JP5581475B2 - Application software for sound quality correction function - Google Patents

Description

Environmental noise reduction technology for inner earphones Design technology that uses sound-insulating performance to make sound insulation and transmission characteristics coexist Small sound quality finishing technology for small speakers Knowledge of complex vibration mechanisms of small speakers that play ultra-low sounds The small speakers Effective vibration mode design technology for complex vibration mechanisms and sound quality Signal processing technology for controlling the vibration of small speakers to the best sound quality state Digital acoustic signal processing technology Human hearing characteristics Acoustic signal processing environment for smartphones Environment server for Martphone application software Internet environment

Throughout the entire sentence including the claims, the content in {} has priority over the content outside {}.
{Server XX} is a {function consisting of software and hardware} that provides a {specific application program XX} via the Internet environment.

{Terminal} means {a function to demodulate a recorded sound signal and convert it into an electric sound signal}, that is, a device having a player function, such as {computer, mobile computer, mobile phone, mobile player}, etc. It is.
{Terminal device H} is {a terminal device of a unique product type H} and has a unique {OS and interface of an acoustic signal processing unit}.

The sound device has a function of playing back an acoustic sound that is made up of a {speaker, earphone, power amplifier, signal processing circuit} using an electroacoustic signal that is an output signal of a terminal.
The {acoustic device M} is a {M-specific acoustic device}, and has a {sound quality characteristic and dynamic range characteristic} specific to M. Or {means a collection {M} of acoustic products having similar performance.

The {sound insulation piece} is a sound insulation piece that is attached to the opening of the earphone and provided between the earphone and the hearing. The sound insulation piece has a role of not only insulating the environmental noise entering between the earphone and the outer ear, but also insulating the environmental noise transmitted to the hearing through the earphone body.

A {user} is a person who tries to play music with an audio device and a terminal.

{Application software is {a group of software that functions when installed in a terminal}} and is distributed as a product.

{Standard} {Standard characteristics} {Standardization} is a definition unified by a specific rule or a specific concept, and does not mean an absolutely unified standard. For example, {{position of {0.5 m} on the front axis of the speaker}, {input level {100 mV}, and reproduction frequency range within {+ -6 dB} of reproduction characteristics is from {70 Hz} to {15 kHz}} The standard conditions are defined by {numerical expression of practical practical range in the actual desktop use state}.
Also,
{{Specific song Z} is played by {{terminal H} {volume V}}, and {{hi-hat} and {pitch component of the lowest bass}} included in the song are clearly heard, {bass And vocals and hi-hats are well balanced}
A standard condition is defined by {a sensual expression easy to understand for general users}.

The terms defined in the claims are the same in the following description.

The sound reproduction system includes many functions and processes such as {converting sound into an electric signal, sound quality adjustment, digital encoding, recording, demodulation, signal processing, amplification, and converting an electric signal into sound}. {Sound quality of recorded music and speech} can be defined as {work} or {content}, for better or worse, respectively. The {recording, demodulation, amplification} function is much more accurate in terms of sound quality than the {signal processing, converting electrical signals into sound} function, and the inherent sound quality is not a problem.

In general, {signal processing} in the reproduction system has {the {function for correcting the inherent sound quality characteristic}} of the {{converting electrical signal into sound} portion}. When trying to reproduce bass with a small speaker, {signal processing technology for maximizing the ability of the speaker} is difficult, and signal processing must be costly.

In the field of small speakers, recently, products that can reproduce ultra-low sounds even with small speakers with a 1.5-inch diameter have begun to be marketed, but there are significant barriers to their spread. Due to the complexity of the vibration mechanism inside the speaker, advanced signal processing is required to extract the potential of this type of speaker. Of course, signal processing is costly. Furthermore, there is a long-standing track record of {it is difficult to persuade the added value of sound quality in the market}, and {persons in the position of planning sound equipment} have a strong tendency to hesitate to {this kind of product planning} .

In the field of mobile acoustic devices, environmental noise reaches as much as {86 dB} in subways and aircraft.
In normal earphones, the current situation is listening at {volume louder than noise}. As of 2012, inner earphones that powerfully block environmental noise are on the market. In this inner earphone, a sound absorbing material called a sound insulation piece is attached to the opening of the earphone. Under strong environmental noise, {environmental noise transmitted through the earphone main body} is transmitted to the auditory sense even if {noise entering between the earphone and the inner ear} is completely blocked. This sound insulation piece strongly insulates both {environmental noise entering through the earphone} and {music to be heard}. The sound transmission characteristics of the sound insulation piece are more attenuated as the sound becomes higher, and the attenuation must be corrected by some method. In the main class in which a simple filter for correcting treble is provided inside the earphone, the treble attenuation is considerably corrected. However, complete correction cannot be made with only passive elements. Environmental noise is strongly sound-insulated and quiet, but some deterioration of the treble component of the music must be overcome. Since the sound insulation characteristic of the sound insulation piece is good, a high level of signal processing is also necessary here in order to obtain a good reproduction sound.

