WO2006068345A1

WO2006068345A1 - Equalization apparatus and method based on audiogram

Info

Publication number: WO2006068345A1
Application number: PCT/KR2005/000766
Authority: WO
Inventors: Dae-Hoon Kwon
Original assignee: Dae-Hoon Kwon
Priority date: 2004-12-23
Filing date: 2005-03-17
Publication date: 2006-06-29
Also published as: CN101128877A; EP1829039A4; MX2007006484A; US7936888B2; KR100707339B1; RU2007118634A; AU2005319951B2; KR20060072555A; CA2587456A1; JP2008520155A; US20080008070A1; CN101128877B; EP1829039A1; JP4558044B2; RU2348990C1; AU2005319951A1

Abstract

Disclosed is an equalization apparatus and method based on audiogram. The equalization method includes the steps of a) outputting a reference sound having reference frequency and intensity for approximate assumption of auditory threshold, b) determining a start sound corresponding to an assumed value of the auditory threshold while calling a sound having intensity different from a prior sound at a sound source memory depending on whether a user has received an answering signal in response to the reference sound, c) outputting a first test sound whose intensity is controlled at a value set prior to the start sound, having the reference frequency, d) calling a test sound having intensity and frequency different from the prior sound at the sound source memory depending on whether the user has received the answering signal, e) storing data on reception of the answering signal of the user in response to the test sound, f) repeating the steps d) to e), g) determining the auditory threshold per previously set frequency band using the reception data of the answering signal, and h) performing equalization depending on the auditory threshold per the determined frequency.

Description

EQUALIZATION APPARATUS AND METHOD BASED ON AUDIOGRAM

TECHNICAL FIELD

The present invention relates to an equalization apparatus and method based on

audiogram, and more particularly, to an equalization apparatus and method based on

audiogram, in which individual audiogram is tested per personal frequency band using

self-calibration and a Random Bekesy tracing algorithm, and equalization is performed

based on the tested audiogram to obtain an optimal sound and an optimal hearing

protection function.

BACKGROUND ART

Statistically, it is assumed that 0.1% to 0.2% per population corresponds to

profound hearing loss that cannot be heard, 1% to 2% per population corresponds to

moderate and severe hearing loss, and 10% to 15% corresponds to mild hearing loss.

People corresponding to the range of the mild hearing loss have a difficulty in hearing a

sound of 2OdB to 4OdB but can make conversation with another people close to them

without difficulty. Therefore, most of the people corresponding to the range of the mild

hearing loss rarely go to hospital because they do not recognize seriousness of their

hearing loss. However, if the people corresponding to the range of the mild hearing loss R2005/000766

continuously use an audio player with excessively great volume, their hearing loss may become the moderate hearing loss. In worst case, their hearing loss may become the

severe hearing loss or the profound hearing loss.

In modern society, many people use various audio players, such as TV, the AM-

FM Radio, CD player, MP3 player, audio cassette, PC, and language player.

The audio players currently selling in the market have a volume amplifying

function enough to cause hearing loss. Since most of users of the audio players tend to

listen to music with high volume, their hearing loss becomes serious to cause the mild

hearing loss. Particularly, since people who much like music tend to listen to music with

high volume, those people are more serious in hearing loss to cause moderate hearing

loss or profound hearing loss.

The related art audio player has caused more serious hearing loss because it

played audio regardless of individual audiogram.

Auditory cells of a cochlear canal have frequency bands and volume, which are

determined. Audiogram is a distribution of sense per frequency of the auditory cells,

which is obtained by hearing test. People have unique audiogram like fingerprint or

DNA structure. Such audiogram may be varied due to aging or excessive great volume.

For example, supposing that anyone listened to a sound of a frequency of IkHz at the

intensity of 8OdBHL or greater for several hours, its particular auditory cell that handles

the sound of IkHz is exposed to an excessive sound, thereby causing sudden hearing loss. Supposing that anyone who likes a sharp and stimulus sound repeatedly listens to a sound of a frequency of 1OkHz with high volume, its hearing may cause a functional

hearing loss for the frequency band of 1OkHz.

Meanwhile, FIG. 1 illustrates the result of volume control of the related art audio

player. In FIG. 1, a first group 100 and a second group 102 are shown. The first group

100 has a threshold of OdBHL around IkHz in an outer hair cell group while the second group 102 has a threshold of 3OdBHL.

