JP3709398B2 - Acoustic characteristic measuring method and acoustic characteristic measuring apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an acoustic characteristic measuring method and an acoustic characteristic measuring apparatus, and more particularly to an acoustic characteristic measuring method and an acoustic characteristic measuring apparatus for measuring acoustic characteristics in a theater or a hall.
[0002]
[Prior art]
The acoustic characteristics of a theater or a hall vary greatly depending on whether or not a spectator is seated in the auditorium. Therefore, in order to perform performance verification measurement and acoustic adjustment before completion for acoustic design targets such as theaters and halls, it is necessary to measure acoustic characteristics in a state where a person is seated in a passenger seat.
[0003]
Conventionally, a person is actually seated in the passenger seat portion and the acoustic characteristics are measured.
[0004]
However, in such a measurement method, noise generated by slight human movement and breathing hinders measurement, and there are limitations in terms of labor and cost, and there are limits to long-time measurement. there were.
[0005]
In order to solve such problems, a method has been proposed in which a doll (dummy sound absorber) imitating a person is installed in each seat and measured (see, for example, Patent Document 1).
[0006]
In addition, sound-absorbing curtains that have excellent sound-absorbing characteristics and can be installed suspended from a ceiling or the like are described in various documents (see, for example, Patent Document 2).
[0007]
[Patent Document 1]
JP-A-6-194219 [Patent Document 2]
Japanese Patent Laid-Open No. 8-42015
[Problems to be solved by the invention]
However, even in the method of measuring using dummy sound absorbers, the number of dummy sound absorbers equal to the actual number of seats must be arranged in each seat, which is very limited in terms of labor and cost. In addition, it takes a lot of burden to transport and store the dummy sound absorbers, and when changing the measurement conditions (number of placement, placement area, etc.), it takes time and effort to place and remove it. Is not realistic.
[0009]
The present invention has been made to solve the above-described problems, and an object thereof is to provide an acoustic characteristic measuring method and an acoustic characteristic measuring apparatus capable of measuring an acoustic characteristic of a space by simply simulating a seated state. And
[0010]
[Means for Solving the Problems]
In general, the sound absorption characteristics of a seat row where a person is actually seated are relatively low in the low frequency region of 125 to 250 Hz and relatively large in the high frequency region of 500 Hz to 1 kHz. Tend. On the other hand, the sound-absorbing force of a curtain having a certain size arranged with an air layer provided on the wall surface tends to show similar frequency characteristics.
[0011]
Therefore, the present inventors measured the acoustic characteristics by applying appropriate fabrics to the backrests so that an air layer is formed between the backrests of the chairs arranged adjacent to each other in the front-rear direction. Thus, the inventors have found that the above-described problems can be solved, and have made the present invention.
[0012]
That is, the acoustic characteristic measuring method of the present invention is an acoustic characteristic measuring method for measuring the acoustic characteristics of a space in which a plurality of chairs having a backrest are arranged adjacent to each other in the front-rear direction. A porous curtain-type sound absorbing member is hung over the plurality of backrests so that an air layer is formed between the backrest and the backrest of the chair, and a state where a person is seated on the chairs arranged adjacent to each other is simulated. A sound absorbing state is generated and the acoustic characteristics of the space are measured.
[0013]
The acoustic characteristic measuring apparatus of the present invention is an acoustic characteristic measuring apparatus that measures the acoustic characteristics of a space in which a plurality of chairs each having a backrest are arranged adjacent to each other in the front-rear direction. A sound absorption state simulating a state in which a person is seated on the chairs arranged adjacent to each other is generated by being hung on the plurality of backrests so that an air layer is formed between the backrest and the backrest of the chair. A porous curtain type sound absorbing member and a measuring means for measuring the acoustic characteristics of the space in the generated sound absorbing state are configured.
[0014]
The acoustic characteristic measuring method and the acoustic characteristic measuring apparatus according to the present invention provide air between a backrest and a backrest of the chairs arranged adjacent to each other in a space where the chairs provided with the backrest are arranged adjacent to each other in the front-rear direction. A porous curtain-type sound absorbing member is hung over a plurality of backrests so that a layer is formed. This generates a sound absorption state that simulates a state in which a person is seated on a plurality of chairs arranged adjacent to each other. In this state, the acoustic characteristics of the space are measured.