There are the following first, second, third and fourth problems.
The first issue is
At present, the user cannot change the sound quality even if the user purchases an acoustic product. Most users cannot use general-purpose sound quality adjustment functions.

The second problem is that the sound quality determined by the manufacturer that supplies the sound product is not necessarily {{optimum sound quality} or {sound quality that makes the best use of resources}}. In most cases, the signal processing that can be used is low-function because the required cost is low.

The third issue is
The sound insulation piece attached to the inner earphone not only reduces the environmental noise that reaches the ear, but also greatly blocks the {reproduced sound of the earphone} to be heard. The sound insulation characteristics vary greatly depending on the product type.

The fourth issue is
Many sound reproduction apparatuses are provided with a sound quality adjustment function, but at present, {{function for adjusting to standard sound quality} and {adjustment of sound quality by preference}} are mixed. Many users do not have basic knowledge or experience of sound quality adjustment, so in most cases they use the sound device {adjustably] or {without adjustment}.

The present invention is
{Independent of one function of {sound quality finishing of sound reproduction products}, {signal processing function of {converting to an electric sound signal}} {incorporate into the terminal having the player function},
{Method for distributing the method as a product},
{One of the methods for adjusting the preferred sound quality in the signal processing built into the terminal}
About.

{Sound quality correction function of {inherent acoustic characteristics} or {incompletely finished sound quality} possessed by a specific sound product on the market} Built-in to correct sound quality. The terminal has an advanced signal processing environment.

For example, when using a commercially available {inner earphone with a specific sound insulation piece} to listen to music by playing it on your smartphone, the {inner earphone with sound insulation piece} on the player's smartphone side has The characteristic property} is corrected.

The purpose of the present invention is
Instead of entrusting {the main role of sound quality expression of the sound reproduction system} to the sound set manufacturer, the function of sound quality expression is opened to the market, and the demand and supply of {product of sound quality expression} are entrusted to the free market. The essence of the present invention is not a {general sound quality expression function} but a {specific sound quality expression function}.

By exposing {sound quality expression function} of individual products to free market competition, {sound quality that is an important factor of sound products} is selected by the user's intention. Since the product of {sound quality correction function} is an application program, it is easy to improve, and it is possible to supply various signal processing functions with a very low entry barrier, low cost and high performance.
And for that,
{Procedure for providing a certain standard for sound quality reproduced by various sound reproduction systems} and {Method for easily implementing the method}.

There are the following first to eighth effects.

First, in order to make {optimal sound quality expression} in {{the person who is involved in the design of the essential {sound quality reproduction ability and sound quality reproduction performance}}} and {{given the reproduction environment}, which are related to sound quality. The division of labor with those who are responsible for the design of sound quality corrections} has been established, creating a place for free competition in the evaluation of sound quality in each field.

Second,
First, by distributing the sound quality expression function as a product in the free market, it is possible to create a place where an inexpensive and sophisticated sound quality expression function appears in the market.
The sound quality of the sound device fixed in {the mass production and mass market environment} can be improved by extremely high quality signal processing {without any changes to the product}. Furthermore, {sound quality supply side {by concept or method}}, {{supply of various sound quality expression technologies} and {demand for various sound quality expression}} are cultivated.

Third,
The {business model with this sound quality expression function as a product} features {no need to change any of the current audio devices} and enables the entry of new IT businesses.
{Little capital} and {{sound quality}, {sound propagation} and {vibration} {knowledge and experience}} and {sensitivity} offer the possibility of starting a global business at {individual level} To do.

Fourth,
Different {various sound qualities} can be standardized depending on the product.

Fifth,
By making the tuning function to the standard sound quality and the tuning function to the user's preference sound quality independent, the sound quality adjustment by the user's sound preference becomes easier to understand.

Sixth,
Audio equipment manufacturers can design products with the emphasis on {essential {sound quality reproduction capability and sound quality reproduction performance} range} without being particular about color, regarding the theme of sound quality tuning of audio equipment to be sold. .

