KR100703923B1 - Stereo sound optimization device and method for multimedia equipment - Google Patents

Abstract

The stereoscopic sound optimization device for a multimedia device of the present invention analyzes a frequency spectrum of an audio file to be reproduced and generates a harmonic component of the corresponding frequency, thereby generating a low frequency harmonic component for generating a low frequency sound for a frequency component below a predetermined low cutoff frequency. And restore a high frequency harmonic component for generating a high frequency sound for a frequency component above a predetermined high frequency cutoff frequency, and set the level of the generated low frequency harmonic component and the high frequency harmonic component by a user. And a stereo sound processor unit for controlling the high frequency sound using a level setting value and then mixing and outputting the high frequency sound with a mid frequency component. To play a fixed level midrange reference sound and the low / high frequency reference sound according to the level being increased or decreased, and to set the level of the currently played low / high frequency reference sound to the level of the low frequency sound / high frequency sound. A harmonic component level adjusting unit for providing a corresponding reference sound level as a level setting value to the stereophonic sound processor unit when a user inputs the same; It consists of technical features.

Description

3D Sound Optimizing Apparatus and Method for Multimedia Devices}

1 shows small acoustic transducers,

Figure 2 is an embodiment showing the configuration of a multimedia device having a stereophonic sound optimization device of the present invention,

3 is a block diagram of a stereophonic sound processor of the stereophonic sound optimizer according to an embodiment of the present invention;

Figure 4 is a block diagram of the harmonic component level control unit of the stereoscopic sound optimization device according to an embodiment of the present invention,

Figure 5 is an embodiment of the user menu showing the harmonic component level adjustment operation state of the stereoscopic sound optimizer according to an embodiment of the present invention,

6 is a flowchart sequentially showing a harmonic component level adjusting process of a stereophonic sound optimization method according to an embodiment of the present invention;

7 is a flowchart sequentially showing a stereophonic sound reproduction process of the stereophonic sound optimization method according to an embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

100: multimedia equipment

110: key input unit

120: display unit

130: memory

140: sound transducer

200: 3D Sound Optimizer

210: stereo sound processor

211: decoder unit

212: DA conversion unit

213: spectrum analysis unit

214: low frequency extension

215: high frequency expansion unit

216 mixing portion

220: harmonic component level control unit

221: control unit

222: menu display unit

A: adjustment target display unit

B: level display

223: mid-frequency reference tone output unit

224: low frequency reference tone output unit

225: high frequency reference tone output unit

226 level increase and decrease

227: reference sound playback unit

228: level setting value storage unit

The present invention relates to an apparatus and method for optimizing stereo sound for a multimedia device, and more particularly, psychoacoustics effects of low and high frequency sounds lost during sound reproduction through a small acoustic transducer in a portable multimedia device. In a multimedia device that reproduces stereophonic sound by restoring the signal, a low frequency reference sound and a high frequency reference sound are generated using the harmonic components of the low / high frequency reference noise signal, and the midrange reference sound, which is a midrange noise signal sound, is generated. This allows the user to adjust the level subjectively so that the user can adjust the level so that the level of the low frequency sound and the high frequency sound restored when the sound is reproduced in the multimedia device can be adjusted to the setting value by the subjective control of the user. Stereo sound in multimedia equipment Perfume optimization apparatus and method.

Recently, various types of portable multimedia devices have been used due to the development of information and communication technology, and most of the sound reproduction in the portable multimedia devices is a portable small sound converter such as earphones, headphones, a clip phone, a kernel phone as shown in FIG. Is done through. These small acoustic transducers have a large difference in acoustic characteristics reproduced according to their types, and also show large differences in acoustic characteristics among manufacturers of the same type of products.

The purpose of stereophonic sound reproduction in multimedia equipment is to make the reproduction sound characteristics heard through the small sound transducer similar to the sound characteristics intended by the sound engineer in the recording studio. The sound engineer listens to in the recording room by means of a full-range loudspeaker that reproduces all 20 Hz to 20 kHz sound, which is audible to humans, located at 30 degrees left and right. The sound emitted by the sound is reflected on the wall of the recording studio where the diffuser is attached before reaching the sound engineer's ear, and the sound is reached with various reflections, which forms a stage between both loudspeakers in front of the sound engineer. Placed in the right position between the loudspeakers, you will feel as if the sound is being reproduced at the venue.

However, when using a small transducer, most of the notes to be played in front of the listener are either on the ears of the listener or on both ears because the transducer is inserted into both ears of the listener, or the sound is played while the transducer is pressing on the listener's ear. It is confined to the listener, causing frustration to the listeners.In comparison with the general loudspeakers, earphones and headphones have a smaller diaphragm, which limits the reproduction of low-frequency sounds. Many of the frequency tones are lost in the compression process.

In particular, due to the miniaturization of the portable acoustic transducer, earphones rapidly reduce low frequency reproduction from 100 Hz or less. The easiest way to solve the limitation of low frequency reproduction ability is to use an equalizer to increase the frequency level below 100 Hz. will be. However, this simple frequency level increase causes excessive movement of the acoustic diaphragm of the small acoustic transducer, greatly reducing its durability, increasing power consumption due to excessive movement of the acoustic diaphragm, and increasing the dynamic frequency of the entire band due to the low frequency level increase. Narrower dynamic range limits dynamic musical expression and increases the likelihood of introducing clipping noise due to excessive movement of the small transducer at low frequencies.

Therefore, in order to solve these problems, the front sound image positioning algorithm, the low frequency band expansion algorithm, and the high frequency band, which are mounted in the form of hardware or software inside the multimedia device, allow the listeners to listen similarly to the ideal sound reproduction environment. Various stereophonic reproduction algorithms such as extension algorithms are used.

The above-mentioned frontal topological algorithm, low frequency band expansion algorithm, and high frequency band expansion algorithm are essential elements for stereophonic sound reproduction of multimedia equipment. Among them, in the case of frontal topological algorithm centered on reverberation sound, Although the change is not large, in the case of the low frequency band widening algorithm and the high frequency band widening algorithm using the harmonic component, the stereophonic effect is greatly influenced by each algorithm level value. .

In order to solve this problem, users can compose menus to adjust the level values of the low frequency band extension algorithm and the high frequency band extension algorithm while listening to music on the multimedia device. Is difficult, not only can not accurately sense or confirm whether or not properly adjusted through the music, there is a problem that the operation is cumbersome and time-consuming.

Therefore, the present invention is to solve the above-mentioned disadvantages and problems of the prior art, psychoacoustic sound of the low frequency and high frequency sound lost during the reproduction of the multimedia device, in particular through a portable multimedia device using a small sound transducer In a multimedia device that reproduces stereoscopic sound by restoring using a mathematical principle, the low frequency and high frequency reference tones are generated using the harmonics of the low frequency and high frequency reference noise signals, and the generated low frequency and high frequency reference tones By listening to the mid-frequency reference sound, which is the mid-frequency noise signal, the user can easily listen to the low-frequency reference sound and the mid-frequency reference sound or the high-frequency reference sound and the mid-frequency reference sound. Can be set on a subjective basis And a stereophonic sound optimization device and method for reproducing an optimal stereophonic sound by reproducing low and high frequency sounds restored during sound reproduction in a multimedia device according to a level value set by a user. It is an object of the present invention to provide.

The above object of the present invention is a device for reproducing an optimal stereophonic sound in a multimedia device for reproducing sound through an acoustic transducer, by analyzing a frequency spectrum of an audio file to be reproduced and generating a harmonic component for a corresponding frequency. Restores a low frequency harmonic component for generating a low frequency sound for a frequency component less than a wave number and a high frequency harmonic component for generating a high frequency sound for a frequency component above a predetermined high frequency cutoff frequency; A stereophonic sound processor which adjusts the level of the frequency overtone component by using the level setting value of the low frequency sound set by the user and the level setting value of the high frequency sound, and then mixes and outputs the mid frequency component; To play a fixed level midrange reference sound and the low / high frequency reference sound according to the level being increased or decreased, and to set the level of the currently played low / high frequency reference sound to the level of the low frequency sound / high frequency sound. A harmonic component level adjusting unit for providing a corresponding reference sound level as a level setting value to the stereophonic sound processor unit when a user inputs the same; It is achieved by a stereophonic sound optimization device of a multimedia device including a.

