JP2010256847A - Sound adjusting method, sound adjusting program, sound field adjusting system, loudspeaker stand, and furniture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sound adjusting method by which feeling of spread more than a space of a sound chamber is obtained. <P>SOLUTION: In the sound adjusting method, a non-sound section of direct sound and initial reflection sound (primary reflective sound from a floor, a wall and a ceiling etc.) is compensated by a spread reflection sound. The spread reflection sound is generated by arranging a scattered reflection object at a side of a sound source. The scattered reflection object has a structure with a gap, in which multi-layer scattered reflection occurs. Density of spread sound becomes higher as the scattered reflection object is positioned away from a sound source and/or sound reception. Thus, it is arranged so that the spread reflection sound may be generated in the non-sound section. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an acoustic adjustment method, an acoustic adjustment program, a sound field adjustment system, a speaker stand, and furniture, and in particular, an acoustic adjustment method, an acoustic adjustment program, a sound field adjustment system, and a speaker for obtaining a good sound field in various acoustic rooms. The table and furniture.

Conventionally, it has been difficult to obtain a good sound field in various acoustic rooms such as an audio room and an audio visual room in a normal house due to limitations in size and design.
Referring to the side view of FIG. 6 and the plan view of FIG. 7, each drawing shows the direct sound and the initial reflected sound (primary reflected sound from the floor, wall, ceiling, etc.) in the sound field of these acoustic rooms. ).
Sound waves generated from the speaker P (sound generator) in FIGS. 6 and 7 reach the listener L as direct sound 200. The sound waves emitted from the speaker P are reflected to the listener L in addition to the ceiling reflected sound 320 that is the primary reflected sound reflected on the ceiling, the floor reflected sound 330 that is similarly reflected on the floor, and the left and right side walls as well. A side wall reflected sound 350, a front wall reflected sound 310 that is a primary reflected sound that is reflected from the bass reflex port and reflected on the front wall of the listener L, and a rear wall reflected sound 340 that is similarly reflected on the rear wall of the listener L. A sound wave called an early reflection sound arrives. In addition, there is a sound wave called a reverberant sound that reaches the listener L while the reflected sound is further reflected and attenuated by the room wall.
The relationship between these sound waves will be described with reference to FIG.
First, the initial reflected sound 300 reaches the direct sound 200 having the highest sound pressure over a long distance by reflection. For this reason, it arrives later than the direct sound in time. Furthermore, the reverberant sound 400 that has been reflected multiple times arrives.

The listener L can listen to these sound waves and consciously and unconsciously recognize the acoustic environment of the acoustic rooms, that is, the sound field.
Therefore, the listener L may feel the narrowness of the acoustic rooms due to the intensity and direction of the initial reflected sound, the amount of reverberant sound, and the like.
Therefore, in order to obtain a good sound field, it is important to adjust the initial reflected sound and the reverberant sound so that the sound spread can be felt even in a room with a finite volume.
For this reason, conventionally, acoustic panels made of a sound absorbing material that is placed in a room or attached to a wall or ceiling in order to adjust the sound in the room are commercially available.

Here, as a conventional acoustic panel, referring to Patent Document 1, an acoustic diffusion panel that can easily adjust the sound environment in the horizontal direction is described (hereinafter referred to as Conventional Technique 1).
The acoustic panel of prior art 1 includes two support legs that are erected at regular intervals, and two acoustic panels that are supported by the respective support legs. This acoustic panel is connected so that two acoustic panels can be freely opened in the horizontal direction. Each acoustic panel is supported by a support leg via a slide mechanism that slides in the horizontal direction, and a rotation mechanism that rotates the acoustic panel in the horizontal direction is provided on each support leg. A working surface that reflects or absorbs sound is formed on the front surface of the acoustic panel, and the acoustic panel is supported by the support legs on the rear surface.
By using the acoustic panel of prior art 1, it is possible to finely adjust the direction of sound absorption and reflection by opening and closing the acoustic panel like a folding screen, and the acoustic panel is supported via a slide mechanism and a rotation mechanism. Since it is supported by the legs, it can be opened and closed smoothly.
Therefore, the sound field of the acoustic rooms can be improved by adjusting the initial reflected sound and the reverberant sound. Further, it is possible to reduce multi-next-time reflection (flutter echo), standing wave, wall vibration, and the like that occur between opposing wall surfaces in the room.

JP 2007-291804 A

However, referring to FIG. 8, the acoustic panel of the related art 1 can absorb and adjust the magnitude of the initial reflected sound and the reverberant sound. However, when the initial reflected sound and the reverberant sound are absorbed, the listener In some cases, the sound field seems to be unnatural and the sound field feels uncomfortable.
In addition, although the acoustic panel of the prior art 1 can slightly adjust the time delay by changing the direction of reflection, there is a time difference between the direct sound and the initial reflected sound. There was a problem that it was difficult to make the sound spread more than that.

  This invention is made | formed in view of such a condition, and makes it a subject to eliminate the above-mentioned subject.