Seventh,
Needless to say, the sound product supply side can provide the sound quality expression function claimed from the standpoint of supplying the sound product, as before. Alternatively, by providing a {sound quality correction function Ghm} for a specific terminal device based on a plurality of types of concepts for a specific acoustic product M}, it is possible to satisfy a wide range of market demands.

Eighth,
When a product manufacturer has to change the sound quality of a product for some reason after shipping the acoustic product to the market, it can be easily handled in the form of {change at the application program level}.

Explanatory drawing of {{how to use}, {distribution as a product}, {relationship with user}, {method of incorporating into terminal}} of the present invention. Explanatory drawing of the {preference sound quality adjustment function} of Claim 3 of this invention. FIG. 2A is a two-dimensional coordinate diagram displayed on a terminal for preference sound quality adjustment. FIG. 2B is an explanatory diagram of the function of the horizontal axis coordinate. FIG. 2C is an explanatory diagram of the function of the vertical coordinate.

In order to measure the {sound quality characteristic m} {Rm} of a specific acoustic device M and correct it to the intended sound quality,
{Sound quality correction characteristic m} {1 / Rm} is obtained. In general, the {sound quality correction characteristic m} is the {reciprocal or approximate value thereof} {1 / Rm} of the original {sound quality characteristic m}. A {preferred sound quality adjustment function E} that allows the user to adjust the sound quality to a preference is prepared.
A program {signal processing function Ghm} is built in which {{sound quality correction characteristic m} and {sound quality adjustment function E}} are incorporated into {terminal unit H}. The {signal processing function Ghm} is supplied to the general user as {application software Ahm} of {the sound quality correction characteristic for correcting the {characteristic specific to the acoustic apparatus M}} operating on the {{terminal device H}}. Is done.

A user accesses {server Shm} by some means to download {application software Ahm}, and incorporates {signal processing function Ghm} into {terminal H} of the user.
{H} means the type of {terminal H}, and {m} means the type of {audio device M}.
A typical example of a user {terminal device H} is {a mobile multi-function communication terminal called a smart phone, a mobile computer, a laptop computer, a mobile phone}. {Each terminal device has a different program structure depending on the type of OS to be used and the manufacturer to be manufactured}, so even {Gm} of the same signal processing must be a program specialized for the terminal device.
A typical example of the user {acoustic device M} is {passive type noise reduction earphone, sound insulation piece for the earphone, general earphone, desktop speaker system, high performance small speaker system}, and the like. Since each {acoustic device M} has its own characteristic {Rm}, {by applying an inverse characteristic {1 / Rm} for correcting the {unique characteristic}}, Cancel {inherent characteristics}.

The following is a description with reference to the drawings.
FIG. 1 is an explanatory diagram of {{how to use}, {distribution as a product}, {relationship with users}} of the present invention.
{Q} is a user, {H} is a terminal operated by {user Q}, {M} is an acoustic device operated by {user Q}, {Shm} is a server of {application software Ahm}, and {Ahm} is Application software for {terminal H} and {acoustic apparatus M} having {signal processing function Ghm}.
{Ghm} is a signal processing function for {terminal H} and {acoustic device M},
{{Sound quality correction function m}} having a characteristic {{1 / Rm}} and {Sound quality adjustment function E}.
{F} is an input signal of the {preferred sound quality adjustment function E}, and {F} is an output signal thereof.
{Uq} is the playback sound quality heard by {user Q}.
{Internet} is the Internet environment.
{Source} is an input acoustic signal of {Ghm}.
{Control} includes {{sound quality correction function m} and {preferred sound quality adjustment function E}} of {application software Ahm} built into {terminal H}, and {display and operation} of {{terminal H}} } Is a control program of a part related to.

When {User Q} plays the music played by {Terminal H} on {Sound Device M}, {Application Software Ahm} is installed in the Internet environment for the purpose of improving the sound quality played by {Sound Device M}. Via {server Shm}. In this case, {Application Software Ahm} may be downloaded directly to {Terminal H}, or may be indirectly downloaded to {Device H}, which is indirectly downloaded to another device. There are some cases.
The {sound quality correction function m} and the {preferred sound quality adjustment function E} included in the {application software Ahm} are incorporated in the reproduction system of the {terminal H}. As a result, the reproduction signal output from {terminal H} is subjected to the characteristic {1 / Rm} of {sound quality correction function m} and the characteristic {Eq} selected by {user Q} of {preferred sound quality adjustment function E}. Signal.
As a result, {playback sound quality Uq} selected by {user Q} is
{1 / Rm} * {Eq} * {Rm}.

