JP2010181824A - Sound simulation apparatus and sound simulation program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently perform sound simulation by more accurately calculating a sound pressure level than in simulation by only direct sound, and by shortening calculation time of the sound level, while reducing time and effort required for input operation. <P>SOLUTION: A sound simulation apparatus 2 comprises: an input receiving section 31 for receiving input of a total surface area of a room where a loud loudspeaker 18 is installed and an average sound absorbing rate in the room; a first sound pressure level calculation section 33 for calculating a sound pressure level of the direct sound which is directly transmitted from the loud loudspeaker 18 to a sound receiving point; a second sound pressure level calculation section 34 for calculating a sound pressure level of a diffused sound which is diffused from the loud loudspeaker 18 to the room based on the total surface area and the average sound absorbing rate received by the input receiving section 31; and a third sound pressure level calculation section 35 for calculating a sound level of the receiving point based on the sound pressure level of the direct sound and the sound pressure level of the diffusion sound. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an acoustic simulation apparatus and an acoustic simulation program for calculating, by calculation, what kind of sound pressure level a sound emitted from a sound source provided in a room has at a predetermined sound receiving point.

  Conventionally, when a sound source such as a speaker is installed in a room such as a hall, an acoustic simulation using a computer has been performed in order to analyze a sound pressure level or a frequency characteristic at a specific sound receiving point (for example, Patent Documents). 1). As one of calculation methods in such acoustic simulation, there is a method for calculating a sound pressure level in consideration of only a direct sound propagating directly from a sound source toward a sound receiving point. However, when the sound source is installed indoors, the reflected sound that is reflected once or more on the wall surface or the like actually reaches the sound receiving point. Therefore, in the simulation using only direct sound, the sound level is lower than the actual sound pressure level. Therefore, an accurate sound pressure level cannot be obtained.

  On the other hand, as another calculation method in the acoustic simulation, there is a geometric acoustic simulation that performs calculation in consideration of not only the direct sound but also the reflected sound that is reflected at least once by a wall surface or the like. In geometric acoustic simulation, the three-dimensional shape data of the room where the sound source is installed and the sound absorption coefficient for each frequency such as each wall surface are input in advance, so that reflection is performed at least once on each wall surface, ceiling, floor surface, etc. Since all the reflected sounds reaching the sound receiving point are calculated and the simulation is performed, a more accurate sound pressure level can be obtained.

Japanese Patent Laid-Open No. 7-83751

  However, in the case of geometric acoustic simulation, when inputting indoor three-dimensional shape data, it is necessary to accurately input the position, shape, etc. of each wall surface. In addition, since it is necessary to simultaneously input the sound absorption coefficient for each frequency such as each wall surface, ceiling, floor surface, etc., it may take a long time to input until the simulation is started. For example, such an input operation may take several days to several weeks, which is a serious problem when performing geometric acoustic simulation.

  In the calculation process in the geometric acoustic simulation, each reflected sound is calculated based on the three-dimensional shape data input as described above and the sound absorption coefficient on each wall surface, and finally the sound receiving point. However, since the amount of computation in this case is enormous, it is necessary to obtain the sound pressure level at the sound receiving point considering the direct sound and all the reflected sounds. There is a problem that it takes a lot of time.

  The present invention has been made for the purpose of solving the above-described conventional problems, and enables calculation of a sound pressure level with higher accuracy than a simulation using only direct sound, and further reduces labor required for input work. However, it is an object to provide an acoustic simulation apparatus and an acoustic simulation program that can efficiently perform arithmetic processing until a sound pressure level is calculated.

  In order to achieve the above object, an invention according to claim 1 is an acoustic simulation apparatus for calculating, by calculation, a sound pressure level at a predetermined sound receiving point in the room when sound is emitted from a sound source provided in the room. Input receiving means for receiving inputs of the total surface area in the room and the average sound absorption coefficient in the room, and a first sound pressure level for directly propagating from the sound source toward the sound receiving point. A second sound pressure for calculating a sound pressure level of diffused sound diffused from the sound source into the room based on the sound pressure level calculating means and the total surface area and the average sound absorption coefficient received by the input receiving means; Based on the sound pressure level of the direct sound calculated by the level calculating means, the first sound pressure level calculating means, and the sound pressure level of the diffused sound calculated by the second sound pressure level calculating means. Is characterized in that it comprises a third sound pressure level calculating means for calculating the sound pressure level at the sound receiving point are.

  According to this invention, since the sound pressure level at the sound receiving point is calculated in consideration of not only the direct sound but also the diffused sound, the sound pressure level can be calculated with higher accuracy than the simulation using only the direct sound. . In addition, as the information for calculating the diffused sound, it is configured to input the total surface area of the room and the average sound absorption coefficient in the room. Therefore, it is not necessary to input the sound absorption coefficient, and the labor required for input work can be reduced. Furthermore, since the time required for the arithmetic processing is shortened, simulation can be performed efficiently.