Since the related art audio player linearly controls volume, it is likely that the

first group 100 may be damaged. In other words, if volume is controlled at 9OdBHL, the

second group 102 may feel less fatigue because it is exposed at 6OdBHL. However, the first group 100 may be damaged due to volume distortion and fatigue because it is

overexposed at 9OdBHL.

To avoid loss of the auditory cells, which may be caused by linear volume

control of the audio player, equalization may be performed to enable individual volume control per frequency band.

Generally, an equalizer allows a user to listen to music at a desired sound tone.

For example, anyone who likes a clear and elegant sound can volume the high frequency

band of the equalizer up to listen to a desired sound. Anyone who likes a magnificent

and powerful sound can volume the low frequency band of the equalizer up to listen to a

desired sound. In addition to making user's desired sound tone, the equalizer is used for medical

treatment such as an aural aid and an artificial cochlear canal.

In case of hearing loss patients who need an aural aid or an artificial cochlear

canal, the equalizer should essentially be controlled depending on their audiogram after

5 testing their hearing per frequency. This is because that hearing becomes worse if a

hearing loss patient having no great hearing loss for a frequency band of 1OkHz is

supplied with a sound through an aural aid and an artificial cochlear canal that did not

perform equalization (referred to as "fitting" in acoustics) for a frequency band of

1OkHz. l o However, if it is intended to provide an audio player based on audiogram of a

user using the equalizer, it is difficult to provide such an audio player according to an

equalization method based on audiogram in the existing audiogram test method.

hi the related art audiogram test method, a particular frequency band is selected

by manipulation of a tester based on six frequency bands of 250Hz, 500Hz, 1000Hz,

15 2000Hz, 4000Hz, and 8000Hz. Afterwards, the intensity of a test sound is manually

controlled to determine an auditory threshold in the particular frequency band, hi this

way, another frequency band is selected to determine its auditory threshold.

In other words, in the related art audiogram test method, since the step of selecting a frequency of the tester, the step of suggesting a test sound, and the step of

20 determining the auditory threshold depending on response of the test sound of a testee are separately performed, maximum time as much as 50 minutes is required to

determine the auditory threshold in six frequency bands as above. Therefore, if the related art audiogram test method is applied to the audio player, it is difficult for the user to select the frequency of the audio player, receive the test sound, and determine the

auditory threshold.

Particularly, time required for testing the auditory threshold becomes long as a

frequency band is subdivided. Therefore, it is difficult to provide the audio player in

which equalization is performed based on the related art audiogram test method.

Furthermore, if the test sound is provided by controlling the intensity only in a

state that a particular frequency is selected, a test error may greatly occur due to

adaptation and selective attention of the user, thereby making exact audiogram test difficult.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further

understanding of the invention and are incorporated in and constitute a part of this

specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

In the drawings:

FIG. 1 illustrates the result of volume control of a related art audio player; FIG. 2 illustrates an equalization apparatus based on audiogram according to the

preferred embodiment of the present invention;

FIG. 3 illustrates a module of a controller according to the preferred embodiment

of the present invention;

FIG. 4 illustrates the standard for determining a final auditory threshold according to the preferred embodiment of the present invention;

FIG. 5 illustrates the result of volume control of an audio player in which

equalization based on audiogram is performed according to the preferred embodiment of

the present invention; and

FIG. 6 is a flow chart illustrating equalization based on audiogram according to the preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

TECHNICAL PROBLEMS

Accordingly, the present invention is directed to an equalization apparatus and

method based on audiogram that substantially obviates one or more of the problems due

to limitations and disadvantages of the related art.

An object of the present invention is to provide an equalization apparatus and

method based on audiogram, in which an optimal sound and an optimal hearing

protection function can be given to a user while minimizing audiogram test time. Another object of the present invention is to provide an equalization apparatus

and method based on audiogram, in which time required for audiogram test can be

minimized even in case that a frequency band is subdivided.

Another object of the present invention is to provide an equalization apparatus

and method based on audiogram, in which an optimal test start sound can be set

automatically without manual manipulation of a user in selecting the test sound, so as to

reduce time required for audiogram test.

Another object of the present invention is to provide an equalization apparatus and method based on audiogram, in which an auditory threshold per frequency band is

determined for volume control so that a clear sound may be provided at low power.