In addition, the above object of the present invention is a method for reproducing an optimal stereophonic sound in a multimedia device that reproduces sound through an acoustic transducer. Generating a low frequency harmonic component for generating a low frequency sound for a high frequency harmonic component for generating a high frequency sound for a frequency component above a predetermined high frequency cutoff frequency; (B) adjusting and outputting the generated low frequency harmonic components and low frequency harmonic components using a level setting value of a low frequency sound set by a user and a level setting value of a high frequency sound; (C) mixing and outputting the output low frequency harmonic components and high frequency harmonic components with the mid frequency components of the audio file; It is achieved by a stereophonic sound optimization method of a multimedia device.

In addition, the above object of the present invention is a method for reproducing an optimal stereophonic sound in a multimedia device that reproduces sound through an acoustic transducer, and (A'-1) a menu for setting a level value of a high frequency sound by a user. If selected, cross-reproducing the mid-frequency reference sound at a fixed level and the high-frequency reference sound according to the level being increased or decreased; (A'-2) when a user input for storing the level value of the high frequency sound is generated, storing the currently reproduced high frequency reference sound level as a high frequency sound level setting value; It is achieved by a stereophonic sound optimization method of a multimedia device including a.

Details of the above object and technical configuration of the present invention and the resulting effects thereof will be more clearly understood from the following detailed description based on the accompanying drawings.

First, Figure 2 is an embodiment showing the configuration of a multimedia device having a stereophonic sound optimization device of the present invention.

As shown, the stereoscopic sound optimizer 200 of the present invention is an earphone in a multimedia device 100 having a key input unit 110, a display unit 120, a memory 130, and an acoustic transducer 140. When the audio file is reproduced through the small acoustic transducer 140, the multimedia device 100 is mounted on the multimedia apparatus 100 in the form of hardware or software for optimal stereoscopic sound reproduction.

The stereophonic sound optimization device 200 of the present invention restores the low frequency sound and the high frequency sound by using the harmonic component, and the low frequency harmonic component in which the user sets the level of the low frequency sound and the high frequency sound to be restored. The stereo sound processor 210 outputs after adjusting the level setting value of the component, and the level setting value of the high frequency harmonic component component, and the harmonic component level adjusting unit 220 for user setting of the level setting value. Include.

When the audio is reproduced through the small acoustic transducer 140, a reproduction sound corresponding to a frequency component below a specific low frequency cutoff frequency is hardly heard, and according to the present invention, the harmonic components of low frequency components that are hard to be heard through the small acoustic transducer are blocked. It is generated for all frequency bands above the frequency, and the psychoacoustic effect gives the user the illusion of hearing low frequency components.

Here, the sound produced by the harmonic component of the low frequency component is referred to as low frequency sound in the present invention. That is, the low frequency sound refers to the sum of the harmonic components for the frequency components below the low cutoff frequency. When the small acoustic transducer 140 does not reproduce well below 100 Hz, the low cutoff frequency is 100 Hz.

In addition, an audio file played in a multimedia apparatus is generally a compressed file, and components of a high frequency cutoff frequency or more are lost during the compression process. Restoration is made by generating harmonics.

Here, in the present invention, a sound for a frequency component equal to or greater than the high frequency cutoff frequency restored using the frequency component of the mid frequency band is referred to as a high frequency sound. And, if a frequency component of 16 kHz or more is lost from the audio file during compression, the high cutoff frequency means 16 kHz.

In addition, the mid-range sound refers to the sound for the frequency component that can be reproduced through the multimedia device. The multimedia device has a limitation in the reproduction of sound for the component below 100 Hz, and the compressed audio file loses the frequency component over 16 kHz. In the case of one file, the frequency band of the midrange frequency sound may be, for example, about 100 Hz to about 16 kHz.

In the present invention, the stereo sound processor 210 serves to restore the lost low / high frequency sound by generating a harmonic component.

And, if the menu for the harmonic component level adjustment is driven by the user, the harmonic component level control unit 220 alternately reproduces the low frequency reference sound and the mid-frequency reference sound for the level adjustment of the low frequency sound, high frequency By alternately playing the high frequency reference sound and the mid frequency reference sound to adjust the sound level, the user can perform the subjective level adjustment by comparing and listening to the mid frequency reference sound and the low / high frequency reference sound.

In this case, since the low frequency reference sound is for adjusting the level of the low frequency sound, it is preferable to set the sound generated by the same process as the generation of the low frequency sound, and accordingly, the harmonic component level control unit 220 A low frequency reference sound is produced by generating the harmonic component sound of an octave band noise signal having a specific frequency below the low cutoff frequency as a center frequency (for example, 60 Hz). An octave band refers to a frequency band in which the highest frequency of the octave band is twice the lowest frequency.

Similarly, since the high frequency reference sound is preferably a sound generated by the same process as the generation process of the high frequency sound, the harmonic component level control unit 220 in order to produce a component above the high frequency cutoff frequency by generating the harmonic sound. The high frequency reference sound is generated by generating the harmonic component of the octave band noise signal having a specific frequency of the mid frequency band as the center frequency (for example, 8 kHz).

In addition, since the midrange frequency sound reproduced in the multimedia apparatus is a sound of a frequency band reproducible in the original audio file, a separate harmonic component generation process is not required, and thus the midrange frequency reference sound is a specific frequency of the midrange frequency band. This is the octave band noise signal itself with the center frequency (eg 1 kHz).

On the other hand, the harmonic component level adjusting unit 220 adjusts the level of the low / high frequency reference sound that is cross-reproduced with the fixed level mid-frequency reference sound as the user inputs a button for adjusting the level value up / down. It can be played by adjusting, or by changing the level of the low / high frequency reference sound step by step at a predetermined time interval without a user's button input. In the former case, the user may set the final level value by performing the button input for setting when the low / high frequency reference sound judged that the level is appropriate during the button input for adjusting the level is played. As the level is automatically adjusted, it is possible to simply set the level value by finally performing selection button input at a specific level.

Next, each configuration of the stereo sound processor 210 and the harmonic component level control unit 220 will be described in more detail with reference to FIGS.

First, FIG. 3 is a configuration diagram of a stereophonic sound processor unit of a stereophonic sound optimization device according to an embodiment of the present invention.

The stereo sound processor 210 analyzes the frequency spectrum of the audio file to be reproduced to generate a harmonic component of the corresponding frequency component so that the low frequency sound and the high frequency sound are restored, and the generated low frequency harmonic and high frequency harmonic components After adjusting the level of the user, it is responsible for mixing and outputting the mid-frequency components, for this purpose, the decoder unit 211, DA converter 212, spectrum analyzer 213, low-frequency expansion unit 214 ), A high frequency expansion unit 215, and a mixing unit 216.

The decoder 211 decompresses the compressed audio file and inputs it to the DA converter 212, and the DA converter 212 converts the audio bitstream to be reproduced into an analog signal. In the multimedia apparatus 100, it is common to play a compressed audio file. However, if the uncompressed audio file is played, the configuration of the decoder unit 211 may be omitted, and the high frequency sound is a sound lost in the compression process. In this case, the configuration of the high frequency extension unit 215 for restoring the high frequency sound may also be omitted.

Next, the spectrum analyzer 213 analyzes the spectrum of the converted analog signal and outputs frequency components of the audio bitstream. Here, the outputting of the frequency component is such that the low frequency expansion unit 214 and the high frequency expansion unit 215 can restore the low frequency sound and the high frequency sound by analyzing the output frequency component. The output frequency component includes a low frequency component below a cutoff frequency that is not easily reproduced by a small acoustic transducer, and a harmonic component for the high frequency component lost in a digital audio compression process. This allows the generation of low and high frequency sounds.

The low frequency extension unit 214 is a low frequency component analysis unit 214-1 for extracting low frequency components which are components below the low cutoff frequency of the multimedia device from the spectrum analysis result, and the harmonic components of the extracted components of the multimedia device. The low frequency harmonic component generator 214-2 for generating a low frequency harmonic component, which is the harmonic component included in the mid frequency band, that is, the audible band (eg, 100 Hz to 16 kHz). And a low frequency harmonic component level adjusting unit 214-3 for adjusting and outputting the low frequency sound level setting value provided from the level adjusting unit 220.