FIG. 2 is an explanatory diagram of the {preferred sound quality adjustment function E} of claim 4 of the present invention.
FIG. 2 (a) is a two-dimensional coordinate diagram displayed on a terminal for preference sound quality adjustment.
The preference sound quality is determined by selecting one point {x, y} of two-dimensional coordinates.
FIG. 2B is a functional explanatory diagram in the horizontal axis direction. The horizontal axis determines {ratio of bass component to high temperature component}. The treble component decreases as the position of {x} moves to the left. The bass component decreases as the position of {x} moves to the right. The movement from the leftmost end to the rightmost end changes from a sound quality with the least amount of high sound components to a sound quality with the least amount of low sound components.
FIG. 2C is a function explanatory diagram in the vertical axis direction. The vertical axis is {the ratio of the treble component and the bass component} determined on the horizontal axis}}, and determines the ratio of {the synthesized component of the treble component and the bass component} to the original music. When the position of {y} moves up, the sound quality becomes sharp and powerful. When the position of {y} moves down, the sound quality becomes natural. Since the horizontal axis determines the balance between bass and treble, and the vertical axis determines the sharpness, the relationship between the coordinate positions and {impression of the general listener's sound quality} correspond in an image, and the selection of sound quality is convenient. . Various parameters are selected so that the center position {Xc, Yc} of the coordinates balances the appropriate sharpness and naturalness.
The mechanism is
As shown in claim 3 ,
{F} is the output signal of {preference sound quality adjustment function E}
{F} + {Ke} * {{Kb * {Bass_f} + {Kt} * {Treble_f}}}
It is expressed by Since the specific method of extracting the low tone component and the high tone component is not the essence of the present invention, the description thereof will be omitted.
The following is a specific example of the preference sound adjustment function, which is extremely simple and effective.
{Bass_f} is {30 times the quadratic integral value of {f},
{Treble_f} is {15 times the second derivative of {f},
{Ke} is {0.33},
For {Kb} and {Kt}, the selection of both {1} is the coordinate center position {Xc, Yc}.

The following are the main points of each claim.
Claim 1 is the most general method of the present invention. The essence of { Claim 1, Claim 2 and Claim 3} is {incorporating a signal processing function for sound quality correction into a terminal}. {Specific procedure of signal processing itself for realization} is not essential.

Claim 2 is a general method of {when the acoustic device defined in claim 1 is intended for an inner earphone having a sound insulation piece}.

Claim 3 is a general method for {selecting the preferred sound quality by the user of the preferred sound quality adjustment function defined in claim 1 and claim 2} {when corresponding to a point on a two-dimensional coordinate}. .

M Specific sound device or sound device belonging to a specific group__
R Inherent sound quality characteristics of sound equipment
Rm {Inherent sound quality characteristic of acoustic device M} 1 / Rm {Rm} * {1 / Rm} is practically {1}
E Preference sound quality adjustment function
Q Specific user
Eq Specific sound quality characteristics adjusted by {user Q}
H Specific terminal
Uq Playback quality adjusted by user
Gm {Signal processing function having {sound quality adjustment function E} and {sound quality correction characteristic m}}
Ghm {Incorporate into terminal H} {Gm}
Application software for {terminal H} with Ahm Gm
Shm Ahm's server * Multiplication operator + Addition operator
f Input signal of {sound quality adjustment function E}
F {Sound quality adjustment function E} output signal
Bass_f {Low frequency component of the input signal f}
Treble_f {High-frequency component of {input signal f}}
Kb {Bass_f} component coefficient
Kt {Treble_f} component coefficients
Ke {Kb * {Bass_f} + Kt {Treble_f}} coefficient of component
X Preferences sound quality setting coordinate horizontal axis
Y preference sound quality setting coordinate vertical axis
x X axis coordinate
y Y-axis coordinate {x, y} Point whose X-axis coordinate is {x} and Y-axis coordinate is {y}
Xc Horizontal axis origin
Yc Vertical axis origin
Xleft Left end of horizontal axis
Xright Right end of horizontal axis
Ytop Top of vertical axis
Ybottom Bottom of vertical axis

Claims (3)