Another object of the present invention is to provide an equalization apparatus

and method based on audiogram, in which the step of allowing a user to select a

frequency is omitted so as not to cause adaptation of hearing or selective attention,

thereby enabling exact audiogram test.

TECHNICAL SOLUTIONS

To achieve these and other advantages and in accordance with the purpose of

the present invention, as embodied and broadly described, in an equalization method

based on audiogram using an equalization apparatus including a sound source memory

calibrated at a constant step of dBHL and storing sound source data having a plurality of

frequency bands for one dBHL, a sound chip, a controller calling the sound source data, a speaker, and an equalizer, the equalization method includes the steps of a) outputting a reference sound having reference frequency and intensity for approximate assumption of

auditory threshold, b) determining a start sound corresponding to an assumed value of the auditory threshold while calling a sound having intensity different from a prior

sound at a sound source memory depending on whether an answering signal of a user to

the reference sound is received, c) outputting a first test sound whose intensity is

controlled at a value set prior to the start sound, having the reference frequency, d)

calling a test sound having intensity and frequency different from those of the prior

sound at the sound source memory depending on whether the answering signal of the

user to the test sound is received, e) storing reception data on the answering signal of the

user to the test sound, f) repeating the steps d) to e), g) determining the auditory

threshold per previously set frequency band using the reception data of the answering

signal, and h) performing equalization depending on the determined auditory threshold

per frequency, wherein the controller calls a sound source while randomly changing the

frequency depending on a predetermined Random Bekesy tracing algorithm.

In another aspect of the present invention, an equalization apparatus based on audiogram includes a sound source memory calibrated at a constant step of dBHL and

storing sound source data having a plurality of frequency bands for one dBHL, a

controller calling a reference sound for approximate assumption of user's auditory

threshold and a sound source from the sound source memory during audiogram test, the sound source having intensity and/or frequency controlled depending on whether an

answering signal of a user is received, storing reception data on the answering signal of the user to determine user's auditory threshold per frequency band, performing

equalization depending on the determined auditory threshold, a sound chip whose output

level is controlled at a constant step by an output level control program, receiving an output level changing signal of the controller to change the output level, and an

equalizer equalized by the controller, wherein the controller calls the sound source while

randomly changing the frequency depending on a predetermined Random Bekesy

tracing algorithm.

APPLICABLE ADVANTAGES

The equalization apparatus and method based on audiogram according to the

present invention has the following advantages.

Since both a sound chip having output intensity controlled at a predetermined

step and a sound source file based on an equal loudness contour of ISO226:2003 are

used, audiogram can exactly be tested and time required for setting a first test sound can

be reduced.

Further, since a frequency band is randomly changed during audiogram test,

adaptation or selective attention for a particular frequency band can be removed to determine exact auditory threshold.

Further, since an audio player is provided in which equalization based on exact and prompt auditory threshold is performed, an optimal sound and an optimal hearing

protection function can be given to the user.

Finally, since the auditory threshold is determined per frequency band for

volume control, a clear sound can be provided at low power.

5

BEST MODE FOR CARRYING OUT THE INVENTION

Reference will now be made in detail to the preferred embodiments of the

present invention, examples of which are illustrated in the accompanying drawings.

FIG. 2 illustrates an equalization apparatus based on audiogram according to the

l o preferred embodiment of the present invention.

As shown in FIG. 2, an equalization apparatus based on audiogram includes a

controller 200, a sound source memory 202, a test sound generator 204, a speaker 206,

an answering switch 208, a memory 210, and an equalizer 212.

The controller 200 receives a start signal for testing audiogram of a user and

15 calls a predetermined reference sound from the sound source memory 202 to output the

reference sound to the outside through the test sound generator 204 and the speaker 206. A microprocessor maybe used as the controller 200.

The controller 200 calls a sound source of different intensity dBHL from the

sound source memory 202 depending on whether an answering signal is received from

20 the answering switch 208 while audiogram test continues. Then, the controller 200 processes the received answering signal to determine an auditory threshold of the user.

Particularly, the controller 200 randomly changes a frequency of the sound

source depending on a Random Bekesy tracing algorithm to determine the auditory

threshold. The step of determining the auditory threshold will be described later in more

detail.

The sound source memory 202 stores the sound source given to the user. In the

present invention, a test sound calibrated at a step of 2.5dBHL is stored in the sound

source memory 202 per frequency band. The test sound generator 204 corresponds to a sound chip, and decodes the

sound source called from the sound source memory 202 to output the test sound through

the speaker.