In addition, the high frequency expansion unit 215 is a high frequency component analysis unit 215-1 for detecting a harmonic component for the high frequency component of the high frequency cutoff frequency or more from the spectrum analysis result, and the high frequency harmonic based on the detected harmonic component A high frequency harmonic component generating unit 215-2 for generating a component and a high frequency frequency generated by adjusting the level of the generated high frequency harmonic component to a high frequency sound level setting value provided from the harmonic component level adjusting unit 220 and outputting the high frequency. The harmonic component level adjusting unit 215-3 is included.

As described above, the low frequency harmonic components and the high frequency harmonic components output from the low frequency expansion unit 214 and the high frequency frequency expansion unit 215 are mixed with the mid-frequency components through the mixing unit 216 to convert the sound converter 140. Play through).

Next, Figure 4 is a configuration diagram of the harmonic component level control unit of the stereoscopic sound optimizer according to an embodiment of the present invention, Figure 5 shows the harmonic component level control operation state of the stereoscopic sound optimizer according to an embodiment of the present invention One embodiment of a user menu is also shown.

The harmonic component level control unit 220 allows the user to set the level value of the low / high frequency sound by comparing and listening to the mid frequency reference sound and the low frequency and high frequency reference sound. The reference sound at the time of user input to cross play the sound and the low / high frequency reference sound with increasing / decreasing level, and to set the level of the low / high frequency reference sound currently being reproduced to the level of the low / high frequency sound. It serves to provide a level to the stereophonic sound processor 210 as a level set value, the control unit 221, the menu display unit 222, the mid-frequency reference tone output unit 223 as shown in FIG. The low frequency reference signal sound output unit 224, the high frequency reference signal sound output unit 225, the level increase / decrease unit 226, the reference sound reproducing unit 227, and the level setting value storage unit 228 may be configured.

The control unit 221 controls the level of the low / high frequency reference sound which is reproduced crosswise with the mid-frequency reference sound, and controls the crossover reproduction of the mid-frequency reference sound and the low / high frequency reference sound and displays a user menu such as a user's menu level. It is responsible for the overall operation control of the adjusting unit 220.

As shown in the embodiment of FIG. 5, the menu display unit 222 adjusts the adjustment target display unit A for displaying whether the current level setting target is a low frequency sound or a high frequency sound, and the current reference sound reproducing unit 227. It is responsible for displaying a user menu on the screen including a level display unit (B) for displaying the level value and the level setting range of the low frequency reference sound or high frequency reference sound output through the, the menu configuration of FIG. It is natural that it is only an example and is not limited to the present invention.

In addition, as shown in Figure 5, the level setting value of the low frequency sound and high frequency sound in the present invention may be set to one of the values of -5 to +5, but this is also not limited.

Next, the mid-frequency reference tone output unit 223 generates a mid-frequency reference tone of a fixed reference level, and the low-frequency reference tone output unit 224 outputs a low-frequency reference signal of a fixed level and a high-frequency reference tone. The unit 225 generates a high frequency reference tone of a fixed level. In this case, each of the reference signal sound output units 223, 224, and 225 may simply output a pre-stored sound signal, and may include an oscillator for generating the reference signal sound, respectively.

In addition, the mid-frequency reference tone may be, for example, an octave band noise signal having a center frequency of 1 kHz, which is an audible band intermediate frequency of the multimedia apparatus, and the low-frequency reference tone may be an intermediate frequency among frequencies below the low cutoff frequency. The signal for the harmonic component of an octave band noise signal having a center frequency of 60 Hz, and the high frequency reference signal sound may be a signal for the harmonic component of an octave band noise signal having a center frequency of 8 kHz, which is an intermediate frequency among the frequencies above the high frequency cutoff frequency. Each center frequency is not limited in the present invention because it can be set within an appropriate range.

Meanwhile, since the low frequency reference sound and the high frequency reference sound are reference sounds for adjusting the levels of the low frequency sound and the high frequency sound during stereo sound reproduction, the frequency band extension applied when the low frequency sound and the high frequency sound are generated. It is preferable to use the sound generated by the algorithm.

Accordingly, the low frequency reference signal sound output unit 224 is a low frequency noise signal sound generator 224-1 for generating a low frequency noise signal to generate a low frequency reference sound, and the low frequency band noise signal A low frequency spectrum analyzer 224-2 for analyzing a frequency component of a low frequency reference signal generator 224-3 for generating a harmonic component of the low frequency noise signal in a mid frequency band using the spectrum analysis result. ).

The low frequency noise signal sound generator 224-1 generates an octave band low frequency noise signal having a specific frequency in a low frequency band below the cutoff frequency of the small acoustic transducer as a center frequency, thereby generating a low frequency spectrum analyzer 224-2. ).

The low frequency spectrum analyzer 224-2 analyzes the spectrum of the generated low frequency noise signal, and outputs a frequency component of the low frequency noise signal to the low frequency reference signal tone generator 224-3. The frequency reference signal sound generator 224-3 generates the harmonic component included in the mid frequency band among the harmonic components of the low frequency noise signal by using the low frequency noise signal frequency component and converts the generated harmonic component into the low frequency frequency. Output as reference sound.

The high frequency reference signal sound output unit 225 includes a high frequency noise signal sound generator 225-1, a high frequency spectrum analyzer 225-2, and a high frequency reference signal sound generator 225-3. The high frequency noise signal sound generator 225-1 generates an octave band high frequency noise signal having a specific frequency as a center frequency of the mid frequency band, and the high frequency spectrum analyzer 225-2 generates the high frequency noise. Analyzing the spectrum of the signal, and outputs the frequency components of the high frequency noise signal, the high frequency reference signal sound generator 225-3, using the high frequency noise signal frequency components, the harmonic of the high frequency noise signal The harmonic component included in the lost high frequency band is generated. The harmonic component generated in this way is output as a high frequency reference sound.

As mentioned above, the high frequency noise signal is called a high frequency noise signal because it is a noise signal of the mid frequency band or a signal sound for generating a high frequency reference sound.

Meanwhile, the low frequency spectrum analyzer 224-2 and the low frequency reference signal tone generator 224-3 serve to generate the low frequency reference tone in the same manner as the low frequency tone tone. The frequency spectrum analyzer 225-1 and the high frequency reference tone generator 225-3 also generate the high frequency reference tone in the same manner as the high frequency tone.

Accordingly, the reference signal sound output units 224 and 225 do not include the spectrum analyzers 224-2 and 225-2 and the reference signal sound generators 224-3 and 225-3, respectively. The configuration of the processor unit 210 can be used.

In this case, the low frequency reference beep output unit 224 transmits the low frequency noise signal to the spectrum analyzer 213 of the stereo sound processor 210, and the low frequency noise signal is transmitted to the low frequency component analyzer 214-. 1), the low frequency harmonic component generating unit 214-2 is converted to a low frequency reference signal, and when the converted low frequency reference signal is fed back to the low frequency reference tone output unit 224, the low frequency reference tone is output. The unit 224 may output the low frequency reference signal.

Meanwhile, since the low frequency noise signal includes only a low frequency component, a separate low frequency component analysis may be omitted.

In addition, the high frequency reference signal sound output unit 225 also transmits a high frequency noise signal to the spectrum analyzer 213 of the stereo sound processor 210, and the high frequency noise signal is a high frequency component analyzer. The high frequency reference signal converted through the high frequency frequency harmonic component generator 215-2 and the high frequency reference harmonic component generator 215-2 may be fed back to output the high frequency reference signal.

Next, the level increase / decrease unit 226 is generated from the level of the low frequency reference signal generated from the low frequency reference tone output unit 224 and the high frequency reference tone output 225 under the control of the controller 221. The level of the high frequency reference signal is increased or decreased and transmitted to the reference sound reproducing unit 227.

In this case, the controller 221 may control the level increase / decrease unit 226 to automatically increase or decrease the levels of the low frequency reference signal and the high frequency reference signal by a predetermined time unit. The increase / decrease control command may be transmitted to the level increase / decrease unit 226 according to a hockey input. In this case, the controller 221 may provide each level value directly to the level increase / decrease unit 226 as an increase / decrease control command, and the level increase / decrease unit 226 may adjust the level value up / down according to the increase / decrease control command. You can play or adjust the level to be delivered.