[0015]
As a result, it is possible to easily realize a sound absorption state that simulates the situation where a person is actually seated in a seat and measure the acoustic characteristics of a space such as a theater or a hall. The acoustic adjustment can be performed with high accuracy.
[0016]
In the present invention, noise that occurs when a person is actually seated does not occur, and measurement over a long period of time is possible. In addition, time, labor, and cost can be saved as compared with the method of arranging dummy dolls, and the measurement conditions (number of arrangements, arrangement areas, etc.) can be easily changed.
[0017]
The porous curtain type sound absorbing member is not particularly limited as long as it has a predetermined air permeability. For example, a woven fabric having an acoustic flow resistance representing a degree of air permeability of about 630 to 870 Pa · s / m can be used. The acoustic flow resistance Rf (Pa · s / m) is the difference between the small pressure difference ΔP (Pa) and the flow velocity v (m / s) generated on both sides of a sample placed in a steady air flow with uniform wind speed distribution. ) From the following equation.
[0018]
Rf = ΔP / v
By using such a porous curtain type sound absorbing member, it is possible to generate a sound absorbing state that is closer to a state in which a person is seated on a plurality of adjacently arranged chairs.
[0019]
The porous curtain type sound absorbing member of the present invention has an air layer between a backrest and a backrest of the chairs arranged adjacent to each other in a space where a plurality of chairs provided with the backrest are arranged adjacent to each other in the front-rear direction. By being hung on a plurality of backrests as it is formed, a sound absorbing state simulating a state in which a person is seated on a plurality of adjacent chairs is generated. The measuring means measures the acoustic characteristics of the space in the sound absorbing state generated by the porous curtain type sound absorbing member.
[0020]
Further, the porous curtain-type sound absorbing member of the present invention, the porous curtain-type sound absorbing member, and the porous curtain-type sound absorbing member in a state where the porous curtain-type sound absorbing member is hung on a backrest of a chair arranged in a plurality of adjacent positions. You may provide the tension | tensile_strength provision means which provides tension | tensile_strength type sound-absorbing members.
[0021]
In this way, by providing tension applying means for applying tension to the porous curtain type sound absorbing member, the porous curtain type sound absorbing member does not fall into the air layer when it is hung on the backrest of a plurality of adjacent chairs. An air layer can be formed between the backrests and the backrests of the chairs that can be held in a stretched state and are easily arranged adjacent to each other.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0023]
FIG. 1 is a diagram schematically showing an overall configuration of an acoustic characteristic measuring apparatus for measuring acoustic characteristics (here, reverberation time) of a hall 10 according to the present embodiment. The hall 10 is provided with a plurality of rows of seats 50 in which a plurality of chairs for spectators to sit are arranged adjacent to each other in the front-rear direction. In FIG. 1, only one row of seat rows 50 is shown for simplification.
[0024]
A woven fabric 40 is hung over the backs of a plurality of chairs adjacent to each other in the front-rear direction of the seat row 50. As a result, it is possible to generate a sound absorption state that simulates a state in which a person is actually seated in the seat row 50. In addition, the woven fabric 40 is comprised from the woven fabric main body 42 and the rod-shaped weight 44 so that it may mention later. Examples of physical properties of the woven fabric body 42 and how to hang the woven fabric 40 will be described later.
[0025]
Furthermore, a speaker 12 and a microphone 16 are provided as components of the acoustic characteristic measuring apparatus. The speaker 12 reproduces an electric signal as a sound wave. The microphone 16 collects sound waves and converts them into electric signals.
[0026]
A phase expansion pulse generator 14 is connected to the speaker 12. The phase stretching pulse generator 14 is a device for generating a measurement signal sound, and specifically generates a phase stretching pulse. The phase-stretching pulse is a continuous sweep of a wideband signal that is generated sequentially at different times from the low sound range to the high sound range. The speaker 12 reproduces the phase stretching pulse (electric signal) generated by the phase stretching pulse generator 14 as a sound wave.
[0027]
A recorder 18 is connected to the microphone 16. The recorder 18 records the electrical signal converted by the microphone 16 on the recording medium 20. The recording medium 20 is not particularly limited as long as it is a recording medium that can record an electric signal. For example, the recording medium 20 can be a recording medium such as DAT (digital audio tape).