The acoustic adjustment method of the present invention is an acoustic adjustment method for adjusting the sound field of various acoustic rooms, and generates diffuse reflection sound in a section between a direct sound that reaches a receiving point from a sound source and an initial reflection sound. It is characterized by making it.
The acoustic adjustment method of the present invention is further characterized in that diffuse reflected sound is generated also in the section of the initial reflected sound.
In the acoustic adjustment method of the present invention, the diffuse reflected sound is generated by disposing a diffuse reflector on the sound source and / or sound receiving point side, and the diffuse reflector has a structure that performs multilayer diffuse reflection with a gap, The diffuse reflector is arranged so that its density increases as the distance from the sound source and / or sound reception increases, and the diffuse reflection sound is generated between the sections.
The acoustic adjustment method of the present invention is characterized in that the irregular reflectors are randomly arranged.
The acoustic adjustment method according to the present invention is characterized in that the irregular reflector is a columnar diffuser having an approximately circular cylinder, an approximately rectangular column, or an approximately elliptical column, each having a different diameter.
The acoustic adjustment method of the present invention is characterized in that the columnar diffuser is skewered.
The acoustic adjustment method of the present invention is characterized in that the diffuse reflector is any one of a spherical shape, an elliptical spherical shape, and a skewered shape of an uneven object.
The acoustic adjustment program of the present invention is an acoustic adjustment program for executing the acoustic adjustment method on a computer.
The sound field adjustment system according to the present invention is a sound field adjustment system including the computer that executes the sound adjustment program.
The speaker stand according to the present invention is characterized in that the arrangement of the irregular reflectors is calculated by the acoustic adjustment method.
The furniture of the present invention is characterized in that the arrangement of the irregular reflectors is calculated by the acoustic adjustment method.

  ADVANTAGE OF THE INVENTION According to this invention, the acoustic adjustment method which produces the sound field of a favorable acoustic room can be provided by producing a diffuse reflection sound effectively between a direct sound and an early reflection sound.

It is a control block diagram of the acoustic adjustment system X which concerns on the 1st Embodiment of this invention. It is a flowchart which concerns on operation | movement of the acoustic adjustment system X which concerns on the 1st Embodiment of this invention. It is a conceptual diagram when the acoustic diffuser which concerns on the 1st Embodiment of this invention generate | occur | produces a diffuse reflection sound. It is a conceptual diagram which concerns on the plane at the time of arrange | positioning an acoustic diffuser in acoustic rooms by the acoustic adjustment method which concerns on the 1st Embodiment of this invention. Relationship between direct sound, diffuse reflected sound, primary reflected sound, reverberant sound and time decay when an acoustic diffuser is placed in various acoustic rooms by the acoustic adjustment method according to the first embodiment of the present invention It is a graph which shows. It is the conceptual diagram which concerns on the side of an acoustic room about the relationship between the direct sound and the initial reflection sound in the conventional acoustic rooms. It is the conceptual diagram which concerns on the plane of an acoustic room about the relationship between the direct sound and the initial reflection sound in the conventional acoustic rooms. It is a graph which shows the relationship between the direct sound in a conventional acoustic room, a primary reflected sound, a reverberation sound, and time decay. It is a conceptual diagram which concerns on the side of the acoustic rooms which have arrange | positioned the speaker stand 60 in the acoustic rooms which concern on the 2nd Embodiment of this invention. It is a flowchart which concerns on operation | movement of the acoustic adjustment system X which concerns on the 2nd Embodiment of this invention. It is a conceptual diagram which concerns on the plane at the time of arrange | positioning an acoustic diffuser to the speaker stand 60 which concerns on the 2nd Embodiment of this invention.

<First Embodiment>
〔System configuration〕
With reference to FIG. 1, the control configuration of the acoustic adjustment system X according to the first embodiment of the present invention will be described.
The acoustic adjustment system X mainly includes a PC 10, a sound field measuring unit 20, an input device 30, a display unit 40, a printer 50, and the like.
The PC 10 is a normal PC / AT compatible machine, which is a PC (personal computer), or a PC with a MAC standard, and is a component that can perform the calculation of the acoustic adjustment method according to the first embodiment of the present invention. is there. The PC 10 calculates an input unit 110 (input unit) for inputting various data, a storage unit 120 (storage unit) for storing the input data, arrangement data for the acoustic diffuser, and the like, and a diameter of the acoustic diffuser described later. A time calculation unit 130 (diameter calculation means) that is an arithmetic unit for the purpose, an arrangement calculation unit 140 (output value calculation means) that is an arithmetic unit or the like for calculating the arrangement condition of the acoustic diffuser, and a CPU (central processing unit). A control unit 150 such as a unit, a central processing unit (MPU) or an MPU (micro processing unit), and an output unit 160 that outputs a result calculated by calculation are mainly included.
The sound field measuring unit 20 is a device for measuring the indoor sound field including, for example, a directional sound wave generator and a microphone, and acquires data on reflected sound and sound field properties in the room using ultrasonic waves or the like. it can. Thereby, data about the relationship between the direct sound and the temporarily reflected sound can be obtained.
The input device 30 is a component relating to a user interface such as a keyboard, a pointing device such as a mouse, and a touch panel.
The display unit 40 is a display device such as a general LCD display, a plasma display, or an organic EL (electroluminescence) display. The display unit 40 may display the room structure in a three-dimensional manner using a liquid crystal shutter method, a hologram method, or the like.
The printer 50 is a printing device such as a general printer or an XY plotter. Further, the printer 50 may be provided with a flash memory card reader / writer or the like so as to be able to store data such as design drawings and arrangement of acoustic diffusers.