The reference sound reproducing unit 227 is a low frequency reference sound which is a low level reference signal of a predetermined level or a high frequency reference signal which is output from the level increase / decrease unit 226 under the control of the controller 221. Cross-reproduces the mid-frequency reference sound, which is the sound of the fixed mid-range reference signal.For example, the mid-frequency sound of 1 second and the low-frequency sound of 1 second are alternately played at intervals of 1 second. It is possible to set the level, and the high frequency sound of 1 second and the high frequency sound of 1 second are also played back alternately at 1 second intervals, and the level of the high frequency sound can be set. Here, the reproduction length and the reproduction interval of each frequency sound are also not limited in the present invention.

Next, the level setting value storage unit 228 controls the control unit at the time of user input for setting the level of the low / high frequency reference sound currently reproduced by the reference sound reproducing unit 227 to the level of the low / high frequency sound. The reference sound level is stored as a level setting value under the control of 221 and provided to the low frequency extension 214 and the high frequency extension 215 of the stereo sound processor 210.

That is, the controller 221 stores the current level value when there is a button input for setting by the user when the mid-frequency reference sound and the low-frequency / high-frequency reference sound of a specific level cross play. The information stored in the level setting value storage unit 228 is used by the stereo sound processor 210 to adjust the level of the low frequency sound and the high frequency sound.

To this end, the low frequency harmonic component level adjusting unit 214-3 and the high frequency harmonic component level adjusting unit 215-3 of the stereo sound processor 210 directly interwork with the level setting value storage unit 228. Read the level setting value, or request and receive the level setting value from the control unit 221, and receive the level setting value from the control unit 221 in advance and store it in a separate memory. .

In this case, the control unit 221 is a low-frequency (or high-frequency) frequency reference while the low-frequency (or high-frequency) frequency reference sound of a specific level and a fixed level mid-frequency reference sound is cross-reproduced by the reference sound reproducing unit 227 When the user key is input for setting the sound level, the reproduction operation of the reference sound reproducing unit 227 should be stopped and the corresponding level value should be stored.

Next, each process of the stereophonic sound optimization method in the stereoscopic sound optimization apparatus 200 according to the present invention described above will be described in detail with reference to FIGS. 6 and 7 as follows.

First, FIG. 6 is a flowchart sequentially illustrating a harmonic component level adjusting process of the stereophonic sound optimization method, and illustrates an embodiment of the operation of the harmonic component level adjusting unit 220 of the stereophonic sound optimization device 200.

As shown, when the harmonic component level adjustment menu is selected by the user (S301), the harmonic component adjusting unit 220 is a mid-frequency reference sound of a fixed level and a low-frequency reference of a reference level (eg, 0 level). When the sound is cross-reproduced (S303), and there is a user setting button input for setting to the current level (S305), the level of the low frequency reference sound reproduced in step S303 is stored as the level setting value of the low frequency sound ( S309).

In addition, when the setting button is not input while repeating a predetermined number of times, the harmonic component level adjusting unit 220 adjusts the level of the low frequency reference sound by one step to increase or decrease the level (S307) and again. The mid-frequency reference sound of the previous fixed level and the low-frequency reference sound of the level increase and decrease are reproduced (S303).

On the other hand, the present embodiment is an operation process in the case of automatically increasing and decreasing the level without the user input, and as another embodiment after performing step S303, the level of the low frequency reference sound is increased or decreased according to the input for increasing or decreasing the user's level The process (S307) may be performed, or it is also possible to perform both automatic increase and decrease according to the user input.

Next, after the reproduction of the low frequency reference sound through the automatic increase or decrease of the low frequency reference sound or the increase or decrease according to the user input, if the level setting value of the low frequency sound is stored according to the input of the setting button (S309), the harmonic component level control is performed. The unit 220 cross-plays the mid-frequency reference sound of the fixed level and the high-frequency reference sound of the reference level again to set the level of the high-frequency sound (S311), and then sets the high-frequency until the setting button is input (S313). When the level of the frequency reference sound is increased or decreased (S315) and the setting button is input (S313), the level value of the current high frequency reference sound is stored as the level setting value of the high frequency sound (S317).

Meanwhile, in the embodiment of FIG. 6, the harmonic component level adjusting unit 220 sequentially performs the level setting operation of the low frequency sound and the level setting operation of the high frequency sound, but the level setting of the low frequency sound is performed. The level setting of the low frequency sound may be performed according to the menu selection, and the level setting process of the high frequency sound may be performed separately by selecting the menu for setting the level of the high frequency sound.

In addition, in the above description, when the user inputs a button for setting, the corresponding level value is stored. However, instead of inputting a separate setting button, the current level value is automatically changed even when a menu is selected from the harmonic component level adjustment menu. Can be stored as

In addition, although not shown in the flowchart of FIG. 6, the harmonic component level adjusting unit 220 displays a menu as shown in FIG. 5 before each level setting operation, and whether the current target is a high frequency sound or a low frequency sound. It is preferable to display the recognition and to display the level value of the high frequency / low frequency sound currently being reproduced.

Next, FIG. 7 is a flowchart sequentially illustrating a stereophonic sound reproduction process of the stereoscopic sound optimization method according to an embodiment of the present invention. After the user setting operation of the process shown in FIG. 6 is performed, the stereoscopic sound reproduction process in the multimedia device is performed. To illustrate.

As shown, the stereophonic sound processor 210 of the stereophonic sound optimization apparatus according to the present invention receives the compressed audio file to be reproduced (S401), decodes the compressed file (S403) and converts the digital bitstream into an analog signal. The conversion is made (S405). If it is not a compressed audio file, the decoding process (S403) is omitted.

Next, the stereo sound processor 210 generates harmonics for frequency components below the low cutoff frequency using frequency components of the audio bitstream, and restores the converted analog signal to restore frequency components above the high cutoff frequency. Analyze the frequency spectrum of (S407).

Thereafter, the stereo sound processor 210 analyzes the low frequency components included in the frequency components of the audio bitstream (S409-1), and generates low frequency harmonic components for the audio band (S409-3). If there is a level set value set by the user (S409-5), the level of the low frequency harmonic component is adjusted according to the level set value (S409-7). If there is no user setting value, it will be set as the default level without performing any level adjustment process.

In addition, the stereo sound processor 210 analyzes and detects the harmonic components of the high frequency components in the frequency components of the audio bitstream (S411-1), and generates the harmonic components for the high frequency frequencies lost in the compression process. The component is restored (S411-3), and the level of the restored high frequency component is adjusted to the level set value set by the user (S411-5) (S411-7).

When the level adjustment of the low frequency component and the high frequency component is completed as described above, the stereophonic sound processor unit 210 adjusts the original frequency component, that is, the frequency component of the original audio bitstream, by the level controlled low frequency component and the high frequency component. By mixing and outputting the frequency component, the stereo sound optimized for the user can be reproduced through the small acoustic transducer 140 of the multimedia apparatus 100 (S413).

As those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features, the embodiments described above should be understood as illustrative and not restrictive in all aspects. Should be. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

Therefore, according to the apparatus and method for optimizing the stereoscopic sound of the multimedia apparatus of the present invention, when setting the level of the low frequency sound and the restored high frequency sound generated as a harmonic component in the audible frequency band for the reproduction of the stereoscopic sound in the multimedia device, By playing back the mid-frequency reference sound with each low / high frequency reference sound, the user can listen to the subjective sound and perform the level adjustment optimized for himself. By using low-frequency reference sound and high-frequency reference sound by using algorithm that extends frequency sound and high frequency sound, it has the advantage that accurate level control is possible and low / high frequency sound according to user set level value. By reproducing, the optimum stereoscopic sound can be reproduced.