The sound source memory 202 and the test sound generator 204 according to the

present invention are designed to enable self-calibration in which an optimal test start

sound can be selected during audiogram test.

Hereinafter, self-calibration and the Random Bekesy tracing algorithm according to the present invention will be described in more detail.

Self-Calibration

Generally, in a sound chip which uses an AC97 (that is a standardized sound

chip built in a main board of a PC in a chip on board type) audio codec and an audio codec similar to the AC97 audio codec, if a volume controller on a control board of the

PC is used, it is impossible to finely control the output intensity of the sound chip.

Therefore, the present invention has been intended to control the output intensity

of the sound chip at a step of 1OdB based on an AC97 output control algorithm in an

application program of the controller 200. Also, the relation between the output level

and the output sound pressure has been set as shown in the following Table 1.

(Reference Tone = relative intensity of IkHz, OdB)

Afterwards, a wave file list is prepared, which is calibrated at a step of 2.5dBHL

on the standard of dBHL based on an equal loudness contour of ISO226:2003.

As described above, the test sound calibrated at a step of 2.5dBHL is stored in

the sound source memory 202. At this time, the test sound is preferably stored in a wave file type. For example, the sound source memory 202 is provided with wave file folders

from 5OdBHL to OdBHL at a step of 2.5dBHL. The test sound divided into sound

sources per frequency band (for example, 6, 11, 17, and 34 bands) used in audiogram

test is stored in each of the wave file folder. dBHL (dB hearing level) means that a dB sound pressure level (dB SPL), i.e.,

the physical standard of sound is converted into the psychological acoustic standard, hi

the present invention, the sound source data is calibrated based on the equal loudness

contour of ISO226:2003 finally revised on August, 2003.

After the output intensity of the sound chip is controlled and the wave file prepared based on the equal loudness contour of ISO226 is stored as described above,

self-calibration is performed to determine the optimal test start sound for approximate

assumption of left and right auditory thresholds.

Li case of self-calibration, the original AC97 output intensity level is 100 (based

on the maximum output level value of 10000, see Table 1). At this time, the wave file

first called from the sound source memory 202 by the controller 200 is IkHz, 5OdBHL (reference sound).

In the audiogram test according to the present invention, if the user does not

hear the reference sound, the test sound higher than the previous test sound by 1 OdBHL

is suggested. To this end, the controller 200 changes the AC97 output intensity level

from 100(64dB SPL) to 10000(104dB SPL). In this case, the test sound higher than the first test sound by 4OdB is provided. Then, the controller 200 calls a wave file of IkHz,

2OdBHL. If the output level is changed from 100 to 10000 as above to output a file of

2OdBHL, a sound having the intensity of 6OdB higher than the reference sound by 1 OdBHL is given to the user. If the user does not answer to the sound of 6OdBHL, the

5 controller 200 outputs the sound source of 3OdBHL in a state that the output level is

maintained at 10000, so that the user can hear the sound of 7OdBHL.

If the user does not recognize the sound, the controller 200 gives the sound to the user while increasing the intensity of the sound by 1 OdBHL. The controller 200

determines the sound corresponding to the first answering signal of the user as the start

i o sound and stores the start sound in the memory 210.

Meanwhile, if the user generates the answering signal to the sound of IkHz,

5OdBHL output at the first output level of 100, the controller 200 calls the sound source

of 4OdBHL (frequency of IkHz) from the sound source memory 202 without changing

the output level. If the answering signal to the sound source of 4OdBHL is not received,

15 the controller 200 determines the sound source as the start sound. By contrast, if the

answering signal to the sound source of 4OdBHL is received, the controller 200 outputs the sound source of 3OdBHL (frequency of IkHz) without changing the output level.

The controller 200 repeatedly performs the step of determining the start sound or the

step of lowering the intensity of the test sound.

20 As described above, the controller 200 performs self-calibration that determines the start sound by differently outputting the test sound at a step of 1 OdBHL depending on whether the user has recognized the test sound. Therefore, the step of determining the

start sound can be shortened.

In other words, in the related art audiogram test method, inconvenient manual

manipulation of the tester has been essentially required to determine the test start sound.

However, in the present invention, the output intensity of the sound chip is controlled at

a step of 1OdB and the optimal test start sound can easily be found by changing the

output level of the controller 200. Therefore, in the present invention, the audiogram test

time can remarkably be reduced.