[Configuration of PC 10]
The PC 10 will be described more specifically.
The input unit 110 includes a sound field measurement unit 20, an input device 30, and other devices (not shown), such as a LAN, a WAN, a flash memory card reader, and an input unit such as a DVD-ROM. Various terminals such as serial and parallel and I / O. The input unit 110 can input data such as the sound fields and shapes of the acoustic rooms from the sound field measuring unit 20 and data such as the shapes of the acoustic rooms set in advance by a measurer.
The storage unit 120 is a RAM, a ROM, a flash memory, an HDD (hard disk drive), or the like. The storage unit 120 stores data such as sound fields and shapes of acoustic rooms, an acoustic adjustment program for executing the acoustic adjustment method according to the first embodiment of the present invention, and other data necessary for the acoustic adjustment program. To do.
The time calculation unit 130 is a calculation unit such as a dedicated calculation DSP (digital signal processor), a calculation unit dedicated to physical calculation, or a GPU (Graphics Processing Unit), and directly from the data of the sound field measurement unit 20 to be described later. The time between the sound 200 and the initial reflected sound 300 is calculated.
The arrangement calculation unit 140 is a computing unit capable of computing in real time, such as a dedicated computing DSP, a physical computing dedicated computing device, or a GPU. The arrangement calculation unit 140 calculates an optimum arrangement condition of the acoustic diffuser for putting the diffuse reflection sound 360 into the time between the direct sound 200 and the initial reflection sound 300 described later.
The control unit 150 is a part that performs control and calculation when actually performing the following noise determination processing. The control unit 150 executes various control and calculation processes according to programs stored in the ROM, HDD, or the like of the storage unit 120.
The output unit 160 is an I / O that outputs to an output unit such as the display unit 40 or the printer 50. The output unit 160 can output the structure and design drawing of the designed acoustic rooms. Moreover, it can output also about the design of the acoustic diffuser structure etc. which are the diameter and arrangement | positioning conditions of an acoustic diffuser. The output unit 160 also includes an audio I / O, and it is also possible to simulate and output an actual way of hearing sounds in a simulation described later.
Note that the functions of the time calculation unit 130 and the arrangement calculation unit 140 may be realized using the calculation function of the control unit 150.

[Sound adjustment method]
Here, an outline of the acoustic adjustment method according to the first embodiment of the present invention is described with reference to FIGS.
As described above, in various acoustic rooms that must be created in a limited space, the space behind the speaker P for construction is limited. For this reason, conventionally, with respect to various acoustic rooms, the sound field adjustment by acoustic design and construction is performed, or the acoustic panel is combined to adjust the magnitude of the initial reflected sound and the reverberant sound and the time delay.
Conventionally, in such an adjustment method, it has been empirically difficult to adjust the sound field so as to feel the extent of the acoustic rooms.

For this reason, the inventors of the present invention diligently studied and experimented on a method for adjusting the sound field so that it can be more spacious in various acoustic rooms.
The inventors of the present invention have conventionally considered that a silent portion formed between a direct sound and an initial reflected sound (primary reflected sound from a floor, a wall, a ceiling, etc.) contributes to the sound spread of acoustic rooms. I found that it had a bigger impact than it was.
That is, conventionally, there is always a silent section between the direct sound and the initial reflected sound, and the listener can detect this silent section consciously and unconsciously. The listener can consciously and unconsciously grasp the size of the acoustic rooms based on the length of the silent section.
Therefore, it has been found that it is difficult to adjust the sound field so that the sound rooms are larger than the size of the acoustic rooms.
For this reason, the inventors of the present invention have invented a sound field adjustment method for performing an adjustment to create a diffuse reflection sound (multilayer diffuse sound) in a silent section between a direct sound and an initial reflection sound.
Thereby, the feeling of sound spread in the acoustic rooms can be greatly improved.

As described above, the inventors of the present invention have come up with a sound field adjustment method that compensates for a silent portion formed between a direct sound and an initial reflected sound with a diffuse reflected sound.
For this reason, the inventors of the present invention diligently conducted experiments and examinations. As a result, such a multilayer diffused reflection structure is not limited to the acoustic panel as in the prior art 1, the plate-like acoustic panel, and the uneven acoustic panel. Then it was difficult to realize.
Accordingly, the inventors of the present invention have come up with the idea of using a multilayer irregular reflection structure in order to generate this diffuse reflection sound. As such a columnar diffuser (columnar diffused sound absorber, columnar reflector), a plurality of columns having different diameters are randomly arranged (for example, https://www.noe.co.jp/product). / Pdt1 / pd1 — 12.html)).
This columnar diffuser can effectively give a sense of sound spread to various acoustic rooms even in a normal arrangement. At this time, although some diffuse reflection sounds are generated between the direct sound and the initial reflection sound, the arrangement has been changed empirically so as to give a sense of sound spread as much as possible. .