  The invention according to claim 2 is the acoustic simulation apparatus according to claim 1, further comprising storage means for previously storing a plurality of types of data relating to the average sound absorption coefficient, wherein the input receiving means is stored in the storage means. It is characterized in that selection of one data from the stored plural types of data is accepted.

  According to this invention, when inputting the average sound absorption rate for calculating the diffused sound, it is only necessary to select one data from a plurality of types of data stored in the storage means, so that the input work is made more efficient. Can be done automatically.

  According to a third aspect of the present invention, in the acoustic simulation apparatus according to the first or second aspect, the sound source is determined based on a sound pressure level at the sound receiving point calculated by the third sound pressure level calculating means. Control means for determining a control parameter for control and controlling the sound pressure level at the sound receiving point to be a predetermined level is further provided.

  According to this invention, the control based on the simulation result can be performed quickly and with high accuracy. The control in this case includes not only controlling the overall value of the sound pressure level but also controlling the sound pressure level (frequency characteristic) for each frequency.

  According to a fourth aspect of the present invention, in the acoustic simulation apparatus according to the third aspect, the sound source is an array speaker capable of controlling sound directivity, and the first and second sound pressure level calculating means include: The sound pressure level is calculated based on a plurality of control patterns for controlling the directivity of the array speaker, and the third sound pressure level calculating means is configured to calculate the sound pressure level at each sound receiving point for each of the plurality of control patterns. A sound pressure level is calculated, and the control means controls the sound pressure level at the sound receiving point calculated by applying each of the plurality of control patterns to be substantially the same level. .

  According to this invention, even when the directivity of the array speaker is controlled, a change in the sound pressure level can be suppressed.

  The invention according to claim 5 is executed by an information processing device, and calculates a sound pressure level at a predetermined sound receiving point in the room when sound is emitted from a sound source provided in the room to the information processing device. An acoustic simulation program for performing processing, wherein the information processing device receives an input of a total surface area of the room and an average sound absorption rate in the room, and from the sound source toward the sound receiving point. Diffusion from the sound source into the room based on the first sound pressure level calculating step for calculating the sound pressure level of the direct sound directly propagating and the total surface area and the average sound absorption rate received in the input receiving step The second sound pressure level calculating step for calculating the sound pressure level of the diffuse sound to be performed, and the direct sound calculated in the first sound pressure level calculating step. A third sound pressure level calculating step for calculating the sound pressure level at the sound receiving point by adding the pressure level and the sound pressure level of the diffused sound calculated in the second sound pressure level calculating step; It is characterized by executing.

  According to the present invention, the sound pressure level at the sound receiving point can be calculated with higher accuracy than when only the direct sound is simulated, and the input operation for inputting the conditions for performing the simulation is the conventional geometry. This is less than in the case of acoustic simulation. In addition, since the calculation time is shortened, it is possible to perform an acoustic simulation efficiently.

It is a block diagram which shows one structural example of an acoustic system. It is a perspective view which shows one structural example of a speaker apparatus. It is a figure which shows an example of the state which installed the speaker apparatus which is a sound source indoors. It is a block diagram which shows the function structure in CPU when an information processing apparatus functions as an acoustic simulation apparatus. It is a figure which shows an example of typical multiple types of average sound absorption coefficient data. It is a figure which shows an example of the display screen displayed on a display part, when inputting the total surface area and average sound absorption coefficient in a room in an acoustic simulation apparatus. It is a figure which shows the relationship between a certain speaker unit and sound receiving point in a speaker apparatus. It is a figure which shows the virtual sphere installed centering on the speaker apparatus in order to calculate the sound pressure level of a diffused sound. It is a figure which shows an example of the sound pressure level (acoustic characteristic) in the sound receiving point calculated by the sound pressure level calculation part. It is a flowchart which shows an example of the process sequence performed in an acoustic simulation apparatus. It is a figure which shows the sound pressure level in each pattern calculated when changing the control pattern of a speaker apparatus and performing a simulation.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration example of an acoustic system 1 according to the present embodiment. The acoustic system 1 includes a signal processing unit 10 that processes an audio signal, a speaker device 18 that serves as a sound source for generating sound based on the audio signal processed by the signal processing unit 10, and a sound emitted from the speaker device 18. It is the structure provided with the acoustic simulation apparatus 2 which calculates the acoustic characteristic of this by calculation.

  FIG. 2 is a perspective view illustrating a configuration example of the speaker device 18 according to the present embodiment. In the present embodiment, the speaker device 18 is an array speaker in which a plurality of speaker units 181, 182,. This array speaker can control the directivity of the sound emitted from the speaker device 18 by individually controlling the audio signal supplied to each speaker unit. In the illustrated example, the plurality of speaker units 181, 182,..., 18 n is shown as a two-dimensional array arranged in the vertical direction and the horizontal direction. The original array may be used. Further, the number of speaker units arranged in the speaker device 18 as an array speaker is arbitrary, and is not limited to the illustrated example. In this embodiment, the speaker device 18 is used in a state where it is installed in a room 8 such as a hall as shown in FIG.

