaches a constant value.
From the above experiment, it is clear that the output voltage of the FM sound source and the amplifier is constant even when the sounding time is lengthened, whereas the output voltage of the sound level meter increases as the sounding time increases. In other words, when evaluating the energy of the sound generated from the sound source, the conventional method of evaluating the sound pressure on the observer side clearly has a problem, and it is understood that the sound energy must be absolutely evaluated. .

(Embodiment) Using a pure tone from an FM sound source,
At five frequencies of 50 Hz, 500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz, the sounding time was increased from the one pulse value by one pulse value while increasing the sounding time one pulse at a time. The sound volume is 100d at the maximum value at the position of the subject
B is set.

Specifically, in the case of a 250 Hz sound, the pulse value is 4 milliseconds, so that the sound generation time is increased every 4 milliseconds to 4 milliseconds, and that of a 500 Hz sound is 2 milliseconds to 2 milliseconds. The sound generation time is increased every time, the sound of 1000Hz increases the sound generation time every 1 to 1 millisecond, the sound of 2000Hz increases the sound generation time every 0.5 to 0.5 milliseconds, For the sound of 4000 Hz, the sounding time was lengthened every 0.25 ms to 0.25 ms, and the minimum number of audible pulses that the subject could perceive for each frequency was measured. Table 1 shows the results. A person with normal hearing was also measured in the same manner, and the results are shown in Table 1.

[0030]

[Table 1] As shown in Table 2, while a normal person perceives with one pulse, a hearing-impaired person cannot perceive in a range where the number of pulses is small, and the degree is different depending on the frequency.

Next, the acoustic characteristics of the hearing aid are set based on the above results. At present, there is no hearing aid based on the theory of the present invention. Therefore, for convenience, the acoustic characteristics of the hearing aid were adjusted using a commercially available program hearing aid ("PMC" manufactured by Siemens Hearing Instruments Co., Ltd.) so that the minimum audible pulse number of the hearing-impaired person becomes the minimum audible pulse number of the normal person. Note that a predetermined reference insertion gain is set in advance for this hearing aid.

That is, since the change (increase) of the energy level can be regarded as almost zero after 200 pulses or more,
Zero pulse is determined as the maximum energy level, and as shown in Table 2, the difference pulse number between 200 pulses and the minimum number of audible pulses of a hearing-impaired person is determined, and the ratio is determined for each frequency based on a value of 175 at 250 Hz. Next, the product of the ratio and the reference insertion gain preset for the hearing aid was determined, and a new insertion gain was set so as to be close to the value, thereby setting the acoustic characteristics of the hearing aid.

[0033]

[Table 2] The hearing aid was put on the hearing-impaired person, and the hearing aid was used at 250 Hz, 500 Hz, 1000 Hz, 2000 Hz using an audiometer.
The MCL was measured at five levels of frequencies, Hz and 4000 Hz. The results are shown in Table 4 and FIG.

(Comparative Example) The same hearing-impaired person as in the example was equipped with a hearing aid having a predetermined reference insertion gain used in the example, and was subjected to 250 Hz, 500 Hz,
Hearing levels were measured at five frequencies of 1000 Hz, 2000 Hz and 4000 Hz. Table 3 shows the results.

Based on the obtained hearing level, a new insertion gain is calculated by the half gain rule, and is shown in Table 3.

[0036]

[Table 3] Set the acoustic properties of the hearing aid based on this new insertion gain,
Wear the same subject and use an audiometer for 250
Hz, 500Hz, 1000Hz, 2000Hz and 4
MCL was measured at five levels of 000 Hz. The results are shown in Table 4 and FIG.

(Evaluation)

[0038]

[Table 4] As can be seen from Table 4 and FIG. 3, the method of the comparative example has a certain level of correction effect, but the method of the example has a very low MCL and is much more excellent in the correction effect. It can also be seen that the MCL is substantially constant at each frequency.

As described above, the method of the present invention can obtain a high correction effect, but since the actual commercially available hearing aid is set to be adjusted by the sound pressure, the effect of the evaluation method of the present invention is sufficiently obtained. It is difficult to demonstrate. However, if a hearing aid corresponding to the evaluation method of the present invention is developed, it is expected that the MCL of the above-mentioned hearing-impaired person will be further reduced and that the MCL will be almost constant in all audible frequency ranges. Such a hearing aid is, for example, a hearing aid capable of setting an insertion gain for each frequency according to the number of audible pulses of a hearing-impaired person shown in Table 1. Specifically, for example, in the case of a sound of 2000 Hz, a voltage corresponding to 47 pulses obtained by subtracting one pulse of a normal person from 48 pulses, which is the minimum number of audible pulses, may be set as the insertion gain. That is, 47 pulses are 0.5 × 47 = 23.5.
Since the sounding time is milliseconds, the sound of 2000 Hz
A voltage equivalent to 3.5 milliseconds of sound may be set as the insertion gain.

Thus, early development of a hearing aid corresponding to the evaluation method of the present invention is desired.

[0041]

That is, according to the sound energy evaluation method of the present invention, it is possible to quantitatively treat the original stimulus, the hearing aid output, the hearing, etc., and to activate the physiological functions of the auditory nervous system. It can greatly contribute to future sound research. Further, if the sound energy evaluation method of the present invention is applied to a hearing aid acoustic characteristic setting method, the MCL can be reduced in all frequency bands in the audible range. Also, the dynamic range is widened, and hearing loss can be reliably corrected.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between sound generation time and sound pressure obtained in Experimental Example 1.

FIG. 2 is a graph showing a relationship between a sounding time obtained in Experimental Example 3 and an output voltage ratio of a sound level meter.

FIG. 3 is an audiogram showing MCL of a subject wearing a hearing aid set in Examples and Comparative Examples.

Claims (1)

[Claims] 1. A method according to claim 1, wherein one cycle of a sound of a specific frequency generated at a predetermined volume is defined as a pulse value, and a pulse number which is a quotient obtained by dividing a sound generation time of the sound by the pulse value is evaluated as a sound energy of the sound. Characteristic evaluation method for sound energy.