For this reason, the inventors of the present invention have conducted intensive experiments on a method for configuring and arranging the columnar diffuser so that a diffuse reflection sound is generated in a silent section formed between the direct sound and the initial reflection sound. And the acoustic adjustment method according to the first embodiment of the present invention has been completed.
In the acoustic adjustment method according to the first embodiment of the present invention, a multi-layer diffuse reflection structure is configured by ensuring a gap between objects that contributes to diffusion based on a reference as described later.
This multi-layer diffuse reflection structure generates a diffuse reflection sound that fills the section between the direct sound and the initial reflection sound that accompanies the direct sound reproduced from the speaker, thereby limiting the size of the acoustic rooms. It is possible to achieve a sound spread beyond

Originally, the primary reflected sound has the effect of making the room feel the sound of the direct sound. However, there is a problem that the primary reflected sound interferes with the direct sound.
That is, when the phase of the primary reflected sound is the same, the sound pressure is doubled, and can be increased by about 6 dB, for example. However, when the phase is reversed, the sound pressure becomes infinitely zero. For this reason, there is a problem that if there is a primary reflected sound with high intensity, the frequency characteristics of the combined waveform of the direct sound and the primary reflected sound become extremely uneven characteristics.
In the acoustic adjustment method according to the first embodiment of the present invention, in addition to the silent section between the direct sound and the initial reflected sound, the initial reflected sound section including a plurality of incoming primary reflected sounds is also included. Diffuse reflection sound can be generated.
Thereby, an effect that extreme phase interference hardly occurs can be obtained.
In addition, the diffuse reflection sound generated in the silence interval between the direct sound and the initial reflection sound is also reflected by the wall to become a reflection sound. Therefore, the direct reflection sound is combined with the diffuse reflection sound in the primary reflection interval. And the frequency characteristics of the synthesized waveform of the primary reflected sound can be improved, and the sound field of the acoustic rooms can be greatly improved.

Referring to FIG. 3, there is shown an example in which a plurality of acoustic diffusers 500 (eg, columnar diffusers) that are irregular reflectors are arranged as an acoustic diffuser group 550 having a multilayer diffusion structure as shown in the figure.
Here, a direct sound 200 is generated from a speaker P such as a general dynamic type, electrostatic type or piezoelectric type speaker (loud speaker).
With respect to the direct sound 200, in the high sound band (high frequency, about several thousand Hz or higher), acoustic energy having a sharp directivity is radiated from the speaker P almost to the front.
However, in the mid-sound band (mid-sound range, about 500 Hz to about 2000 Hz), the sound energy of -5 to -15 dB from the direct sound 200 is radiated as the diffracted sound 355 in the 90 ° transverse direction with respect to the front of the speaker P. The
Further, in the low frequency band (low frequency range, about 300 Hz or less), acoustic energy is radiated almost omnidirectionally regardless of the direct sound 200 and the diffracted sound 355.
Therefore, conventionally, acoustic energy other than the direct sound 200 particularly in the mid-low range is reflected as it is by the wall or the acoustic panel and becomes a part of the initial reflected sound. Further, even when an acoustic panel is placed behind the speaker P, the delay of the initial reflected sound can only be adjusted, and the multilayer diffusion structure cannot be sufficiently achieved.
For this reason, the acoustic adjustment method according to the first embodiment of the present invention is characterized in that the acoustic diffuser 500 is disposed in the vicinity of the speaker P.
The acoustic diffuser 500 arranged in the vicinity of the speaker P does not radiate acoustic energy other than the direct sound 200 so as to become a partial component of the primary reflected sound as in the conventional case, and the diffuse reflected sound 360 is obtained. Can radiate.
Here, “diffusion” such as diffuse reflection 360 means that the reflection direction and / or reflection time delay (phase) of sound waves having different frequency bands are reflected so complexly that the listener L cannot recognize, that is, randomly reflected. Say.

Referring to FIGS. 4 and 5, there is shown an example when the diffuse reflection sound 360 described above reaches the listeners in the acoustic rooms.
As shown in FIG. 4, the diffuse reflected sound 360 reaches the listener L along with the direct sound 200 while maintaining a predetermined spread. Due to the configuration and arrangement of the acoustic diffuser 500 in the acoustic diffuser group 550 by processing described later, the diffuse reflected sound 360 is just the direct sound 200 and the initial reflected sound 300 such as the front wall reflected sound 310 and the rear wall reflected sound 340. The listener L is reached in the interval between
As a result, the direct sound 200 can be enriched particularly in the mid-low range. An example in which this diffuse reflection sound is added is shown in FIG.
Note that, here, the case where the number of speakers P is one has been described for the sake of simplicity, but in the case of a stereo system, two similar speakers P can be arranged side by side. Further, it is possible to support a multi-channel system such as a surround system.

[Sound adjustment method processing]
Here, the acoustic adjustment method according to the first embodiment of the present invention will be specifically described with reference to FIG.
As described above, in the acoustic adjustment method according to the first embodiment of the present invention, the diffused sound 360 is generated between the direct sound 200 and the initial reflected sound 300 so that the diffuse reflected sound 360 is generated. Calculate configuration and placement.
With regard to this configuration and arrangement, irregular reflectors (acoustic diffusers) that are not necessarily columnar for performing acoustic diffusion are in a multilayered state with gaps, and the average density as they move away from the sound source and / or sound receiving coordinates Use an increasing arrangement method. The increase in density is obtained by calculating the average value of the gaps between objects that contribute to diffusion in accordance with the acoustics of the acoustic rooms. Thereby, a multilayer diffusion structure can be realized. Further, the columnar diffuser may be fixed to a plate with a hole or the like and arranged in a skewered shape. Thereby, the effect that manufacture and arrangement | positioning of a columnar diffuser become easy is acquired.
As the irregular reflector, an example of using a columnar diffuser will be described below. However, any irregular structure such as a spherical shape, an elliptical spherical shape, a skewered shape of an uneven object, or the like can be used. A shaped irregular reflector may be used.
A specific process will be described below with reference to FIG. These processes are performed while the control unit 150 of the PC 10 controls each unit in accordance with a program stored in the storage unit 120.