  1, the signal processing unit 10 includes a signal input unit 11, a level adjustment unit 12, an equalizer 13, array control filters 141, 142,..., 14n, and signal output units 151, 152,. ing. The signal input unit 11 is an interface for inputting an audio signal, and the audio signal input to the signal input unit 11 is output to the level adjustment unit 12. The level adjustment unit 12 is for adjusting the overall sound pressure level of the audio signal. The level adjustment unit 12 is controlled by the acoustic simulation device 2. That is, the parameters for adjusting the sound pressure level in the level adjusting unit 12 are set by the acoustic simulation device 2. Then, the audio signal whose level has been adjusted by the level adjusting unit 12 is output to the equalizer 13. The equalizer 13 is for adjusting the frequency characteristic of the audio signal supplied to the speaker device 18. This equalizer 13 is also controlled by the acoustic simulation apparatus 2. That is, the parameters for each frequency band adjusted in the equalizer 13 are set by the acoustic simulation apparatus 2. The equalizer 13 may be configured by an IIR filter such as a PEQ (parametric equalizer), or may be configured by an FIR filter. The audio signal output from the equalizer 13 is input to a plurality of array control filters 141, 142,.

  The array control filters 141, 142,..., 14 n are individually provided corresponding to the plurality of speaker units 181, 182,. ..., a filter that controls the directivity of the sound emitted from the speaker device 18 by individually adding a delay or gain to the audio signal supplied to 18n. The delay and gain added to the audio signal in each of the array control filters 141, 142,..., 14n are set by the acoustic simulation apparatus 2. The array control filters 141, 142,..., 14n may be FIR filter filters.

  .., 15n are also provided individually corresponding to the plurality of speaker units 181, 182,..., 18n, and are output from the respective array control filters 141, 142,. Are amplified by an amplifier and then output to the corresponding speaker units 181, 182,..., 18n.

  On the other hand, the acoustic simulation apparatus 2 includes an information processing apparatus 20 that is a general computer (PC). The information processing apparatus 20 includes a CPU 21 that performs various arithmetic processes, an operation unit 22 that includes a keyboard and a mouse, a display unit 23 that includes a CRT, an LCD, and the like, and a hard disk that stores various data and programs. A device 24 and a memory 25 for storing temporary data and the like when the CPU 21 performs arithmetic processing are provided. An acoustic simulation program 25 for causing the information processing device 20 to function as the acoustic simulation device 2 is installed in the hard disk device 24 in advance. The hard disk device 24 stores a plurality of types of average sound absorption coefficient data 26 in advance with the installation of the acoustic simulation program 25. The information processing device 20 functions as the acoustic simulation device 2 by the CPU 21 reading and executing the acoustic simulation program 25.

  As shown in FIG. 3, the acoustic simulation apparatus 2 has any sound pressure level at a sound receiving point 9 in the room 8 designated by the user, as a sound emitted from the speaker device 18 provided in the room 8. This is calculated by performing a simulation calculation. In particular, in the simulation in the present embodiment, a direct sound that propagates directly from the speaker device 18 to the sound receiving point 9 and a diffused sound that diffuses from the speaker device 18 into the indoor space are calculated, and these direct sound and diffused sound are calculated. Considering this, the sound pressure level at the sound receiving point 9 is calculated. And the acoustic simulation apparatus 2 determines the control parameter for setting in the level adjustment part 12 or the equalizer 13 based on the calculated sound pressure level, and the acoustic characteristic in a sound receiving point becomes a characteristic which a user desires. To control.

  The acoustic simulation apparatus 2 controls the directivity of the array speaker by setting the delay and gain to each of the array control filters 141, 142,..., 14n based on the control pattern of the speaker apparatus 18 specified by the user. To do. At this time, the acoustic simulation device 2 can also adjust the sound pressure level based on the simulation result so that the sound pressure level does not change significantly before and after the control pattern of the speaker device 18 is changed.

  FIG. 4 is a block diagram illustrating a functional configuration of the CPU 21 when the information processing apparatus 20 functions as the acoustic simulation apparatus 2. The input receiving unit 31 is a processing unit for receiving an input operation from the user via the operation unit 22 and receives input of various conditions for performing a simulation and a desired sound pressure level at a sound receiving point.

  As conditions for performing the simulation, for example, in the case of an acoustic environment as shown in FIG. 3, the configuration and characteristics of the speaker device 18 and the positional relationship between the speaker device 18 and the sound receiving point 9 are input. In the present embodiment, the total surface area of the room 8 and the average sound absorption coefficient in the room 8 are input as conditions for calculating the diffused sound in the room 8. Here, the average sound absorption coefficient of the room 8 is generally different for each frequency. Therefore, the average sound absorption coefficient of the room 8 is input for each frequency. However, if the user must always manually input the average sound absorption coefficient for each frequency in the room 8, the burden on the user for inputting the simulation conditions increases. Therefore, in this embodiment, typical plural types of average sound absorption coefficient data 26 are stored in the hard disk device 24 in advance, and when the user sets the average sound absorption coefficient of the room 8, the plural types of average sound absorption coefficient data 26 are stored. By selecting one average sound absorption coefficient data from among the above, the average sound absorption coefficient for each frequency can be automatically set.