Claims (84)

Apparatus for reproducing optimal stereophonic sound in a multimedia device that reproduces sound through an acoustic transducer, Analyzes the frequency spectrum of the audio file to be reproduced and generates harmonics to generate low frequency harmonics that generate low frequency sound for frequencies below a certain low pass frequency and high frequency sound for frequencies above the high frequency. The high frequency harmonic component is restored, and the level of the generated low frequency harmonic component and the high frequency harmonic component is adjusted using a level setting value of the low frequency sound set by the user and a level setting value of the high frequency sound. A stereophonic sound processor unit for mixing and outputting a midrange frequency component between a low pass cutoff frequency and a high pass cutoff frequency of the audio file; To play a fixed level midrange reference sound and the low / high frequency reference sound according to the level being increased or decreased, and to set the level of the currently played low / high frequency reference sound to the level of the low frequency sound / high frequency sound. A harmonic component level adjusting unit for providing a corresponding reference sound level as a level setting value to the stereophonic sound processor unit when a user inputs the same; 3D acoustic optimization device of a multimedia device comprising a. The method of claim 1, The harmonic component level control unit, A control unit for controlling the level increase and decrease of the low frequency / high frequency reference sound and the reproduction of the mid frequency reference sound and the low frequency / high frequency reference sound that are cross-reproduced with the mid-frequency reference sound; A mid-frequency reference signal output unit for outputting a mid-frequency reference signal of a fixed level; A low frequency reference signal output unit for outputting a low frequency reference signal of a fixed level; A high frequency reference signal output unit for outputting a high frequency reference signal having a fixed level; A level increasing / decreasing unit for increasing or decreasing the level of the low frequency reference signal output from the low frequency reference signal output unit and the level of the high frequency reference signal output from the high frequency reference signal output unit under the control of the controller; A low frequency reference sound that is a sound of a low frequency reference signal of a predetermined level whose level is increased or decreased by the level increase or decrease unit or a high frequency reference sound that is a sound of a high frequency reference signal; A reference sound reproduction unit for performing cross reproduction; The reference sound level under the control of the controller during user input for setting the level of the low / high frequency reference sound currently reproduced by the reference sound reproducing unit to the level of the low frequency sound / high frequency sound restored during stereo sound reproduction. A level setting value storing unit which stores the value as a level setting value; Stereo sound optimization device of a multimedia device, characterized in that consisting of. The method of claim 2, The control unit, Reproducing the reference sound reproducing unit when a user key is input for setting a low / high frequency reference sound level while the low / high frequency reference sound of a specific level is cross-played through the reference sound reproducing unit. And stops the operation, and stores the level of the low / high frequency reference sound currently reproduced as the level setting value of the low / high frequency sound in the level setting value storage unit. The method of claim 2, The control unit, And the level increase / decrease unit controls to automatically increase or decrease the levels of the low frequency reference signal and the high frequency reference signal by a predetermined time unit. The method of claim 2, The control unit, When a key is input to increase or decrease the level of the low frequency reference sound or the high frequency reference sound reproduced through the reference sound reproducing unit, a level value according to the corresponding key input is transmitted to the level increasing / decreasing unit. The level increase and decrease portion, And a level of the low frequency reference signal or the high frequency reference signal outputted through the reference sound reproducing unit according to the level value transmitted from the control unit, is provided to the reference sound reproducing unit. The method of claim 2, The harmonic component level control unit, An adjustment target display unit for displaying whether the current level setting target is a low frequency sound or a high frequency sound; A level display unit displaying a level value and a level setting range of the low frequency reference sound or the high frequency reference sound output through the current reference sound reproducing unit; A menu display unit displaying a menu including a menu; Stereo sound optimization device of a multimedia device further comprising a. The method according to any one of claims 2 to 6, The mid-frequency reference signal output unit, And an octave band noise signal having a specific frequency of a middle frequency band, which is an audible band of the multimedia apparatus, as a center frequency as a mid frequency reference signal. The method of claim 7, wherein The mid-frequency reference signal, 3D acoustic optimization device of a multimedia device, characterized in that the octave band noise signal having a center frequency of 1kHz. The method according to any one of claims 2 to 6, The low frequency reference signal output unit, A low frequency noise signal generator for generating an octave band low frequency noise signal having a specific frequency in a low frequency band below the audible band of the multimedia apparatus; A low frequency spectrum analyzer for analyzing a spectrum of the generated low frequency noise signal and outputting a frequency component of the low frequency noise signal; Generate a low frequency reference signal using the low frequency noise signal frequency component to generate a harmonic component included in the mid frequency band among the harmonic components of the low frequency noise signal, and output the generated harmonic component as a low frequency reference signal. part; 3D acoustic optimization device of a multimedia device comprising a. The method of claim 9, The low frequency noise signal, 3D acoustic optimization device of a multimedia device, characterized in that the octave band noise signal having a center frequency of 60Hz. The method according to any one of claims 2 to 6, The high frequency reference signal output unit, A high frequency noise signal generator for generating a high frequency noise signal of an octave band having a specific frequency as a center frequency of the mid frequency band of the multimedia apparatus; A high frequency spectrum analyzer for analyzing a spectrum of the generated high frequency noise signal and outputting frequency components of the high frequency noise signal; A high frequency frequency using the high frequency noise signal frequency component to generate a harmonic component included in the high frequency band of the audible band of the high frequency noise signal, and outputting the generated harmonic component as a high frequency reference signal A reference signal generator; 3D acoustic optimization device of a multimedia device comprising a. The method of claim 11, The high frequency noise signal is, Stereo sound optimization device for multimedia equipment, characterized in that the signal of the octave band noise having a center frequency of 8kHz. The method according to any one of claims 1 to 6, The stereophonic processor unit, A DA converter for converting an audio bit stream to be reproduced into an analog signal; A spectrum analyzer for analyzing the spectrum of the converted analog signal and outputting frequency components of the audio bitstream; Extracting a low frequency component below the low frequency cutoff frequency among the frequency components output from the spectrum analyzer, generating a harmonic component included in the audible band among the extracted harmonic components of the low frequency component, and generating the generated low frequency harmonic component A low frequency expansion unit for adjusting and outputting a level to a low frequency sound level setting value provided from the harmonic component level adjusting unit; Detects the harmonics of the high frequency components above the high frequency cutoff frequency among the frequency components output from the spectrum analyzer, and generates the high frequency harmonics based on the detected harmonics to restore the high frequency components lost in the compression process. A high frequency expansion unit for adjusting the generated high frequency harmonic component level to a high frequency sound level setting value provided from the harmonic component level adjusting unit; A mixing unit for mixing the low frequency harmonic component output from the low frequency expansion unit and the high frequency harmonic component output from the high frequency expansion unit with the original frequency component output from the DA converter; 3D acoustic optimization device of a multimedia device comprising a. The method of claim 13, The low frequency extension unit, A low frequency component analyzer for extracting low frequency components below the low frequency cutoff frequency from the frequency components output from the spectrum analyzer; A low frequency harmonic component generating unit for generating a harmonic component included in the audible band among the extracted harmonic components of the low frequency component; If there is a user set value for the low frequency sound level, adjust the output level of the generated low frequency harmonic component according to the set value, and if the user set value does not exist, the low frequency of the preset reference level A low frequency harmonic component level control unit for outputting harmonic components; Stereo sound optimization device of a multimedia device, characterized in that consisting of. The method of claim 13, The high frequency extension unit, A high frequency component analyzer for detecting a harmonic component of the high frequency component of the frequency component output from the spectrum analyzer by the high frequency cutoff frequency or more; A high frequency harmonic component generator for restoring high frequency components lost in the compression process by generating a high frequency harmonic component based on the detected harmonic components; If there is a user setting value for the level of the high frequency sound, the level of the generated high frequency harmonic component is output according to the setting value, and if the user setting value does not exist, the high frequency of the preset reference level A high frequency harmonic component level adjusting unit for outputting harmonic components; Stereo sound optimization device of a multimedia device, characterized in that consisting of. The method of claim 13, The stereophonic processor unit, A decoder unit which decompresses the compressed audio file and inputs it to the DA converter; Stereo sound optimization device of a multimedia device further comprising a. Apparatus for reproducing optimal stereophonic sound in a multimedia device that