(Step S101)
First, the sound field measurement unit 20 of the PC 10 performs sound field measurement processing.
Specifically, the sound field measuring unit 20 emits sound waves of a predetermined frequency from a speaker or the like (not shown), measures the sound waves with a microphone or the like, and determines the properties of the initial reflected sound 300 of the acoustic rooms and the reverberant sound. Measure acoustic characteristics such as size.
Also, acoustic characteristics can be calculated by performing simulation calculation based on information such as 3D scanner, shape data of acoustic rooms, and arrangement of acoustic panels.
In particular, by using a design drawing of various acoustic rooms, it is possible to adjust the diffuse sound similarly by a numerical calculation simulation.

(Step S102)
Next, the time calculation unit 130 of the PC 10 performs an arrival time calculation process.
In this step, an interval from the arrival of the direct sound 200 to the arrival of the initial reflected sound 300 is obtained from the acoustic characteristics described above. This interval can also be calculated in units of several milliseconds between the peak of acoustic energy measured as the direct sound 200 and the peak of acoustic energy measured as the initial reflected sound 300.
In the case of simulation by numerical calculation, for example, the peak of acoustic energy measured as the direct sound 200 according to the sound speed in the atmosphere at 25 ° C., the arrangement state of the speaker P, and the distance from the wall, The peak of the acoustic energy of the initial reflected sound 300 is obtained. As a result, a silent section between the direct sound 200 and the initial reflected sound 300 can be obtained by calculation.
As a result, a section in which the diffuse reflection sound 360 should be generated can be calculated.

(Step S103)
Next, the arrangement calculation unit 140 of the PC 10 performs arrangement condition calculation processing.
Here, an example in which the above-described irregular reflector is a columnar diffuser will be described.
If the cross-sectional shape of the columnar diffuser is a cylinder, a sound wave having a short wavelength can be re-radiated almost ideally at a predetermined ratio with respect to the diameter. Thereby, a uniform diffused sound can be returned to a wider area. Further, the cross-sectional shape may be an elliptical column or another shape in addition to the cylinder.
As the diameter of the columnar diffuser, since analysis when a sound wave is incident on a cylinder has been conventionally performed, this can be used (for example, acoustic engineering theory, “http: //www.acoust. rise.waseda.ac.jp/publications/onkyo/genron-4.pdf ").

On this basis, for the columnar diffuser group using a plurality of columnar diffusers, the number of columnar diffusers, the interval within the column, the interval between the columns, and the like are calculated. About this calculation, each density can be calculated and used as a reference for a cross-sectional area of a cross section cut by a plane perpendicular to the length direction of a plurality of columns. It is also possible to calculate the density (aperture ratio) of the cross-sectional area of the gap where the facing surface can be seen when the cross section perpendicular to the column length direction of the columnar diffuser is projected for each column of the acoustic diffuser. it can. The number of columns and the interval between columns can be set so that the difference in cross-sectional area is less than 10%.
This is equivalent to setting the value of the mean free path d in each column to a substantially constant ratio.
The mean free path d in the diffusion of the acoustic diffuser is described in more detail with the following formula:

As shown in this equation, the irregular reflectors are arranged so that the density increases as the mean free path d in each row is moved away from the sound source and / or the sound receiving point which is the coordinates of the listener L. In this example, an acoustic diffuser 500 that is a columnar diffuser is disposed. In other words, each acoustic diffuser 500 is in a multilayer or multiple state with a gap, and is arranged so that the density reflected by the back increases. In addition, as described above, when the diffuse reflector is a columnar diffuser, by increasing the cross-sectional area occupied by the thick-diameter column in the direction away from it, the high sound is diffusely reflected and the low sound is transmitted and reflected behind. Is possible.
Regarding the arrangement of the irregular reflectors and the value of the mean free path d, the mean free path d is determined by the direct sound according to the sound speed in the atmosphere at an air temperature of 25 ° C., the arrangement state of the speaker P, and the distance from the wall. A distance that reaches the listener L is set between 200 and the initial reflected sound 300. At this time, if the sound is too far from the speaker P, the diffracted sound 355 becomes an initial reflected sound, and therefore the arrangement calculation unit 140 can calculate and obtain it so as to approach the optimum distance.
Further, the interval between the irregular reflectors is set so that the columns calculated by the above equation (1) are arranged at random intervals. At this time, it is possible to randomly arrange 5 to 50% using random numbers with respect to the interval value in the case of uniform arrangement.
It is also possible to calculate so as to obtain a broadband frequency characteristic according to the acoustic characteristics of the acoustic rooms.