[0028]
The acoustic characteristic measuring device further includes a regenerator 22, an A / D converter 24, a computer 26, and a reverberation time reading unit 36. These components do not need to be provided in the hall 10 and may be installed in a place away from the hall 10.
[0029]
The regenerator 22 reproduces the electrical signal (phase stretching pulse) recorded on the recording medium 20.
[0030]
The A / D converter 24 converts the electrical signal (phase stretching pulse) regenerated by the regenerator 22 from an analog signal to a digital signal.
[0031]
The computer 26 inputs a digital signal obtained by conversion by the A / D converter 24, performs a predetermined process, and outputs a reverberation waveform 34. Specifically, as shown in the figure, the functions of the phase compression calculation 28, the frequency filter 30, and the inverse square integration calculation 32 are executed. These functions are performed by executing a program stored in a storage device (not shown) of the computer 26 by a CPU (not shown) of the computer 26.
[0032]
The phase compression calculation 28 calculates a time difference due to the frequency component of the input phase stretch pulse at the same time, and obtains an impulse response.
[0033]
The frequency filter 30 divides the impulse response obtained by the phase compression calculation 28 for each constant frequency component to obtain a reflectogram waveform.
[0034]
The inverse square integration operation 32 performs inverse square integration of the reflectogram waveform, which is the frequency band component of the impulse response, obtained by the frequency filter 30 to obtain a reverberation waveform.
[0035]
The reverberation time reading unit 36 reads the reverberation time from the reverberation waveform 34 output from the computer 26. Note that the reverberation waveform output from the computer 26 may be printed on paper, and the reverberation time may be read manually from the printed reverberation waveform.
[0036]
The reverberation time of the hall 10 is measured by the acoustic characteristic measuring apparatus having such a configuration. There are various other methods for measuring the reverberation time, but any method may be used and the method is not limited to the method (apparatus) described above.
[0037]
FIG. 2 is a view showing an appearance of a chair constituting the woven fabric 40 and the seat row 50 and an image of a state in which the woven fabric 40 is installed in the seat row 50.
[0038]
As shown in the figure, the chairs 50 ₁ to 50 _n constituting the seat row 50 have a backrest 52 and a seat portion 54, and the chairs 50 ₁ to 50 _n are separated by a distance of about 90 to 100 cm in the front-rear direction. is set up.
[0039]
The woven fabric 40 includes a woven fabric main body 42 and a rod-shaped weight 44.
[0040]
The woven fabric main body 42 has an article-like shape having a width substantially the same as the width between the armrests on the outside of the two chairs arranged side by side, for example, a width of 910 mm.
[0041]
The rod-shaped weights 44 are provided at both ends of the woven fabric body 42, and when the woven fabric 40 is hung on the seat row 50, tension is applied to the woven fabric body 42 by its own weight.
[0042]
The woven fabric 40 is wound around one of the rod-shaped weights 44 so that the amount of the woven fabric 40 can be adjusted in accordance with the size of the seat row 50 in the front-rear direction. It is possible. Further, since the woven fabric main body 42 can be wound around the rod-like weight 44 and can be gathered together, it is easy to remove from the seat row 50 and is easy to handle and convenient for transportation and storage.
[0043]
Here, the physical properties of the woven fabric body 42 will be described in detail.
[0044]
The woven fabric body 42 used in the present embodiment is a porous curtain type sound absorbing member having a predetermined air permeability. For example, a woven fabric having an acoustic flow resistance of about 630 to 870 Pa · s / m can be used.
[0045]
The acoustic flow resistance is an amount representing the degree of air permeability of a porous material such as glass wool, cloth, paper, and the like, and is a physical property value that shows a high correlation with the sound absorption coefficient.
[0046]
The acoustic flow resistance Rf (Pa · s / m) is calculated from the small pressure difference ΔP (Pa) and flow velocity v (m / s) generated on both sides of a sample placed in a steady air flow with uniform wind speed distribution. It is obtained by the following formula.
[0047]
Rf = ΔP / v
Further, since the thickness and the cotton density of the woven fabric body 42 also affect the degree of air permeability, it is preferable to use the woven fabric body 42 having a thickness and a cotton density such that the acoustic flow resistance is as described above. For example, a material having a thickness of about 0.5 mm and a surface density of about 0.26 kg / m ² can be used.