A device that demodulates the recorded acoustic signal into an electrical acoustic signal is a terminal,
A device that converts the electroacoustic signal demodulated by the terminal into sound is an acoustic device ,
{Specific audio device M} is set as {Audio device M},
The sound quality reproduction characteristic of {acoustic device M} is {Rm},
{Multiply {Rm} by {1 / Rm} and the result is about {1} from a practical point of view}
{1 / Rm} satisfying the above is set as {sound quality correction characteristic m},
The function for creating {sound quality correction characteristic m} is {sound quality correction function M},
In order to adjust the playback sound quality of the audio device to the user's preference, the function that the user can adjust is the {preference sound quality adjustment function E},
When a specific {user Q} listens to a reproduction sound by a combination of the {acoustic device M} and the {sound quality correction function M}, the characteristic of the {preferred sound quality adjustment function E} adjusted by the preference of {user Q} is { Eq}
{Eq} is set as {preference sound quality characteristic q}
The specific terminal used by {user Q} is {terminal H},
The sound quality reproduction characteristic when {user Q} reproduces the output signal of {terminal H} by a combination of {audio device M} , {sound quality correction function M}, and {preferred sound quality adjustment function E} is {Uq}. ,
Where the universal nature of the acoustic system,
{{Uq} equals {{Eq} * {1 / Rm} * {Rm}}}
Applying the physical properties
{ Signal processing function Gm} is a signal processing function that combines {preference sound quality adjustment function E} and {sound quality correction function M} .
{{Signal processing function Gm}} that functions by being incorporated in {Terminal H} is {Signal processing function Ghm},
Software that realizes {signal processing function Ghm} is {application software Ahm},
The function to supply {application software Ahm} to the market via the Internet environment is {server Shm},
{Application software Ahm} can be downloaded from {Server Shm} to {Terminal H} via the Internet environment by any means,
By starting {application software Ahm} on {terminal H}, the output of the reproduction function inside {terminal H} functions as input of {signal processing function Ghm}, and {terminal H} becomes {terminal When the acoustic signal output to the outside of H} is reproduced by {acoustic product M},
The sound quality reproduction characteristic {Uq}
Depends on the product of {sound quality reproduction characteristic Rm}, {sound quality correction characteristic m}, and {preferred sound quality adjustment characteristic Eq} ,
{Terminal H}
{Reverse characteristics {1 / Rm}} for canceling the characteristic {Rm} inherent in {acoustic apparatus M} that reproduces the output signal of {terminal H} is multiplied by the reproduction signal in advance to obtain the standard sound quality. Adjust {sound quality correction function m}}
as well as,
{By using the signal obtained by multiplying the reproduction signal multiplied by the inverse characteristic by the preference sound quality characteristic {Eq} selected by the user as the input of {acoustic apparatus M}, {acoustic apparatus M} Application software for realizing a {preferred sound quality adjustment function E}} that tunes the reproduced sound quality to the user's preferred sound quality.
When listening to music with an inner earphone in a large amount of environmental noise, {{sound insulation piece with a sound insulation function that significantly reduces environmental noise {attachment attached to the sound emission port of the inner earphone}} is {sound insulation piece}
In the role of {sound insulation piece} to reduce environmental noise, {insulates environmental noise passing through the inner earphone itself} and {insulates the reproduced sound signal} simultaneously with {sound insulation effect through the earphone body},
The reproduction characteristic of the inner earphone deteriorated by the {earphone body passage sound insulation effect} is {sound insulation piece transmission characteristic},
{By inner earphone and sound insulation piece} The reproduction characteristic is {Transmission characteristic of inner earphone with sound insulation piece},
{{Specific sound insulation piece} or {{set of specific inner earphone} and {specific sound insulation piece}}} as {acoustic device M},
The sound quality reproduction characteristic of {acoustic device M} is {Rm},
{Multiply {Rm} by {1 / Rm} and the result is about {1} from a practical point of view}
{1 / Rm} satisfying the above is set as {sound quality correction characteristic m},
The function for creating {sound quality correction characteristic m} is {sound quality correction function M},
In order to adjust the playback sound quality of the audio device to the user's preference, the function that the user can adjust is the {preference sound quality adjustment function E},