The arrangement of the sound absorbing layer can be further calculated to adjust the degree of the initial reflected sound and the reverberant sound so that a sense of spread can be obtained.
In the above method, the columnar diffuser (columnar reflector) has been described as the diffuse reflector. However, the present invention is not limited to this, and the density of the diffuse reflector increases as the distance from the sound source and / or sound receiving point increases. Any acoustic diffuser can be used in such an arrangement.
In addition, when the columnar diffuser is fixed to a plate with a hole and arranged in a skewered manner, the influence of sound by the fixed plate can also be calculated.
It is also possible to adjust the arrangement of the acoustic diffuser in consideration of the angle between the speaker P and the walls of the acoustic rooms.

Further, depending on the settings stored in the storage unit 120, the diffuse reflected sound can be added to the initial reflected sound 300.
As this setting, when the diffuse reflected sound is always added to the initial reflected sound 300, and when the frequency characteristic of the initial reflected sound is not so flat due to the sound field state in step S101 described above, the diffuse reflected sound is also reflected on the initial reflected sound 300 Can be set when adding sound.

Furthermore, a configuration in which diffuse reflection sound is added by reproducing sound is also possible. In this case, one to a plurality of other sub-speakers are arranged around the speaker P, and diffuse reflected sound is calculated, reproduced, and added. At this time, it is possible to reduce the initial reflected sound by calculating and adding a sound whose phase is opposite to that of the initial reflected sound.
Further, the sound reproduced from the speaker P can be configured to add diffuse reflection sound directly to the section between the direct sound 200 and the initial reflected sound 300 using a device such as a digital delay.
Furthermore, in the case of multi-channel reproduction, for example, it is possible to reproduce diffuse reflection sound from each speaker so as to reach the listener L in the section between the direct sound 200 and the initial reflected sound 300. . At this time, it is possible to calculate and add / reproduce the optimum diffuse reflection sound based on the arrangement of the surround speakers such as the front and rear, the center speaker, the distance from the listener L, and the like.

In the first embodiment described above, the acoustic diffuser 500 is disposed on the speaker P side, but a configuration in which the acoustic diffuser 500 is disposed near the sound receiving point is also possible.
For example, when the sound receiving point where the listener L is located is fixed, by arranging in this way, the section between the direct sound and the initial reflected sound is used regardless of the sound field of the room. And it can also be added in the subsequent section.
Further, by disposing the acoustic diffuser 500 near the sound receiving point, not only the direct diffracted sound 355 but also the diffuse reflected sound can be added to the direct sound, so that the sound field can be further expanded. it can.

The process of the sound adjustment method is thus completed.
The designer / enforcer of the acoustic rooms can arrange the acoustic diffuser around the speaker P with the calculated configuration and arrangement.

With the configuration described above, the following effects can be obtained.
In the sound field adjustment method according to the first embodiment of the present invention, a diffuse reflection sound can be generated between a direct sound and an initial reflection sound, not a simple acoustic panel for sound absorption.
For this reason, it becomes possible to give a feeling of depth to the reproduced sound from the speaker P beyond the size of the acoustic rooms. That is, the effect of enriching the sound generated from the sound source can be expected.
This is because the diffuse reflection sound (multilayer scattering sound) is added, so that the listener does not consciously and unconsciously grasp the size of the acoustic rooms due to the interval between the direct sound and the initial reflection sound. it is conceivable that. It is also considered that there is an effect of suppressing the primary reflected sound from the left and right sides of the room.
Further, it is considered that the reflection sound of the diffuse reflection sound further adds a reflection sound and a reverberation sound other than the sound field colored by the size of the original room, thereby enriching the sound field.
For this reason, in the sound field adjustment method according to the first embodiment of the present invention, an effect that the sense of depth of sound is improved during stereo reproduction is obtained.
Further, in the case of multi-channel playback, there is an effect that the “sound connection” of each channel feeling is improved.

Further, although the reproduced sound of the speaker P originally includes the early reflection sound and reverberation sound of the hall at the time of recording, it is considered that the listener has preferentially felt the sound field of the room.
In contrast, in the sound field adjustment method according to the first embodiment of the present invention, the influence of the sound field in the room is reduced by putting diffuse reflection sound in the section between the direct sound and the initial reflection sound. Thus, it is possible to feel the early reflection sound and reverberation sound included in the original reproduction sound.
For this reason, the effect that the sense of reality of the sound source recorded in a magnificent hall such as classical music is improved can be obtained.
In addition, since it is difficult to feel the sound accompanying the extra sound field in the room, there is an effect that it is less likely to get tired even when viewing at a high volume.

Further, in the acoustic adjustment method according to the first embodiment of the present invention, the diffuse reflector is in a multilayer state with a gap around the speaker P, and the density of the diffuse reflector increases as the distance from the sound source and / or the sound receiving point increases. The configuration and arrangement of the acoustic diffuser can be arranged to use increasing arrangement methods.
This eliminates the need for a special electrical device, and allows the sound fields of the acoustic rooms to be adjusted at low cost so that the sound is adjusted and feels spacious. In addition, since the existing acoustic rooms are not particularly renovated, the cost can be reduced.