Although it has been described that AC97 is used as the sound chip and the

wave file is used as the sound source file, the present invention is not limited to such

case.

Random Bekesy tracing algorithm

In the present invention, after self-calibration is performed, the Random Bekesy

tracing algorithm is used in testing audiogram.

The Random Bekesy tracing algorithm in testing audiogram is to provide a pure

tone and test audiogram depending on whether a testee answers to the pure tone.

However, as described above, in the related art audiogram test method (Bekesy method),

the intensity of the test sound is only controlled and the controlled intensity of the test

sound is given to the testee in a state that the tester previously sets a frequency band. If the auditory threshold is finally determined in the corresponding frequency band, the next frequency band is set. In this way, the same steps are repeatedly performed. Li this

case, it takes much time to test audiogram, and adaptation and selective attention occur

in the test frequency band so as not to obtain the reliable test result. Particularly, left and right audiograms of 34 bands are tested based on the

related art Bekesy tracing algorithm, the expenditure of time has occurred in that it takes

three hours.

In the present invention, the controller 200 provides the test sound by

differently setting the frequency band based on a predetermined algorithm during the audiogram test without manipulation of the user. Then, the Random Bekesy tracing

algorithm is used to determine the auditory threshold in a particular frequency band

depending on whether the user receives the test sound.

hi more detail, as described above, if the test start sound determined by self-

calibration is stored in the memory 210, the controller 200 calls a sound (first test

sound) of IkHz from the sound source memory 202 and provides the user with the

sound. In this case, the sound corresponds to the intensity higher than that of the prior

start sound by a predetermined value of OdBHL to 15dBHL. Preferably, a predetermined value of 15dBHL is used for exact audiogram test.

For example, if the first test sound is provided at the intensity higher than that

of the start sound by 15dBHL, the controller 200 outputs a test sound (second test sound) smaller or greater than the first test sound by 5dBHL depending on response of

the testee.

At this time, the controller 200 calls the second test sound of a frequency band from the sound source memory 202, the frequency band being different from IkHz that

is a frequency band of the first test sound.

Afterwards, the step of varying the sound source intensity of the test sound by

5dBHL depending on response of the user is repeated. If an ascending threshold and a

descending threshold of the auditory threshold are determined per predetermined

frequency band, the controller 200 determines a point corresponding to 2.5dBHL of the

ascending threshold and the descending threshold as the auditory threshold at the

frequency band.

If the auditory threshold is determined as above, the controller 200 controls the

output of the equalizer 212 to play the sound based on audiogram of the user.

Meanwhile, although not shown, the equalization apparatus according to the

present invention may be provided with a user interface portion that can select the

number of frequency bands for determining the auditory threshold. Therefore, the user

can select the number of frequency bands to be tested, and the controller 200 can

determine the auditory threshold depending on the selected frequency band.

As described above, since the controller 200 of the present invention randomly

changes the frequency band of each test sound and calls the changed frequency band from the sound source memory 202, the user's manipulation for changing the frequency

is not required. Also, it is possible to avoid distortion of audiogram due to adaptation and selective attention of the testee in the related art Bekesy tracing algorithm in which

audiogram is tested by varying only the intensity of the sound at one frequency band.

5 FIG. 3 illustrates a module of the controller according to the preferred

embodiment of the present invention.

As shown in FIG. 3, the controller 200 of the present invention includes a sound source calling module 300, an output level control module 302, an answering signal

reception module 304, an auditory threshold determining module 306, and an

i o equalization calculating module 308.

The sound source calling module 300 outputs a reference sound (eg., IkHz,

5OdBHL) and a test sound previously set depending on response of the user from the

sound source memory 202 if the audiogram test start signal of the user is received

thereto.

15 Particularly, the sound source calling module 300 outputs the sound source having the intensity different from that of the prior test sound depending on response of

the test sound of the user in the step of determining the auditory threshold and calls the

test sound of a frequency band from the sound source memory 202, the frequency band

being different from a prior frequency band given to the user.

20 The output level control module 302 controls the output level of the sound chip 66

during self-calibration.

In the present invention, to provide the test sound having no distortion based on

the equal loudness contour of ISO226:2003, the sound source data is stored at a step of

2.5dBHL using a wave file of 5OdBHL as a maximum value. As described above, the

sound source of the reference sound of IkHz, 5OdBHL (based on the maximum output level of 10000) is called using the first output level of 100 in case of self-calibration.