reproduces sound through an acoustic transducer, Analyze the frequency spectrum of the audio file to be reproduced to generate a low frequency harmonic component for generating a low frequency sound for a frequency component below a certain low frequency cutoff frequency and a high frequency harmonic component for generating a high frequency sound for a frequency component above a predetermined high frequency cut frequency. Generating the low frequency harmonic component and the high frequency harmonic component by using a low frequency sound level setting value set by a user and a high frequency sound level setting value, and then adjusting the low frequency cutoff frequency of the audio file. A stereophonic sound processor for mixing and outputting a midrange frequency component between a high frequency and a high frequency cutoff frequency; 3D acoustic optimization device of a multimedia device comprising a. The method of claim 17, The stereophonic processor unit, A DA converter for converting an audio bit stream to be reproduced into an analog signal; A spectrum analyzer for analyzing the spectrum of the converted analog signal and outputting frequency components of the audio bitstream; Extracting a low frequency component below the low frequency cutoff frequency among the frequency components output from the spectrum analyzer, generating a harmonic component included in the audible band among the extracted harmonic components of the low frequency component, and generating the generated low frequency harmonic component A low frequency expansion unit for adjusting and outputting a level of the low frequency sound level set value provided from the harmonic component level adjusting unit; Detecting the harmonics of the frequency components of the frequency components output from the spectrum analyzer more than the high-frequency cutoff frequency, and generating a high-frequency harmonics based on the detected harmonics to restore the high-frequency components lost in the compression process A high frequency expansion unit for adjusting the generated high frequency harmonic component level to a high frequency sound level setting value provided from the harmonic component level adjusting unit and outputting the high frequency frequency harmonic component; A mixing unit for mixing the low frequency harmonic components and the high frequency harmonic components with the original frequency components output from the DA converter; 3D acoustic optimization device of a multimedia device comprising a. The method of claim 18, The low frequency extension unit, A low frequency component analyzer for extracting low frequency components below the audible band of the multimedia apparatus among the frequency components output from the spectrum analyzer; A low frequency harmonic component generating unit for generating a harmonic component included in the audible band among the extracted harmonic components of the low frequency component; If there is a user set value for the low frequency sound level, adjust the level of the generated low frequency harmonic component according to the set value, and output the low frequency to a preset reference level if the user set value does not exist. A low frequency harmonic component level adjusting unit for outputting sound; Stereo sound optimization device of a multimedia device, characterized in that consisting of. The method of claim 18, The high frequency extension unit, A high frequency component analyzer for detecting a harmonic component of a high frequency component of a frequency component that is lost due to the digital audio compression among the frequency components output from the spectrum analyzer; A high frequency harmonic component generator for restoring high frequency components lost in the compression process by generating a high frequency harmonic component based on the detected harmonic components; If there is a user setting value for the level of the high frequency sound, the level of the generated high frequency harmonic component is output according to the setting value, and if the user setting value does not exist, the high frequency of the preset reference level A high frequency harmonic component level adjusting unit for outputting harmonic components; Stereo sound optimization device of a multimedia device, characterized in that consisting of. The method of claim 18, The stereophonic processor unit, A decoder unit which decompresses the compressed audio file and inputs it to the DA converter; Stereo sound optimization device of a multimedia device further comprising a. Apparatus for reproducing optimal stereophonic sound in a multimedia device that reproduces sound through an acoustic transducer, To play a fixed level midrange reference sound and the low / high frequency reference sound according to the level being increased or decreased, and to set the level of the currently played low / high frequency reference sound to the level of the low frequency sound / high frequency sound. A harmonic component level adjusting unit for providing a corresponding reference sound level as a level setting value to the stereophonic sound processor unit when a user inputs the same; 3D acoustic optimization device of a multimedia device comprising a. The method of claim 22, The harmonic component level control unit, A control unit for controlling the level increase and decrease of the low frequency / high frequency reference sound and the reproduction of the mid frequency reference sound and the low frequency / high frequency reference sound that are cross-reproduced with the mid-frequency reference sound; A mid-frequency reference signal output unit for outputting a mid-frequency reference signal of a fixed level; A low frequency reference signal output unit for outputting a low frequency reference signal of a fixed level; A high frequency reference signal output unit for outputting a high frequency reference signal having a fixed level; A level increasing / decreasing unit for increasing or decreasing the level of the low frequency reference signal output from the low frequency reference signal output unit and the level of the high frequency reference signal output from the high frequency reference signal output unit under the control of the controller; The low-frequency reference sound, which is a low-frequency reference signal of a predetermined level, or the high-frequency reference sound, which is a high-frequency reference signal, whose level is increased or decreased by the level increase / decrease unit, cross-plays with the mid-frequency reference sound, which is the fixed-frequency mid-frequency reference signal. A reference sound reproducing unit; The reference sound level under the control of the controller during user input for setting the level of the low / high frequency reference sound currently reproduced by the reference sound reproducing unit to the level of the low frequency sound / high frequency sound restored during stereo sound reproduction. A level setting value storing unit which stores the value as a level setting value; Stereo sound optimization device of a multimedia device, characterized in that consisting of. The method of claim 23, wherein The control unit, Reproducing the reference sound reproducing unit when a user key is input for setting a low / high frequency reference sound level while the low / high frequency reference sound of a specific level is cross-played through the reference sound reproducing unit. And stops the operation, and stores the level of the low / high frequency reference sound currently reproduced as the level setting value of the low / high frequency sound in the level setting value storage unit. The method of claim 23, wherein The control unit, And the level increase / decrease unit controls to automatically increase or decrease the levels of the low frequency reference signal sound and the high frequency reference signal sound by a predetermined time unit. The method of claim 23, wherein The control unit, When a key is input to increase or decrease the level of the low frequency reference sound or the high frequency reference sound reproduced through the reference sound reproducing unit, a level value according to the corresponding key input is transmitted to the level increasing / decreasing unit. The level increase and decrease portion, And a level of the low frequency reference sound or the high frequency reference sound outputted through the reference sound reproducing unit according to the level value transmitted from the control unit, and providing the reference sound reproducing unit to the reference sound reproducing unit. The method of claim 23, wherein The harmonic component level control unit, An adjustment target display unit for displaying whether the current level setting target is a low frequency sound or a high frequency sound; A level display unit displaying a level value and a level setting range of the low frequency reference sound or the high frequency reference sound output through the current reference sound reproducing unit; A menu display unit displaying a menu including a menu; Stereo sound optimization device of a multimedia device further comprising a. The method according to any one of claims 23 to 27, The mid-frequency reference tone output unit, And an octave band noise signal having a center frequency as a specific frequency of the mid frequency band, which is an audible band of the multimedia apparatus, as a mid frequency reference signal. The method of claim 28, The mid-frequency reference tone, 3D acoustic optimization device of a multimedia device, characterized in that the octave band noise signal having a center frequency of 1kHz. The method according to any one of claims 23 to 27, The low frequency reference beep output unit, A low frequency noise signal generator for generating an octave band low frequency noise signal having a specific frequency in a low frequency band below the audible band of the multimedia apparatus as a center frequency; A low frequency spectrum analyzer for analyzing a spectrum of the generated low frequency noise signal and outputting a frequency component of the low frequency noise signal; A low frequency reference signal sound generator for generating a harmonic component included in the mid frequency band of the sound frequency components of the low frequency noise signal using the low frequency noise signal frequency component and outputting the low frequency reference signal as a low frequency reference signal; 3D acoustic optimization device of a multimedia device comprising a. The method of claim 30, The low frequency reference signal, Stereo sound optimization device for a multimedia device, characterized in that the octave band noise signal having a center frequency of 60Hz. The method according to any one of claims 23 to 27, The high frequency reference beep output unit, A high frequency noise signal generator for generating an octave band high frequency noise signal having a specific frequency as a center frequency among the mid frequency bands of the multimedia apparatus; A high frequency spectrum analyzer for analyzing a spectrum of the generated high frequency noise signal and outputting frequency components of the high frequency noise signal; A high frequency reference signal sound generator for generating a harmonic component included in the high frequency band of the audible band or higher among the harmonic components of the high frequency noise signal by using the high frequency noise signal frequency component and outputting it as a high frequency reference signal. ; 3D acoustic optimization device of a