As described above, in the sound field adjustment method according to the first embodiment of the present invention, the structure and arrangement of an acoustic diffuser can be provided in existing acoustic rooms.
In addition to this, it is of course possible to use it for acoustic rooms (for example, see “http://www.noe.co.jp/product/pdt1/pd1 — 12.html”) in which a conventional columnar diffuser is arranged. is there.
The columnar diffuser used in the first embodiment of the present invention provides a feeling that a plurality of reflectors / diffusers are arranged like a forest, for example, and the initial reflected sound is diffused sound. Reach the listener. For this reason, by using a diffuse reflector having a configuration and arrangement that generates diffuse reflection sound between the direct sound and the diffuse early reflection sound, it is possible to provide a more spacious sound field. it can.

In the sound field adjustment method according to the first embodiment of the present invention, the density of the columnar diffuser increases as the distance from the sound source and / or the sound receiving point increases, and the columnar diffusion is not necessarily required. There is no need to use the body, but this density difference is important.
Due to the difference in the density of the columnar diffusers, it is possible to diffuse and reflect acoustic energy that has no directivity in the mid- and low-frequency range, and make acoustic adjustments that give a more spacious sound field as described above. Can be done.

Moreover, in the sound field adjustment method according to the first embodiment of the present invention, an effect that extreme phase interference of the primary reflected sound hardly occurs by generating the diffuse sound in the section of the initial reflected sound 300 is obtained. It is done.
The arrangement of the acoustic diffuser 500 may be adjusted so that there is no diffused sound in the silent section between the direct sound 200 and the initial reflected sound 300, and the diffused sound exists only in the portion of the initial reflected sound 300. Since the phase interference is reduced, a good sound field can be obtained.

In the sound field adjustment method according to the first embodiment of the present invention, the acoustic diffuser 500 is mainly disposed on the speaker P side.
For this reason, it is possible to add the diffuse reflection sound 360 to the direct sound 200 near the sound source, compared to disposing a diffuser on the wall or ceiling. Thereby, the diffuse reflection sound can be added to the primary reflection sound from the floor.
That is, even when there is an acoustic diffuser on the wall or ceiling, the sound energy and the diffuse reflected sound 360 are directly incident on the wall or ceiling, so that the acoustic energy can be further diffused. Furthermore, the acoustic diffuser 500 according to the first embodiment of the present invention has a multilayer diffusion structure.
For this reason, the effect of directional diffusion and temporal diffusion can be included in the diffusely reflected sound, and a significant sound field spreading effect can be obtained.

<Second Embodiment>
Another arrangement configuration of the acoustic diffuser according to the second embodiment of the present invention will be described.
As for the acoustic adjustment system X according to the first embodiment of the present invention described above, the example in which the acoustic diffuser 500 is mainly disposed on the left and right sides of the speaker P has been described. However, the configuration is not limited thereto, and a configuration in which the acoustic diffuser 500 is provided in a speaker stand, for example, is also possible.
With reference to FIG. 9, the structure which provided the acoustic diffuser 500 in the speaker stand 60 in this way is demonstrated. The speaker stand 60 can be configured, for example, such that the acoustic diffuser 500 is disposed on the base portion 610 and the speaker P is placed thereon. The diffracted sound 355 from the speaker P reaches the listener L as the diffuse reflection sound 360 by the acoustic diffuser 500. In addition to the base unit 610, a configuration using a speaker platform is also possible. Further, a configuration without using the base portion 610 is also possible. Furthermore, a configuration in which the acoustic diffuser 500 is additionally arranged around the speaker P, such as up, down, left, and right, or at a remote location is also possible.
Even with such a configuration, the above-described acoustic adjustment system X can be used, and similar effects can be obtained.
Hereinafter, specific processing of the arrangement of the acoustic diffuser 500 at this time will be described in detail with reference to the flowchart of FIG. These processes are performed while the control unit 150 of the PC 10 controls each unit in accordance with a program stored in the storage unit 120.

(Step S201)
The control unit 150 performs a sound field measurement process that is the same process as step S101 in FIG. At this time, it is also possible to measure a low frequency that is a so-called “flooring” when the vibration of the speaker P is transmitted to the floor.
At this time, it is possible to consider the arrangement of sounding devices such as dynamic speakers and tweeters of the speaker P, the material of the floor, the material of the speaker base 60, the material of the base portion 610, the attenuation by the insulator, and the like.

(Step S202)
Next, the control unit 150 performs an arrival time calculation process, which is the same process as step S102.
In this arrival time calculation processing, in addition to the calculation related to the section from the arrival of the direct sound 200 to the arrival of the initial reflected sound 300 in FIG. 5, the level and arrival time of the floor sound are also calculated. It can be carried out.

(Step S203)
Next, the control unit 150 performs an arrangement condition calculation process that is the same process as step S103.
In this processing, the arrangement condition is such that when the diffracted sound 355 of FIG. 9 reaches the speaker base 60, the diffuse reflected sound 360 of FIG. 5 is between the direct sound 200 and the initial reflected sound 300. .
In the arrangement condition calculation process, specifically, the control unit 150 determines the number of acoustic diffusers 500 to be arranged on the speaker base 60 in the column, as in the arrangement of the acoustic diffusers according to the first embodiment described above. Interval, column-to-column spacing, and the like.
At this time, if the acoustic diffuser 500 is arranged in addition to the speaker base 60, the arrangement is also obtained.