When a specific {user Q} listens to a reproduction sound by a combination of the {acoustic device M} and the {sound quality correction function M}, the characteristic of the {preferred sound quality adjustment function E} adjusted by the preference of {user Q} is { Eq}
{Eq} is set as {preference sound quality characteristic q},
The specific terminal used by {user Q} is {terminal H},
When {user Q} reproduces the reproduction signal of {terminal H} by a combination of {audio device M} , {sound quality correction function M}, and {preferred sound quality adjustment function E}, the reproduction sound quality characteristic is {Uq}. ,
Where the universal nature of the acoustic system,
{{Uq} equals {{Eq} * {1 / Rm} * {Rm}}}
Applying the physical properties
{ Gm} is a signal processing function that combines the {preference sound quality adjustment function E} and the {sound quality correction function M} ,
{{Signal processing function Gm}} that functions by being incorporated in {Terminal H} is {Signal processing function Ghm},
Software that realizes {signal processing function Ghm} is {application software Ahm},
The function to supply {application software Ahm} to the market via the Internet environment is {server Shm},
{Application software Ahm} can be downloaded from {Server Shm} to {Terminal H} via the Internet environment by any means,
By starting {application software Ahm} on {terminal H}, the output of the reproduction function inside {terminal H} functions as input of {signal processing function Ghm}, and {terminal H} becomes {terminal When the acoustic signal output to the outside of H} is reproduced by {acoustic product M},
The sound quality reproduction characteristic {Uq}
Depends on the product of {sound quality reproduction characteristic Rm}, {sound quality correction characteristic m}, and {preferred sound quality adjustment characteristic Eq} ,
{Terminal H}
{Reverse characteristics {1 / Rm}} for canceling the characteristic {Rm} inherent in {acoustic apparatus M} that reproduces the output signal of {terminal H} is multiplied by the reproduction signal in advance to obtain the standard sound quality. Adjust {sound quality correction function m}}
as well as,
{By using the signal obtained by multiplying the reproduction signal multiplied by the inverse characteristic by the preference sound quality characteristic {Eq} selected by the user as the input of {acoustic apparatus M}, {acoustic apparatus M} Application software for realizing a {preferred sound quality adjustment function E}} that tunes the reproduced sound quality to the user's preferred sound quality. {Taste sound quality adjustment function E}, {terminal H}, {application software Ahm}, and characteristic {Eq} are the same as defined in claims 1 and 2,
Let {x, y} be a position expressed in two-dimensional coordinates,
The horizontal axis of the coordinate axis is {X}, the vertical axis is {Y},
The origin of the X axis is {Xc}, the origin of the Y axis is {Yc}
The left end of the X axis is {Xleft}, the right end of the X axis is {Xright}
The lower end of the Y axis is {Ybottom}, the upper end of the Y axis is {Ytop},
Let {Ke} be the overall sound quality adjustment factor,
Let {Kt} be the maximum value of {high-frequency component enhancement coefficient},
{Kb} is the maximum value of {bass component enhancement coefficient},
When {y} changes from {{Ybottom} to {Ytop}}, {Ke} changes from {0 to 1} corresponding to {Y}
{Yc} is in the middle of the vertical axis,
{Ke} is a specific value between {0.1} and {0.9} with {{0.31} as an example {Kec},
When {Y} changes from {Ybottom} to {Yc}, {Ke} shall change from {0} to {Kec}
When {Y} changes from {Yc} to {Ytop}, {Ke} shall change from {Kec}} to {1}
{Xc} is at the center of the horizontal axis,
When {{x} changes from {{Xc} to {Xleft}}, {Kb} is a constant value {1} and {Kt} changes from {1} to {0}
When {{x} changes from {{Xc} to {Xright}}, {Kt} is a constant value {1} and {Kb} changes from {1} to {0}
Let {f} be the input signal of the {preference sound quality adjustment function E},
The specific bass component of the acoustic input signal {f} is {Bass_f}
The specific treble component of the acoustic input signal {f} is {Treble_f}
{F} is the output signal of the {preferred sound quality adjustment function E},
{F}
{F} + {Ke} * {{Kb * {Bass_f} + {Kt} * {Treble_f}}}
The characteristic {Eq}} of the {preferred sound quality adjustment function E} corresponding to the { coordinate {x, y} is expressed by three parameters {Ke}, {Kb}, and {Kt}. Shall be
The display device of {terminal H} defined in claim 1 and claim 2
Display plane coordinates with a range of {X} and a range of {Y},
The {display unit {}, {displays a point {x, y}} on the plane coordinates, which is selected by the person operating the {terminal unit H},
{Terminal H} in order to {determine the characteristic {Eq} of the preference sound quality adjustment function E} by operating and selecting the coordinates {x, y} via the coordinates displayed on the {terminal H} The application software according to claim 1 or 2, which includes application software for realizing a function of controlling the display function of the above.