  FIG. 5 is a diagram illustrating an example of a plurality of types of average sound absorption coefficient data 26 stored in the hard disk device 24. As shown in FIG. 5, the average sound absorption rate data 26 stores in advance the average sound absorption rate for each average frequency in a typical acoustic space such as a studio, a church, a banquet room, or a concert hall. The average sound absorption rate data 26 stores the average sound absorption rate data for each frequency previously input by the user as user memories 1, 2, and 3. Therefore, when the user inputs the average sound absorption rate as a simulation condition in the acoustic simulation device 2, the user is closest to the acoustic space of the room 8 in which the speaker device 18 is installed from among the plural types of average sound absorption rate data 26. Select data.

  FIG. 6 is a diagram illustrating an example of a display screen displayed on the display unit 23 by the input receiving unit 31 when receiving an input of the total surface area of the room 8 and the average sound absorption rate in the acoustic simulation apparatus 2. As shown in FIG. 6, the display unit 23 displays an area input field 23 a for inputting the total surface area of the room 8 and an average sound absorption rate input field 23 b for inputting the average sound absorption rate. In the area input field 23a, for example, the total surface area of the room 8 calculated by the user by manual calculation or the like is input using a numeric keypad. A pull-down button 23c is displayed on the right side of the average sound absorption rate input field 23b. When the user clicks the pull-down button 23c by operating a mouse or the like, a plurality of types of averages are displayed below the average sound absorption rate input field 23b. The sound absorption coefficient data 26 is displayed as a pull-down menu 23d. Therefore, the user can designate the average sound absorption coefficient by selecting the average sound absorption coefficient data most suitable for the space in the room 8 from the pull-down menu 23d. In the example shown in the figure, “2300” is input as the total surface area of the room 8, and “church (live)” is selected as the average sound absorption coefficient.

  In addition to the above, the input receiving unit 31 also has, as a condition for performing the simulation, for example, control parameters set in the level adjusting unit 12 and the equalizer 13, a control pattern for controlling the directivity of the speaker device 18, and the like. The input of various information is also accepted.

  When all the information necessary for performing the simulation is input, the CPU 21 starts a calculation process for the simulation based on the input information. At this time, the CPU 21 functions as a sound pressure level calculation unit 32 as shown in FIG. The sound pressure level calculation unit 32 further functions as a first sound pressure level calculation unit 33, a second sound pressure level calculation unit 34, and a third sound pressure level calculation unit 35. The first sound pressure level calculation unit 33 is a processing unit for calculating the sound pressure level of the direct sound that propagates directly from the speaker device 18 that is a sound source toward the sound receiving point 9 designated by the user. The second sound pressure level calculation unit 34 is a processing unit for calculating the sound pressure level of diffused sound diffusing from the speaker device 18 into the room 8 based on the total surface area of the room 8 and the average sound absorption coefficient. . Then, the third sound pressure level calculator 35 calculates the sound pressure level of the direct sound calculated by the first sound pressure level calculator 33 and the sound of the diffuse sound calculated by the second sound pressure level calculator 34. It is a processing unit that calculates the sound pressure level at the sound receiving point 9 based on the pressure level. In the present embodiment, the sound pressure at the sound receiving point 9 including both the direct sound and the diffused sound is obtained by sequentially performing arithmetic processing in each of the first to third sound pressure level calculation units 33 to 35. A level is calculated. This will be described in more detail below.

  First, calculation processing in the first sound pressure level calculation unit 33 will be described. The first sound pressure level calculation unit 33 calculates the sound pressure level of the direct sound that propagates to the sound receiving point 9 for each of the plurality of speaker units 181, 182,..., 18 n included in the speaker device 18. Then, the sound pressure level by the direct sound from the speaker device 18 is calculated by adding the sound pressure level from each speaker unit.

  FIG. 7 is a diagram showing the relationship between the i-th speaker unit (where i is an arbitrary number satisfying 1 ≦ i ≦ n) and the sound receiving point 9. As shown in FIG. 7, the azimuth angle with respect to the sound receiving point 9 is θi, the elevation angle is φi, and the distance to the sound receiving point 9 (m ) Is ri, the transfer function from the i-th speaker unit to the sound receiving point 9 is expressed by the following equation (1).

  Here, f is a frequency (Hz) and λ is a wavelength (m). Di (f, θi, φi) is a directivity coefficient of the i-th speaker unit, and is a different coefficient for each frequency. This directivity coefficient is a coefficient specific to the speaker unit, and indicates how many times the energy in the direction of the azimuth angle θi and the elevation angle φi becomes the reference energy in the Z-axis direction. Such a directivity coefficient is determined based on the configuration and characteristics of the speaker device 18. Further, m (f) is a sound attenuation coefficient (1 / m) due to air absorption, and is a different coefficient for each frequency.