However, if the answering signal of the user to the reference sound is not

received, a sound higher than the prior sound by 1 OdBHL is required. Since the source

sound file of 6OdBHL does not exist, the output level control module 302 controls the

output level to 10000 to provide such a test sound. The sound source calling module 300 calls the sound source of IkHz, 2OdBHL to provide the user with the test sound of

6OdBHL.

The answering signal reception module 304 receives the answering signal of the

user who has recognized the test sound, which is output through the answering switch

208. Then, the answering signal reception module 304 transmits the received answering

signal to the sound source calling module 300 or the output level control module 302.

Furthermore, if the answering signal of the user is not received for a

predetermined time after the test sound is provided, the answering signal reception

module 304 determines such no-answering signal to the sound source calling module

300 or the output level control module 302. The sound source calling module 300 and the output level control module 302

call different sound source data or control the output level depending on the signal

transmitted from the answering signal reception module 304.

The auditory threshold determining module 306 determines the ascending threshold and the descending threshold per frequency band depending on response of the

user to the test sound whose intensity is controlled by 5dBHL (frequency is randomly

changed). The auditory threshold determining module 306 determines a middle value

between the ascending threshold and the descending threshold as the final auditory

threshold of the corresponding frequency band.

FIG. 4 illustrates the standard for determining the final auditory threshold

according to the preferred embodiment of the present invention. As shown in FIG. 4, the

auditory threshold determining module 306 can determine the auditory threshold per frequency band depending on six standards.

In FIG. 4, a vertical line represents a step of 5dBHL, a horizontal line represents

the number of test sounds, 0 represents answering, and 1 represents no-answering.

In more detail, a first example 400 represents no-answer(O), answer(l), and no-

answer(O) in order. If the first test sound of 3OdBHL is provided at a frequency band of

250Hz, the first example 400 represents no-answer(O). If the test sound is greater than

the prior test sound by 5dBHL (35dBHL), the first example 400 represents answer(l). If

the test sound is lower than the prior test sound by 5dBHL (3OdBHL), the first example 400 represents no-answer(O). The auditory threshold determining module 306 stores data on the answering signal of the user in the memory 210 with each frequency and intensity. At the frequency band of 250Hz, the descending threshold is determined as

3OdBHL, the ascending threshold is determined as 35dBHL, and the final auditory

threshold is determined as 32.5dBHL.

The test sounds of 3OdBHL, 35dBHL, and 32.5dBHL are randomly(not

successively) provided to the user during the audiogram test depending on the Random

Bekesy tracing algorithm.

A second example 402 represents answer(l), no-answer(O), and answer(l) at a

particular frequency band. At this time, the auditory threshold determining module 306

determines the middle value among the test sounds in case of answer(l) and no-

answer(O), and answer(l) as the final auditory threshold.

A third example 404 represents no-answer(O), answer(l), and answer(l). hi the

third example, the user who does not respond to the first test sound at least twice

responds to the test sound having the same intensity as that of the first test sound.

In this case, the auditory threshold determining module 306 determines the test

sound lower than the final test sound by 2.5dBHL as the final auditory threshold.

hi a fourth example 406, the user irregularly represents answer(l) and no-

answer(O) to the test sound equal to the first test sound without responding to the first

test sound. In this case, the auditory threshold determining module 306 determines the final test sound as the descending threshold and determines the value greater than the descending threshold by 2.5dBHL as the final auditory threshold.

Meanwhile, in a fifth example 408, the user responds to the first test sound but

does not respond to the next test sound having the same intensity as that of the first test sound at least twice, hi this case, the auditory threshold determining module 306 determines the test sound greater than the final test sound by 2.5dBHL as the final

auditory threshold.

Finally, in a sixth example 410, the user responds to the first test sound twice

among three times. In this case, the auditory threshold determining module 306

determines the first test sound as the ascending threshold and determines the test sound

lower than the first test sound by 2.5dBHL as the final auditory threshold.

The aforementioned six determining standards include all of possible cases, and

audiogram test subject to the Random Bekesy tracing algorithm is available in

accordance with the standards.

If the auditory threshold per frequency band is determined by the auditory

threshold determining module 306 as described above, the equalization calculating

module 308 performs equalization based on the final auditory threshold.

Since the equalizer is well known, its description will be omitted in the present invention.