[0048]
For this reason, the material used for the curtain or the like is appropriate as the material of the woven fabric body 42. As materials for curtain fabrics, rayon, cotton, acrylic, cupra, etc. are generally used in addition to polyester, and these are used alone or in combination. Therefore, these materials can also be used for the material of the woven fabric body 42.
[0049]
Therefore, as the woven fabric body 42 of the woven fabric 40 hung on the seat row 50, for example, the acoustic flow resistance value is about 630 to 870 Pa · s / m, the thickness is about 0.5 mm, and the surface density is about 0.26 kg / m ² . Polyester woven fabric generally used for curtains and the like can be used.
[0050]
A state in which such a woven fabric 40 is unfolded and hung over the backrests 52 of the chairs 50 ₁ to 50 _n for every two rows of non-sitting seats is shown in the drawing. Since the tension is applied to the woven fabric body 42 by the rod-like weight 44, the woven fabric main body 42 can maintain a tensioned state so as not to fall into the air layer.
[0051]
Accordingly, an air layer is formed by the backrests 52 and the seat portions 54 of the chairs 50 ₁ to 50 _n and the woven fabric body 42.
[0052]
In general, the sound absorption characteristics of a seat row where a person is actually seated are relatively low in the low frequency region of 125 to 250 Hz and relatively large in the high frequency region of 500 Hz to 1 kHz. Tend. By hanging the above-mentioned woven fabric 40 over the respective backrests 52 of the chairs in the seat row 50, substantially the same frequency characteristics are realized, and a sound absorption state simulating a state in which a person is seated on the seat row 50 can be generated. it can.
[0053]
In such a state, sound waves for measuring acoustic characteristics are reproduced from the speaker 12 installed in the hall 10. The sound waves are collected by the microphone 16 while being absorbed by the woven fabric 40 and the seat row 50, converted into an electric signal, and recorded on the medium 20 by the recording device 18.
[0054]
The electric signal recorded on the medium 20 is input to the computer 26 through the above-described regenerator 22 and A / D converter 24, and is subjected to predetermined processing by the computer 26 to output a reverberation waveform 34. The reverberation time is read from the reverberation waveform 34 by the reverberation time reading unit 36.
[0055]
The applicant of the present invention measured the reverberation time in two holes using the woven fabric 40 described above as a woven fabric that hangs on the seat row, and as a result, the measurement results as shown in FIGS. 3 and 4 were obtained.
[0056]
FIG. 3 is a diagram showing the reverberation time measurement results in Hall A having 759 seats (excluding 8 wheelchair spaces) and a room volume of 6800 m ³ .
[0057]
In this hall A, the reverberation time in the state where the person is actually seated and in the vacant seat state is measured, and the above-mentioned woven fabric 40 is hung on the seat row by the method shown in FIG. 2 to simulate the actual seated state. The reverberation time was measured by generating a sound absorption state.
[0058]
In the measurement in which a person was actually seated, 701 persons were seated and 15 measurers were seated. In addition, measuring devices such as speakers and microphones were installed in 20 of the vacant seats. For this reason, the seating rate was measured at 97% of the total number of seats.
[0059]
Further, in the simulated state, the measurement was performed by applying the woven fabric 40 to all the seat rows as shown in FIG.
[0060]
As is apparent from FIG. 3, the reverberation time measured in the simulated state and the reverberation time measured in the seated state show substantially the same value.
[0061]
In general, in the seated state, since there is a tendency to exhibit a relatively large sound absorption in the frequency range of 500 Hz to 1 kHz, the measurement result of the reverberation time in this frequency region is particularly important. As is apparent from the figure, the error in the reverberation time between the actual seating state and the simulated sound absorption state in this frequency region is relatively small, and it can be seen that the measurement result almost the same as the actual seating state can be obtained.
[0062]
FIG. 4 is a diagram showing the reverberation time measurement results in Hall B, which has 1810 seats and a room volume of 14500 m ³ .
[0063]
In Hall B, as in Hall A, the reverberation time in the actual seated and unoccupied state is measured, and the woven fabric 40 is applied to the seat row by the method shown in FIG. The reverberation time was measured by generating a sound-absorbing state simulating the seated state.
[0064]
In the measurement where people were actually seated, the exact number of seats was not recorded, but the measurement was performed with the same seating rate as in Hall A.