  Further, as shown in FIG. 7, the sound pressure P1i at a point on the Z-axis that is 1 m away from the front side of the i-th speaker unit is calculated. This sound pressure P1i reflects the configuration and characteristics of the speaker device 18 and the setting state of each part (the level adjustment unit 12, the equalizer 13, the array control filter 14i, and the signal output unit 15i) in the signal processing unit 10. It can be calculated by performing the following calculation. When the sound pressure P1i at the 1m point is calculated, the sound pressure Pi (f) of the direct sound propagating from the i-th speaker unit to the sound receiving point 9 is expressed by It is expressed by an expression.

  By performing the calculation based on the equation (2), the sound pressure Pi (f) of the direct sound that propagates directly from the i-th speaker unit to the sound receiving point 9 can be calculated. The sound pressure Pd at the sound receiving point 9 due to the direct sound emitted from the entire speaker device 18 is calculated for each speaker unit by calculating the sound pressure Pi (f) calculated based on the above equation (2). Since it is obtained by adding, it is expressed by the following equation (3). In the equation (3), N is the number (n) of speaker units in the speaker device 18.

  The first sound pressure level calculation unit 32 calculates the sound pressure Pd by the direct sound from the speaker device 18 by performing the above calculation. Since the sound pressure Pd is a function of the frequency f, the first sound pressure level calculation unit 32 directly performs the calculation at the sound receiving point 9 by substituting the frequency f into the equation (3). The sound pressure Pd of the sound is calculated for each frequency.

  Next, calculation processing in the second sound pressure level calculation unit 34 will be described. The second sound pressure level calculation unit 34 performs a calculation assuming a virtual sphere installed around the speaker device 18 in order to calculate the sound pressure level due to the diffused sound emitted from the speaker device 18. FIG. 8 is a diagram showing this virtual sphere. As shown in FIG. 8, the second sound pressure level calculation unit 34 subdivides the surface of the virtual sphere with a plurality of meridians and parallels set at equal intervals, and lattice points ( Numbers are assigned to the grids in order. If the number of grid points is M, focus on the j-th grid (where j is an arbitrary number satisfying 1 ≦ j ≦ M), and assume that the grid j is sufficiently far from the speaker device 18. The sound pressure in the grid j is calculated by performing an operation based on the following equation (4).

  Here, P1i is the sound pressure P1i at the point on the Z-axis that is 1 m away from the front side of the i-th speaker unit as described above. Therefore, the sound pressure P1i reflects the setting state of each unit (level adjustment unit 12, equalizer 13, array control filter 14i, and signal output unit 15i) in the signal processing unit 10. The azimuth angle of the grid j with respect to the speaker device 18 is θj, and the elevation angle is φj. Di (f, θi, φi) is the directivity coefficient of the i-th speaker unit as described above. Therefore, the sound pressure at the grid j of the sound emitted from the N speaker units provided as the array speaker is obtained by performing the calculation based on the formula (4).

  Then, the sound output W directed in all directions from the speaker device 18 is obtained by integrating the sound pressure at the grid j obtained by the equation 4 with respect to the entire virtual sphere. That is, the sound output W is expressed by the following equation (5).

Here, ρ is the air density (kg / m 3), and c is the speed of sound (m / s). Further, P0 is the reference sound pressure = 2 × 10 ⁻⁵ (Pa), and r∞ indicates a sufficiently far distance (m). Furthermore, Sj is a subdivided area in the grid j. Note that the formula 5 is a function of the frequency f, and the sound output W for each frequency can be calculated by performing the calculation based on the formula 5 for each frequency.

  When the sound output W of the speaker device 18 calculated by the equation 5 is output to the room 8, the average sound absorption coefficient of the room 8 input by the user is α, and the total surface area of the room 8 is Sa. Then, the energy density Es of the diffused sound existing in the room 8 is obtained by the following equation (6).

  Furthermore, the sound pressure of the diffused sound in the room 8 can be calculated by performing the calculation according to the following expression (7) based on the energy density Es of the diffused sound obtained by the expression (6).

  Therefore, the second sound pressure level calculation unit 34 calculates the sound pressure of the diffused sound that is output from the speaker device 18 in all directions and exists in the room 8 by performing the above calculation. Since Ps in Equation 7 is also a function of the frequency f, the second sound pressure level calculation unit 34 can calculate the room 8 by substituting the frequency f into the Equation 7 above. The sound pressure of the diffuse sound at is calculated for each frequency.

  Next, calculation processing in the third sound pressure level calculation unit 35 will be described. The third sound pressure level calculation unit 35 is based on the sound pressure of the direct sound at the sound receiving point 9 and the sound pressure of the diffused sound, and the sound pressure level at the sound receiving point 9 including the direct sound and the diffused sound. L is calculated. Specifically, the sound pressure level L is calculated by performing an operation based on the following equation (8).