FIG. 5 illustrates the result of volume control of the audio player in which equalization based on audiogram is performed according to the preferred embodiment of

the present invention. The result of volume control of FIG. 5 will be described in

comparison with that of FIG. 1.

In volume control of the related art audio player, since volume control is

linearly performed, for example, volume is increased to 9OdBHL at all the frequency

bands (see FIG. 1), distortion of sound and fatigue may occur in a particular auditory

cell (first group 100). However, in the present invention, since volume control is

performed after equalization, volume control in the range of 75dBHL can be performed

respectively in the first group 100 and the second group 102. In this case, cell groups

susceptible to intensity are protected while cell groups less susceptible to intensity may

be provided with sound of stronger intensity to allow the user to listen to a desired

sound.

FIG. 6 is a flow chart illustrating equalization based on audiogram according to

the preferred embodiment of the present invention.

Referring to FIG. 6, the controller 200 outputs a reference sound of IkHz,

5OdBHL in step S600, and determines whether the answering signal of the user to the

reference sound is received in step S602. If the answering signal is received, the

controller 200 outputs a sound having intensity lower than that of the reference sound by

1 OdBHL in step S604. The controller 200 determines whether the answering signal of

the user to the sound of 4OdBHL is received in step S606. If the answering signal is R2005/000766

received, the controller 200 repeats the step S604. If the answering signal is not received,

the controller 200 determines the test sound at that time as the start sound and stores the

test sound in the memory 210 in step S612.

Meanwhile, in step S602, if the answering signal is not received, the controller

200 outputs a sound having intensity higher than that of the reference sound by 1 OdBHL

in S608. The controller 200 determines whether the answering signal of the user to the

sound having intensity higher than that of the reference sound by 1 OdBHL is received in

step S610. If the answering signal is not received, the controller 200 repeats the step

S608. If the answering signal is received, the controller 200 determines the sound at that

time as the start sound in step S612.

If the start sound is determined as above, the controller 200 outputs the first test

sound having intensity greater than that of the start sound by 15dBHL in step S614 and

determines whether the user responds to the first test sound in step S616.

If the user responds to the first test sound, the controller 200 determines

whether all the auditory thresholds have been completely determined per previously set

frequency band in S 618. If the auditory thresholds have not been completely determined,

the controller 200 provides the user with the test sound having intensity lower than that

of the prior test sound by 5dBHL in step S620.

Meanwhile, if the user does not respond to the test sound in step S616, the

controller 200 determines whether all the auditory thresholds have been completely determined in step S622. If all the auditory thresholds have not been completely determined, the controller 200 provides the user with the test sound having intensity

greater than that of the prior test sound by 5dBHL in step S624.

As described above, after the test sound controlled at a step of 5dBHL in

comparison with the prior test sound is provided to the user, the steps S618 to S620 or the steps S622 to S624 are repeated depending on whether the answering signal of the

user is received.

If all the auditory thresholds are completely determined in the steps S618 and

S622, the controller 200 stores the auditory threshold per frequency band in the memory

210 and performs equalization depending on the auditory threshold stored in the

memory 210 in step S626.

As described above, the equalization apparatus and method based on audiogram

according to the present invention has the following advantages.

Since both the sound chip having the output intensity controlled at a

predetermined step and the sound source file based on the equal loudness contour of

ISO226:2003 are used, audiogram can exactly be tested and time required for setting the

first test sound can be reduced.

Further, since the frequency band is randomly changed during the audiogram test, adaptation or selective attention for a particular frequency band can be removed to

determine the exact auditory threshold. Further, since the audio player is provided in which equalization based on exact and prompt auditory threshold is performed, an optimal sound and an optimal hearing

protection function can be given to the user.

Finally, since the auditory threshold is determined per frequency band for

volume control, a clear sound can be provided at low power.

While the present invention has been described and illustrated herein with

reference to the preferred embodiments thereof, it will be apparent to those skilled in the

art that various modifications and variations can be made therein without departing from the spirit and scope of the invention. Thus, it is intended that the present invention

covers the modifications and variations of this invention that come within the scope of

the appended claims and their equivalents.