multimedia device comprising a. 33. The method of claim 32, The high frequency reference signal, 3D acoustic optimization device of a multimedia device, characterized in that the octave band noise signal having a center frequency of 8kHz. As a method for reproducing stereoscopic sound in a multimedia device that reproduces sound through an acoustic transducer, (A) Low frequency harmonics to generate low frequency sound for frequency components below a certain low frequency by analyzing the frequency spectrum of the audio file to be played and high frequency to generate high frequency sounds for frequency components above a certain high frequency. Generating a harmonic component; (B) adjusting and outputting the generated low frequency harmonic components and low frequency harmonic components using a level setting value of a low frequency sound set by a user and a level setting value of a high frequency sound; (C) mixing and outputting the output low frequency component and the high frequency component with the mid frequency component of the audio file; Stereo sound optimization method of a multimedia device, characterized in that consisting of. The method of claim 34, wherein Step (A) is (A-1) converting the bitstream of the audio file to be reproduced into an analog signal; (A-2) analyzing the spectrum of the converted analog signal and extracting a low frequency component below a cutoff frequency of an acoustic transducer mounted in the multimedia apparatus among frequency components of the audio bitstream; (A-3) generating a low frequency harmonic component which is a harmonic component included in the audible band among the extracted harmonic components of the low frequency component; Stereo sound optimization method of a multimedia device, characterized in that consisting of. 36. The method of claim 35 wherein Step (B) is, (B-1) determining whether a user setting value for the generated low frequency harmonic component level exists; (B-2) As a result of the determination, when the user set value exists, the level of the generated low frequency harmonic component is output according to the set value, and when the user set value does not exist, the low range of the preset reference level Outputting a frequency overtone component; Stereo sound optimization method of a multimedia device, characterized in that consisting of. The method of claim 34, wherein Step (A) is (A-1) converting the bitstream of the audio file to be reproduced into an analog signal; (A-2) analyzing a spectrum of the converted analog signal and detecting a harmonic component of the high frequency component of the audio band or more of the frequency component of the audio bitstream; (A-3) restoring a high frequency component lost in the compression process by generating a high frequency harmonic component based on the detected harmonic component; Stereo sound optimization method of a multimedia device, characterized in that consisting of. The method of claim 37, Step (B) is, (B-1) determining whether a user setting value for the restored high frequency component level exists; (B-2) As a result of the determination, when a user set value exists, the level of the generated high frequency harmonic component is adjusted according to the set value, and when the user set value does not exist, the high range of the preset reference level is not present. Outputting a frequency overtone component; Stereo sound optimization method of a multimedia device, characterized in that consisting of. The method of claim 34, wherein Before step (A), (A′-1) when the user selects a menu for setting the level value of the low frequency sound, cross-reproducing the mid frequency reference sound of a fixed level and the low frequency reference sound according to the increased or decreased level; (A'-2) when a user input for storing a low frequency sound level value is generated, storing the currently reproduced low frequency reference sound level as a low frequency sound level setting value; Stereo sound optimization method of a multimedia device comprising a. The method of claim 39, The (A'-2) step, When the user input for storing the level value of the low frequency sound is generated, stopping the reference sound crossover reproduction operation, and storing the level of the low frequency reference sound currently being reproduced as a low frequency sound level setting value. Stereo sound optimization method of multimedia equipment. The method of claim 39, In the step (A'-1), And the level of the reproduced low frequency reference sound is automatically increased or decreased by a predetermined time unit. The method of claim 39, In the step (A'-1), And the level of the reproduced low frequency reference sound is increased or decreased according to a user's key input. The method of claim 34, wherein Before step (A), (A′-1) when the user selects a menu for setting a level value of the high frequency sound, cross-reproducing the mid frequency reference sound of a fixed level and the high frequency reference sound according to the increased or decreased level; (A'-2) when a user input for storing the level value of the high frequency sound is generated, storing the currently reproduced high frequency reference sound level as a high frequency sound level setting value; Stereo sound optimization method of a multimedia device comprising a. The method of claim 43, The (A'-2) step, When the user input for storing the level value of the high frequency sound is generated, stopping the reference sound crossover reproduction operation, and storing the level of the currently generated high frequency reference sound as the high frequency sound level setting value. Stereo sound optimization method of multimedia equipment. The method of claim 43, In the step (A'-1), And the level of the high frequency reference sound to be reproduced is automatically increased or decreased by a predetermined time unit. The method of claim 43, In the step (A'-1), And a level of the high frequency reference sound to be reproduced is increased or decreased in response to a user key input. The method of claim 39, The (A'-1) step, The spectral spectrum is generated by generating an octave band low frequency noise signal having a specific frequency of a low frequency band below the cutoff frequency of the multimedia device as a center frequency, and using the frequency component of the low frequency noise signal, Generating a low frequency harmonic component included in the mid frequency band of a harmonic component of a signal; A crossover reproduction of a fixed frequency midrange reference sound, which is an octave band noise signal sound having a specific frequency in the midrange frequency band, which is an audible band of a multimedia device, and a low frequency reference sound of the low frequency harmonic step; Stereo sound optimization method of a multimedia device comprising a. The method of claim 47, The mid-frequency reference sound, An octave band noise signal sound having a center frequency of 1 kHz. The method of claim 47, The low frequency noise signal, An octave band noise signal having a center frequency of 60 Hz. The method of claim 43, The (A'-1) step, Generate a high frequency noise signal of an octave band having a specific frequency as a center frequency among the middle frequency bands of the multimedia device, and analyze the spectrum, and use the frequency component of the high frequency noise signal to generate the high frequency noise signal. Generating a high frequency harmonic component included in the high frequency band of the audible band or higher among the harmonic components; A crossover reproduction of a fixed level midrange frequency reference sound, which is a sound of an octave band noise signal having a specific frequency of the midrange frequency band, which is an audible band of a multimedia device, and the high frequency harmonic component of the high frequency harmonic component according to the level being increased or decreased Doing; Stereo sound optimization method of a multimedia device comprising a. 51. The method of claim 50, The mid-frequency reference sound, Stereo sound optimization method of a multimedia device, characterized in that the signal sound of octave band noise having a center frequency of 1kHz. 51. The method of claim 50, The high frequency noise signal is, An octave band noise signal having a center frequency of 8 kHz. As a method for reproducing stereoscopic sound in a multimedia device that reproduces sound through an acoustic transducer, (A′-1) when the user selects a menu for setting a level value of the low frequency sound, cross-reproducing the mid-frequency reference sound of a fixed level and the low-frequency reference sound according to the increased or decreased level; (A'-2) when a user input for storing a low frequency sound level value is generated, storing the currently reproduced low frequency reference sound level as a low frequency sound level setting value; Stereo sound optimization method of a multimedia device comprising a. The method of claim 53, The (A'-2) step, When the user input for storing the level value of the low frequency sound is generated, stopping the reference sound crossover reproducing operation, and storing the level of the low frequency reference sound currently being reproduced as a low frequency sound level setting value. Stereo sound optimization method of multimedia equipment. The method of claim 53, In the step (A'-1), And the level of the reproduced low frequency reference sound is automatically increased or decreased by a predetermined time unit. The method of claim 53, In the step (A'-1), And the level of the reproduced low frequency reference sound is increased or decreased according to a user's key input. The method of claim 53, After the step (A'-2), When the multimedia device is requested to play a specific audio file, the frequency spectrum of the audio file to be played is analyzed to generate a low frequency harmonic component, and the level of the low frequency sound set by the user is set. Adjusting and outputting according to a value; Stereo sound optimization method of the multimedia device further comprising a. The method of claim 53, The (A'-1) step, The spectrum is generated by generating an octave band low frequency noise signal having a specific frequency in a low frequency band below the audible band of the multimedia device as a center frequency, and using the frequency component of the low frequency noise signal, Generating a harmonic component included in the midrange frequency band among harmonic components; A crossover reproduction of a low-frequency reference sound of a fixed level mid-frequency reference sound, which is an octave band noise signal sound having a specific frequency of a mid-frequency band, which is an audible band of a multimedia device, and the low-frequency noise signal according to an increased or decreased level step; Stereo sound optimization method of a multimedia device comprising a. The method of claim 58, The mid-frequency reference sound, An octave band noise signal sound having a center frequency of 1 kHz. The method of claim 58, The low frequency noise signal, An octave band noise signal having a center frequency of 60 Hz. As a method for reproducing stereoscopic sound in a multimedia device that reproduces sound through an acoustic transducer, (A′-1) when the user selects a menu for setting the level value of the high frequency sound, cross-reproducing the mid frequency reference sound of the fixed level and the high frequency reference sound according to the increased or decreased level; (A'-2) when a user input for storing the level value of the high frequency sound is generated, storing the currently reproduced high frequency reference sound level as a high frequency sound level setting value; Stereo sound optimization method of a multimedia device comprising a. 62. The method of claim 61, The (A'-2) step, When the user input for storing the level value of the high frequency sound is generated, stopping the reference sound crossover reproduction operation, and storing the level of the currently generated high frequency reference sound as the high frequency sound level setting value. Stereo sound optimization method of multimedia equipment. 