  Here, the sound pressure Pd due to only the direct sound is calculated by the first sound pressure level calculation unit 33, and the sound pressure Ps due to the diffused sound is calculated by the second sound pressure level calculation unit 34. The reference sound pressure P0 is a known value defined in advance. Therefore, the third sound pressure level calculation unit 35 calculates the sound pressure level in consideration of both the direct sound and the diffused sound at the sound receiving point 9 by substituting the respective values into the formula 8 and performing the calculation. L can be calculated. Since L in Expression 8 is also a function of the frequency f, the third sound pressure level calculation unit 35 performs sound calculation by substituting the frequency f into Expression 8 above. The sound pressure level L considering both the direct sound and the diffused sound at the point 9 can be calculated for each frequency. Therefore, the frequency characteristic at the sound receiving point 9 can be calculated, and the overall value (OA value) can be calculated based on the sound pressure level L for each frequency.

  FIG. 9 is a diagram illustrating an example of a sound pressure level (frequency characteristic) at the sound receiving point 9 calculated by performing the above-described calculation in the sound pressure level calculation unit 32. In the illustrated example, the sound pressure level characteristic T1 indicates a characteristic calculated by simulating both a direct sound and a diffused sound by the above-described calculation. Further, the sound pressure level characteristic T2 is a comparative example, and indicates a specification calculated by simulating only a direct sound. When the sound pressure level at the sound receiving point 9 is actually measured, the measured value is larger than the sound pressure level characteristic T2 in which only the direct sound is simulated. growing. On the other hand, the sound pressure level characteristic T1 calculated by the simulation of the present embodiment is closer to the actual measurement value than the sound pressure level characteristic T2 which simulates only the direct sound, and the sound pressure level in the low frequency range. A sound pressure level larger than the characteristic T2 is calculated. Therefore, in the simulation in the present embodiment, the sound pressure level L at the sound receiving point 9 can be calculated with high accuracy as compared with the case where only the direct sound is simulated.

  Further, regarding the calculation time of the simulation, the calculation time required for the simulation of the present embodiment is shorter than that of the conventional geometric acoustic simulation. In other words, in the conventional geometric acoustic simulation, it is necessary to calculate each reflected sound based on detailed three-dimensional shape data and the sound absorption rate at each wall surface, However, in this embodiment, the diffused sound that diffuses almost uniformly in the room 8 is calculated, so the reflection angle on the wall surface and the like can be calculated. It is not necessary to calculate each reflected sound that reaches the sound receiving point while calculating, and the calculation amount is reduced, so that efficient calculation is possible.

  Furthermore, in the simulation according to the present embodiment, not the reflected sound but the diffused sound is calculated. Therefore, the user may input the total surface area of the room 8 and the average sound absorption rate of the room 8. That is, since it is not necessary to input detailed indoor three-dimensional shape data as in the conventional geometric acoustic simulation, it is possible to reduce the user's input work.

  When the sound pressure level L is calculated in consideration of both the direct sound and the diffused sound at the sound receiving point 9 as described above, the sound pressure level analysis unit 36 shown in FIG. The sound pressure level analysis unit 36 displays the sound pressure level L at the sound receiving point 9 calculated by the sound pressure level calculation unit 32 on the display unit 23 and is desired by a user input via the operation unit 22. The calculated sound pressure level L is analyzed, for example, by comparison with the sound pressure level.

  When the calculated sound pressure level L is different from the sound pressure level desired by the user, the control unit 37 functions to control the signal processing unit 10. The control unit 37 determines a control parameter for adjusting the level adjusting unit 12 and the equalizer 13 based on the difference between the sound pressure level L and the sound pressure level desired by the user, and the control parameter is set to the level adjusting unit 12 or By setting the equalizer 13, the sound pressure level L at the sound receiving point 9 is controlled to the sound pressure level desired by the user. Note that the control parameter determined by the control unit 37 may be input again to the sound pressure level calculation unit 32 so that the sound pressure level calculation unit 32 performs the simulation calculation again based on the determined control parameter. .

  FIG. 10 is a flowchart illustrating an example of a processing procedure for realizing each function described above in the CPU 21. This process is started when the CPU 21 reads and executes the acoustic simulation program 25. When the process starts, the acoustic simulation apparatus 2 first receives an input of conditions for performing a simulation (step S11). Here, various kinds of information necessary for performing the above-described calculation are input. At this time, the screen shown in FIG. 6 is displayed on the display unit 23, and inputs of the total surface area of the room 8 and the average sound absorption rate of the room 8 necessary for calculating the diffused sound are accepted. At this time, an input of a sound pressure level desired by the user may be accepted.

  When the input of the conditions for performing the simulation is completed, the acoustic simulation device 2 performs calculation calculation of the sound pressure level by the direct sound (step S12). Here, the first sound pressure level calculator 33 described above functions in the CPU 21 to calculate the sound pressure level Pd of the direct sound at the sound receiving point 9. Next, the acoustic simulation device 2 performs calculation calculation of the sound pressure level due to the diffused sound (step S13). Here, the second sound pressure level calculation unit 34 described above functions in the CPU 21, and the sound pressure level Ps of diffused sound in the room 8 is calculated. Thereafter, the acoustic simulation device 2 performs a calculation operation of the sound pressure level L at the sound receiving point 9 obtained by adding both the direct sound and the diffused sound (step S14). Here, the third sound pressure level calculation unit 34 described above functions in the CPU 21, and the sound pressure level L due to both the direct sound and the diffused sound at the sound receiving point 9 in the room 8 is calculated.