Claims

WHAT IS CLAIMED IS:

1. An equalization method based on audiogram using an equalization apparatus

including a sound source memory calibrated at a constant step of dBHL and storing sound source data having a plurality of frequency bands for one dBHL, a sound chip, a

controller calling the sound source data, a speaker, and an equalizer, the equalization

method comprising the steps of:

a) outputting a reference sound having reference frequency and intensity for

approximate assumption of auditory threshold;

b) determining a start sound corresponding to an assumed value of the auditory

threshold while calling a sound having intensity different from a prior sound at a sound

source memory depending on whether an answering signal of a user to the reference

sound is received;

c) outputting a first test sound whose intensity is controlled at a value set prior

to the start sound, having the reference frequency;

d) calling a test sound having intensity and frequency different from those of the prior sound at the sound source memory depending on whether the answering signal of

the user to the test sound is received;

e) storing reception data on the answering signal of the user to the test sound;

f) repeating the steps d) to e);

g) determining the auditory threshold per previously set frequency band using the reception data of the answering signal; and h) performing equalization depending on the determined auditory threshold per

frequency,

wherein the controller calls a sound source while randomly changing the frequency depending on a predetermined Random Bekesy tracing algorithm.

2. The equalization method based on audiogram according to claim 1, wherein

the sound chip has maximum output intensity and minimum output intensity which are

divided at a constant step by an output intensity control algorithm, the output intensity

being changed by a predetermined output level, and the sound source memory stores the

sound source data calibrated at a step of 2.5dBHL from 5OdBHL to OdBHL (5OdBHL to

OdBHL mean that intensity of corresponding dBHL is heard at a particular output level).

3. The equalization method based on audiogram according to claim 2, wherein

the step b) includes the steps of i) outputting a sound having intensity greater than the

prior sound by 1 OdBHL if the answering signal of the user to the reference sound is not

received, and storing a sound of corresponding intensity if the answering signal is

received (the stored sound corresponds to a start sound), and j) outputting a sound having intensity lower than the prior sound by 1 OdBHL if the answering signal of the

user to the reference sound is not received, and storing a sound of corresponding intensity if the answering signal is not received (the stored sound corresponds to a start

sound).

4. The equalization method based on audiogram according to claim 3, wherein

the controller calls the sound source data of IkHz, 5OdBHL from the sound source

memory to output the reference sound of IkHz, 5OdBHL to the user at the first output

level, and controls the output level at a high level to output a sound having intensity

greater than the sound of 5OdBHL if the answering signal of the user to the reference sound is not received in the step i).

5. The equalization method based on audiogram according to claim 1, wherein

the first test sound corresponds to a sound having intensity greater than that of the start

sound by 15dBHL, the test sound controlled in the step d) has the intensity difference of

5dBHL from that of the prior test sound, and the controller determines a final auditory

threshold at a band of 2.5dBHL between an ascending threshold and a descending

threshold in a particular frequency band depending on whether the answering signal of

the user is received.

6. The equalization method based on audiogram according to claim 1, further

comprising the step of determining the number of frequency bands for determining the auditory threshold depending on an input signal of the user, wherein the controller calls the sound source data and determines the auditory threshold to correspond to the

number of the determined frequency bands.

7. The equalization method based on audiogram according to claim 6, wherein

the number of the frequency bands corresponds to any one of 6 bands, 11 bands, 17

bands, and 34 bands.

8. An equalization apparatus based on audiogram comprising:

a sound source memory calibrated at a constant step of dBHL and storing sound

source data having a plurality of frequency bands for one dBHL;

a controller calling a reference sound for approximate assumption of user's

auditory threshold and a sound source from the sound source memory during audiogram

test, the sound source having intensity and/or frequency controlled depending on

whether an answering signal of a user is received, storing reception data on the

answering signal of the user to determine user's auditory threshold per frequency band,

performing equalization depending on the determined auditory threshold;

a sound chip whose output level is controlled at a constant step by an output

level control program, receiving an output level changing signal of the controller to

change the output level; and an equalizer equalized by the controller, wherein the controller calls the sound source while randomly changing the

frequency depending on a predetermined Random Bekesy tracing algorithm.

9. The equalization apparatus based on audiogram according to claim 8, wherein the sound source memory stores a plurality of sound source data having a step

of 2.5dBHL from 5OdBHL to OdBHL based on an equal loudness contour of

ISO226:2003, and the controller calls the sound source data of IkHz, 5OdBHL from the

sound source memory to output the reference sound of IkHz, 5OdBHL to the user at the

first output level and controls the output level at a high level if the test sound given to

the user based on the first output level should be greater than 5OdBHL.