62. The method of claim 61, In the step (A'-1), And the level of the high frequency reference sound to be reproduced is automatically increased or decreased by a predetermined time unit. 62. The method of claim 61, In the step (A'-1), And a level of the high frequency reference sound to be reproduced is increased or decreased in response to a user key input. 62. The method of claim 61, After the step (A'-2), When the multimedia device is requested to play a specific audio file, the frequency spectrum of the audio file to be reproduced is analyzed to generate a high frequency harmonic component of a predetermined frequency or more, thereby restoring the high frequency component lost from the audio file and generating the high frequency harmonics. Adjusting and outputting the level of the component according to the level setting value of the high frequency sound set by the user; Stereo sound optimization method of the multimedia device further comprising a. 62. The method of claim 61, The (A'-1) step, An octave band high frequency noise signal having a specific frequency as a center frequency among the middle frequency bands of the multimedia device is analyzed and spectrum is analyzed, and the harmonics of the high frequency noise signal are extracted using the frequency component of the high frequency noise signal. Generating a high frequency reference signal which is a harmonic component included in the high frequency band of the component or more of the audible band; A crossover reproduction of a fixed level midrange frequency reference sound, which is an octave band noise signal sound having a specific frequency in the midrange frequency band, which is an audible band of a multimedia device, and a high frequency reference tone, which is the high frequency reference signal sound according to an increased or decreased level, step; Stereo sound optimization method of a multimedia device comprising a. The method of claim 66, The mid-frequency reference sound, An octave band noise signal sound having a center frequency of 1 kHz. The method of claim 66, The high frequency noise signal is, An octave band noise signal having a center frequency of 8 kHz. A computer-readable recording medium recording a program for realizing an optimal stereophonic sound reproduction function in a multimedia device that reproduces sound through an acoustic transducer, (A) Analyzing the frequency spectrum of the audio file to be reproduced, and using the harmonic component, a low frequency harmonic component for generating a low frequency sound for a frequency component below a predetermined low frequency cutoff frequency and a high frequency frequency for a frequency component above a certain high frequency cutoff frequency. A first function of generating a high frequency harmonic component for generating sound; (B) a second function of adjusting and outputting the generated low frequency harmonic components and high frequency harmonic components using a level setting value of a low frequency sound set by a user and a level setting value of a high frequency sound; (C) a third function of reproducing the output low frequency harmonic component and high frequency harmonic component by mixing with the mid frequency component of the audio file; And a computer-readable recording medium having recorded thereon a program for realizing an optimal stereophonic sound reproduction function. The method of claim 69, wherein The above (A) function, (A-1) converting a bitstream of an audio file to be reproduced into an analog signal; (A-2) analyzing a spectrum of the converted analog signal and extracting a low frequency component below the audio band of the multimedia apparatus among frequency components of the audio bit stream; (A-3) generating a harmonic component included in the audible band among the extracted harmonic components of the low frequency component; And a computer-readable recording medium having recorded thereon a program for realizing an optimal stereophonic sound reproduction function. The method of claim 69, wherein The above (A) function, (A-1) converting a bitstream of an audio file to be reproduced into an analog signal; (A-2) analyzing a spectrum of the converted analog signal and detecting a harmonic component for a high frequency component of the audio band or more of the audible band from among frequency components of the audio bitstream; (A-3) restoring the high frequency components lost in the compression process based on the detected harmonic components; And a computer-readable recording medium having recorded thereon a program for realizing an optimal stereophonic sound reproduction function. The method of claim 69, wherein The (B) function, (B-1) a function for determining whether or not a user setting value exists for the level of the low frequency sound and the high frequency sound; (B-2) As a result of the determination, when a user set value exists, the level of the generated low frequency harmonic component and the high frequency harmonic component is adjusted and output according to the set value, and when the user set value does not exist in advance, Outputting a low frequency harmonic component and a high frequency harmonic component of a set reference level; And a computer-readable recording medium having recorded thereon a program for realizing an optimal stereophonic sound reproduction function. A computer-readable recording medium that records a program for realizing an optimal stereophonic sound reproduction function in a multimedia device that reproduces sound through an acoustic transducer. (A'-1) When the user selects a menu for setting the level value of the low / high frequency sound, the mid-frequency reference sound of the fixed level and the low / high frequency reference sound according to the increased or decreased level are alternately reproduced. Function; (A'-2) when a user input for storing the level value of the low / high frequency sound occurs, storing a level of the low / high frequency reference sound currently reproduced as a low / high frequency sound level setting value; And a computer-readable recording medium having recorded thereon a program for realizing an optimal stereophonic sound reproduction function. The method of claim 73, The (A'-1) function is A computer-readable recording medium having recorded thereon a program for realizing an optimal stereophonic sound reproducing function, wherein the low / high frequency reference sound is automatically increased or decreased in a predetermined time unit. The method of claim 73, The (A'-1) function is And a program for realizing an optimal stereophonic sound reproducing function, wherein the low / high frequency reference sound is increased or decreased in response to a user key input. The method of claim 73, The (A'-1) function is A function of generating an octave band low frequency noise signal having a specific frequency in a low frequency band below the cutoff frequency of the multimedia apparatus acoustic transducer as a center frequency; Analyzing a spectrum of the generated low frequency noise signal and outputting a frequency component of the low frequency noise signal; A function of generating a low frequency harmonic component included in the mid frequency band of the sound frequency components of the low frequency noise signal by using the low frequency noise signal frequency component; And A crossover reproduction of a fixed frequency midrange reference sound, which is an octave band noise signal sound having a specific frequency in the midrange frequency band, which is an audible band of a multimedia device, and a low frequency reference sound of the low frequency harmonic function; And a computer-readable recording medium having recorded thereon a program for realizing an optimal stereophonic sound reproduction function. 77. The method of claim 76, The mid-frequency reference sound, A computer-readable recording medium characterized by an octave band noise signal with a center frequency of 1 kHz. 77. The method of claim 76, The low frequency noise signal, A computer-readable recording medium characterized by an octave band noise signal having a center frequency of 60 Hz. The method of claim 73, The (A'-1) function is A function of generating an octave band high frequency noise signal having a specific frequency as a center frequency of the mid frequency band of the multimedia apparatus; Analyzing a spectrum of the generated high frequency noise signal and outputting a frequency component of the high frequency noise signal; A function of generating a high frequency harmonic component included in a high frequency band above a cutoff frequency by the digital audio compression out of the harmonic components of the high frequency noise signal using the high frequency noise signal frequency component; And A crossover reproduction of a fixed level midrange frequency reference sound, which is an octave band noise signal sound having a specific frequency in the midrange frequency band, which is an audible band of a multimedia device, and the high frequency reference sound of the high frequency harmonic component according to the level of increase and decrease function; And a computer-readable recording medium having recorded thereon a program for realizing an optimal stereophonic sound reproduction function. The method of claim 79, The mid-frequency reference sound, A computer-readable recording medium characterized by an octave band noise signal with a center frequency of 1 kHz. The method of claim 79, The high frequency noise signal is, A computer-readable recording medium characterized by an octave band noise signal with a center frequency of 8 kHz. The method of claim 73, (A'-3) When the multimedia device is requested to play a specific audio file, the frequency spectrum of the audio file to be reproduced is analyzed to generate a harmonic component to restore the low / high frequency components, and to restore the restored low / high frequency components. Adjusting and outputting a level according to a level setting value of a low / high frequency sound set by the user; A computer-readable recording medium having recorded thereon a program for realizing an optimal stereophonic sound reproducing function, further comprising: a. The method of claim 73, (A'-4) an adjustment object display function for displaying whether the current level setting object is a low frequency sound or a high frequency sound; A computer-readable recording medium having recorded thereon a program for realizing an optimal stereophonic sound reproducing function, further comprising: a. The method of claim 73, (A'-5) a level display function for displaying a level value and a level setting range of the current low frequency reference sound or the high frequency reference sound; A computer-readable recording medium having recorded thereon a program for realizing an optimal stereophonic sound reproducing function, further comprising: a.

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