  Then, the acoustic simulation device 2 determines whether there are other conditions for performing the simulation (step S15). For example, if the sound pressure level L at a specific frequency is calculated in steps S12 to S14 described above, the answer is YES if the sound pressure level L at another frequency needs to be calculated. Moreover, it becomes YES also when performing a simulation by changing the control pattern which controls the directivity of the speaker apparatus 18. FIG. Then, the calculation process in steps S12 to S14 described above is repeatedly executed by changing the conditions for performing the simulation. On the other hand, if there are no other conditions for performing the simulation, NO is determined in step S15.

  The acoustic simulation device 2 analyzes the sound pressure level L at the sound receiving point calculated in step S14 (step S16). At this time, the analysis may be performed based on the sound pressure level L calculated for each frequency, or the analysis may be performed based on the overall value (OA value) of the sound pressure level L calculated for each frequency. Also good. Which is used for the analysis depends on the analysis conditions set by the user. For example, when it is desired to suppress the change in the sound pressure level L caused by changing the control pattern of the speaker device 18 that is an array speaker, it is preferable to perform an analysis based on the overall value. In addition, when it is desired to adjust the frequency characteristic at the sound receiving point 9 so as to be a characteristic desired by the user, it is preferable to analyze the frequency characteristic based on the sound pressure level L calculated for each frequency.

  FIG. 11 is a diagram illustrating the overall values of the sound pressure levels L1 to L5 calculated when the simulation is performed by changing the control pattern of the speaker device 18 to patterns 1 to 5. FIG. When the control pattern of the speaker device 18 is changed, the sound pressure levels L1 to L5 at the sound receiving point 9 become different values as shown in FIG. Therefore, when it is desired to suppress the change in the sound pressure level L due to the change in the control pattern, the acoustic simulation device 2 has a predetermined level between the maximum value and the minimum value of the plurality of sound pressure levels L1 to L5 shown in FIG. It is determined whether there is a difference as described above.

  When it is desired to set the sound pressure level L for each frequency to a sound pressure level desired by the user, the acoustic simulation device 2 determines whether the sound pressure level characteristic T1 shown in FIG. 9 is different from the frequency characteristic desired by the user. Determine whether.

  Then, the acoustic simulation device 2 determines whether or not the signal processing unit 10 needs to be controlled based on the analysis result of the sound pressure level L (step S17), and ends the processing when it is not necessary to control the signal processing unit 10. . If the control is necessary, the process proceeds to the next step, and a control parameter for controlling at least one of the level adjusting unit 12 and the equalizer 13 is determined (step S18). For example, when it is desired to suppress the change in the sound pressure levels L1 to L5 accompanying the change in the control pattern as shown in FIG. 11, the acoustic simulation device 2 uses a plurality of sound pressure levels when each of the plurality of control patterns is applied. The control parameters for the level adjustment unit 12 are determined so that L1 to L5 are substantially at the same level. At this time, the control parameter at the time of applying each control pattern may be determined so that the average level AL of the plurality of sound pressure levels L1 to L5 is substantially the same, or a desired sound pressure level input by the user is targeted. The control parameter at the time of applying each control pattern may be determined so that the level TL is substantially the same as the target level TL. In addition, for example, when the sound pressure level L for each frequency is desired to be set to a frequency characteristic desired by the user, the acoustic simulation device 2 adjusts the sound pressure level for each frequency based on the difference from the frequency characteristic desired by the user. A control parameter for the equalizer 13 is determined. A control parameter for controlling both the level adjustment unit 12 and the equalizer 13 may be determined.

  When the control parameter is determined, the acoustic simulation apparatus 2 controls the sound pressure level by setting the determined control parameter for the level adjusting unit 12 and / or the equalizer 13 (step S19). This process is completed. However, when the simulation is performed again with the control parameter set, the process procedure may be such that the above process is repeatedly executed.

  As described above, the acoustic simulation device 2 according to the present embodiment is capable of both direct sound propagating directly from the speaker device 18 toward the sound receiving point 9 in the room 8 and diffused sound diffusing from the speaker device 18 into the room 8. Based on this, the sound pressure level at the sound receiving point 9 is calculated, and the sound pressure level at the sound receiving point 9 can be calculated with higher accuracy than the conventional simulation using only direct sound. In addition, the acoustic simulation apparatus 2 according to the present embodiment uses two pieces of information of the total surface area of the room 8 and the average sound absorption rate in the room 8 as input information by the user in order to calculate diffuse sound. Therefore, when the sound pressure level simulation is performed using the acoustic simulation apparatus 2, the user does not need to input complicated three-dimensional shape data of the room 8, and does not need to input the sound absorption coefficient for each wall surface. . Therefore, the input operation of the conditions for performing the simulation can be completed quickly, and the burden on the user can be reduced.