[0065]
As is apparent from the figure, the reverberation time measured in the simulated state and the reverberation time measured in the seated state show substantially the same value. Also, it can be seen that the reverberation time error in the frequency range of 500 Hz to 1 kHz is relatively small within 0.1 seconds, and the measurement result is almost the same as the actual seated state.
[0066]
As described above, in the hall 10 having the plurality of seat rows 50 in which the chairs 50 ₁ to 50 _n are arranged adjacent to each other in the front-rear direction, the back 52 and the back 52 of the chairs 50 ₁ to 50 _n in the seat row 50 are provided. A woven fabric 40 is hung over a plurality of backrests 52 so that an air layer is formed between them, and a sound absorption state simulating the state of being seated on the seat row 50 is generated, and the acoustic characteristics (reverberation time) of the hall 10 are obtained. Since the measurement is performed, the acoustic characteristics can be measured in the sound absorption state equivalent to the sound absorption state in the actual seating state. Thereby, the acoustic adjustment before completion with respect to the acoustic design targets such as a theater and a hall can be performed with high accuracy. Also, during rehearsal, the difference in acoustic characteristics from the actual performance can be easily eliminated, and it can also be used for acoustic adjustment during theater / hall operation.
[0067]
In the above-described embodiment, an example in which the reverberation time is measured by simulating a state where a person is seated in all the seat rows has been described. However, the measurement conditions (the number and area of the seat rows on which the woven fabric 40 is hung) are changed. Can also be measured. As described above, since the woven fabric 40 is easy to install and remove, the measurement conditions can be easily changed as compared with a method in which a person is actually seated or a dummy sound absorber is arranged.
[0068]
Further, the above-described embodiment shows an example of the present invention and does not limit the configuration of the present invention.
[0069]
【The invention's effect】
As described above, according to the present invention, by applying a porous curtain type sound absorbing member over a plurality of backrests so that an air layer is formed between the backrests of the chairs arranged adjacent to each other. The acoustic characteristics are measured by generating a sound absorption characteristic that simulates the seating state of the user, so that the acoustic characteristic can be easily measured in a sound absorption state equivalent to the sound absorption state in the seated state. Play.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing an overall configuration of an acoustic characteristic measuring apparatus for measuring acoustic characteristics of a hole according to the present embodiment.
FIG. 2 is a view showing an appearance of a chair constituting the woven fabric 40 and the seat row 50 and an image of a state in which the woven fabric 40 is installed in the seat row 50.
FIG. 3 is a diagram illustrating a reverberation time measurement result in Hall A;
FIG. 4 is a diagram illustrating a reverberation time measurement result in Hall B;
[Explanation of symbols]
10 Hall 12 Speaker 14 Phase Stretching Pulse Generator 16 Microphone 18 Sound Recorder 20 Recording Media 22 Regenerator 24 A / D Converter 26 Computer 36 Reverberation Time Reading Unit 40 Woven Fabric 42 Woven Fabric Main Body 44 Bar Weight 50 Seat Row 50 _{1 to} 51 _n Chair 52 Backrest 54 Seat

Claims (3)

An acoustic characteristic measurement method for measuring acoustic characteristics of a space in which a plurality of chairs with a backrest are arranged adjacent to each other in the front-rear direction,
A porous curtain type sound absorbing member is hung over the plurality of backrests so that an air layer is formed between the backrests and the backrests of the plurality of adjacent chairs. An acoustic characteristic measurement method for measuring an acoustic characteristic of the space by generating a sound absorption state that simulates a state in which a person is seated. An acoustic characteristic measuring device that measures acoustic characteristics of a space in which a plurality of chairs with a backrest are arranged adjacent to each other in the front-rear direction,
A state in which a person is seated on the plurality of adjacently arranged chairs by being hung on the plurality of backrests so that an air layer is formed between the backrests and the backrests of the adjacently arranged chairs. A porous curtain type sound absorbing member that generates a sound absorbing state simulating
Measuring means for measuring acoustic characteristics of the space in the generated sound absorption state;
A device for measuring acoustic characteristics. Tension applying means for applying tension to the porous curtain-type sound absorbing member in a state where the porous curtain-type sound absorbing member is hung on a backrest of a chair in which the plurality of adjacent porous curtain-type sound absorbing members are arranged adjacent to each other. The acoustic characteristic measuring device according to claim 2 provided.

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