  In the present embodiment, representative plural types of average sound absorption rate data 26 are stored in advance, and therefore, when inputting the average sound absorption rate of the room 8, the average sound absorption rate data 26 of the plurality of types is selected. The average sound absorption rate can be set by selecting data most suitable for the acoustic space in the room 8. Therefore, it is not necessary for the user to calculate the average sound absorption coefficient for each frequency in the room 8 in which the speaker device 18 is installed by hand calculation, and the input work can be made more efficient in this respect. However, it is not always necessary to select from a plurality of representative types of average sound absorption coefficient data 26, and in order to further improve the accuracy of the simulation, the wall surface of the room 8 where the speaker device 18 is installed. An average sound absorption coefficient for each frequency in the room 8 may be calculated based on the material and the like, and may be input.

  In addition, the acoustic simulation device 2 of the present embodiment shortens the calculation time required for the simulation as compared with the conventional geometric acoustic simulation. Therefore, even when the simulation is repeatedly performed by changing the conditions, the result is efficiently obtained. You can refer to it.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the content mentioned above.

  For example, in the above-described embodiment, the case where the speaker device 18 is an array speaker has been described, but the present invention is not necessarily limited to being an array speaker. For example, when the number of speaker units is one, the sound pressure level L at the sound receiving point 9 can be calculated by performing calculation with N = 1 in each of the above formulas when performing the simulation. Further, even when there are a plurality of speaker units, in the case of a speaker device having a divided band such as a 2WAY speaker or a 3WAY speaker instead of an array speaker capable of controlling directivity, N = A simulation can be performed with an arithmetic expression of 1.

DESCRIPTION OF SYMBOLS 1 Acoustic system 2 Acoustic simulation apparatus 8 Room 9 Sound receiving point 10 Signal processing part 18 Speaker (sound source)
20 Information processing device 24 Hard disk device (storage means)
25 Sound simulation program 26 Average sound absorption coefficient data 31 Input reception unit (input reception means)
33 1st sound pressure level calculation part (1st sound pressure level calculation means)
34 2nd sound pressure level calculation part (2nd sound pressure level calculation means)
35 Third sound pressure level calculation unit (third sound pressure level calculation means)
37 Control part (control means)

Claims (5)

An acoustic simulation device for calculating a sound pressure level at a predetermined sound receiving point in the room when sound is emitted from a sound source provided in the room by calculation,
Input receiving means for receiving input of the total surface area in the room and the average sound absorption coefficient in the room;
First sound pressure level calculating means for calculating a sound pressure level of a direct sound that propagates directly from the sound source toward the sound receiving point;
Second sound pressure level calculating means for calculating a sound pressure level of diffused sound diffused from the sound source into the room based on the total surface area and the average sound absorption coefficient received by the input receiving means;
Based on the sound pressure level of the direct sound calculated by the first sound pressure level calculating means and the sound pressure level of the diffuse sound calculated by the second sound pressure level calculating means, Third sound pressure level calculating means for calculating the sound pressure level;
An acoustic simulation apparatus comprising: A storage means for storing a plurality of types of data relating to the average sound absorption rate in advance;
The acoustic simulation apparatus according to claim 1, wherein the input receiving unit receives selection of one data from the plurality of types of data stored in the storage unit.   A control parameter for controlling the sound source is determined based on the sound pressure level at the sound receiving point calculated by the third sound pressure level calculating means, and the sound pressure level at the sound receiving point is predetermined. The acoustic simulation apparatus according to claim 1, further comprising control means for controlling the level. The sound source is an array speaker capable of controlling sound directivity,
The first and second sound pressure level calculation means calculate a sound pressure level based on a plurality of control patterns for controlling the directivity of the array speaker,
The third sound pressure level calculating means calculates a sound pressure level at the sound receiving point for each of the plurality of control patterns;
4. The acoustic simulation according to claim 3, wherein the control means controls the sound pressure level at the sound receiving point calculated by applying each of the plurality of control patterns to be substantially the same level. apparatus. An acoustic simulation program that is executed by an information processing apparatus and causes the information processing apparatus to perform a process of calculating a sound pressure level at a predetermined sound receiving point in the room when sound is emitted from a sound source provided in the room. And
In the information processing apparatus,
An input receiving step for receiving input of the total surface area in the room and the average sound absorption coefficient in the room;
A first sound pressure level calculating step of calculating a sound pressure level of a direct sound that propagates directly from the sound source toward the sound receiving point;
A second sound pressure level calculating step for calculating a sound pressure level of diffused sound diffused from the sound source into the room based on the total surface area and the average sound absorption coefficient received in the input receiving step;
The sound receiving point is obtained by adding the sound pressure level of the direct sound calculated in the first sound pressure level calculating step and the sound pressure level of the diffused sound calculated in the second sound pressure level calculating step. A third sound pressure level calculating step for calculating the sound pressure level at
An acoustic simulation program characterized in that

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