(Step S204)
Next, the control unit 150 performs floor noise calculation processing.
Here, using the above-described calculation results of floor noise, an arrangement is calculated in which the frequency of the floor noise is canceled or a bass component remains as a diffuse reflection sound between the sound and the reverberation sound.
Specifically, by adjusting the diameter and arrangement of the thick columnar diffuser, the bass component of the diffuse reflected sound can be obtained within the time range until the bass component of the floor noise reaches the listener L. Perform placement. As a result, flutter caused by floor noise can be reduced, and the sound field can be enriched.

[Configuration of speaker stand 60]
Referring to the plan view of FIG. 11, the speaker stand 60 according to the second embodiment of the present invention uses the acoustic diffuser 500 according to the arrangement condition calculated in the arrangement condition calculation process described above. Constitute.
FIG. 11 is an AA cross section of FIG. 9 and shows an example in which the acoustic diffuser 500 is arranged on the speaker base 60 and the base portion 610.
The base portion 610 is made of wood, plywood, metal, plastic plate or the like having a high internal loss, and may include an insulator or the like so as not to directly touch the floor.
In addition, the acoustic diffuser 500 is fixed by removing a part of the base portion 610, or is fixed by a nail, a screw, a dowel, or the like.
The end where the acoustic diffuser 500 is in contact with the speaker P (FIG. 9) is processed, for example, flatly, and is bonded with anti-slip and vibration-preventing butyl rubber or elastomer. Further, the contact area with the speaker P can be reduced by processing the end into a convex shape. Thereby, it is possible to prevent the vibration of the speaker P from being directly transmitted to the floor.
Note that, as described above, a configuration in which a speaker mount is provided at a location where the acoustic diffuser and the speaker P are in contact is also possible. In this case, an insulator or the like can be provided on the speaker platform. Conversely, a configuration in which the end portion of the acoustic diffuser 500 is in contact with the floor using the base portion 60 as a speaker platform is also possible. Further, the base portion 610 may be provided with marble, zircon sand, or the like to increase weight, suppress vibration, and increase stability.
In addition, the acoustic diffuser 500 is not necessarily a cylinder or an elliptical column, and in order to generate diffuse reflection sound 360 vertically and horizontally, the center of the acoustic diffuser 500 swells like so-called “entasis” or a ball-like shape is connected. Such a diffuser may be used. Furthermore, a skewered configuration of spherical, elliptical, and uneven objects is also possible.
Further, the speaker P may be installed only in a part of the acoustic diffuser 500, and the acoustic diffuser 500 may surround the speaker P. Similarly, a configuration in which the acoustic diffuser 500 is attached above the speaker P is also possible.

By comprising as mentioned above, the stand which puts the speaker P and the acoustic diffuser 500 can be put together as the speaker stand 60, and an installation area can be reduced. On this basis, similarly to the first embodiment described above, diffuse reflection sound can be generated between the direct sound and the initial reflection sound, and the sound field can be adjusted well.
Also, by arranging the speaker base 60 on the acoustic diffuser 500, it is possible to perform acoustic adjustment with diffuse reflected sound even in a situation where it is difficult to provide the acoustic diffuser around the speaker P such as near the wall.
Furthermore, since a plurality of acoustic diffusers 500 are arranged, the stability is high. In addition, since the arrangement of the acoustic diffuser 500 is random, it is possible to suppress the natural vibration or the like derived from the housing of the speaker P from being transmitted to the floor. For this reason, the function which suppresses the bad influence to the sound field of an acoustic room as a speaker stand is acquired.
In addition, by calculating and suppressing the sound of the floor in the speaker base 60, the sound diffuser 500 is arranged to cause the sound of the floor that has caused the flutter echo and the like to deteriorate the sound field of the acoustic rooms. Can be used like part of sound. Thereby, it can be used for improving the sound field feeling of various acoustic rooms, and the sound field can be enriched. That is, even in a narrow acoustic room, sound waves such as low-frequency reverberation can be obtained, and the listener L can experience a wide sound field as in a large room such as a concert hall.

Note that the acoustic diffuser 500 according to the arrangement condition calculated in the arrangement condition calculation process described above is not limited to a speaker stand, but an audio amplifier (Amplifier) stand, an AV (Audio Visual) rack, a living table, a chair, and a floor. It can also be used for furniture including furniture and furniture such as lights and ceiling lighting. The furniture including the furniture and the like is also calculated and arranged so that the diffuse reflection sound is inserted in the section between the direct sound and the initial reflection sound in the acoustic rooms.
At this time, the sound field can be further enriched by using the acoustic diffuser around the speaker and the speaker stand together.
In addition, cords such as speaker cords, power cords, and optical fibers can be passed through or placed on the surface of the above-mentioned columnar acoustic diffuser to simplify cord connection and save space. It is also possible to do.

  It should be noted that the configuration and operation of the above-described embodiment are examples, and it is needless to say that the configuration and operation can be appropriately changed and executed without departing from the gist of the present invention.

10 PC
20 sound field measurement unit 30 input device 40 display unit 50 printer 60 speaker stand 110 input unit 120 storage unit 130 time calculation unit 140 arrangement calculation unit 150 control unit 160 output unit 200 direct sound 300 initial reflection sound 310 front wall reflection sound 320 ceiling Reflected sound 330 Floor reflected sound 340 Rear wall reflected sound 350 Side wall reflected sound 355 Diffracted sound 360 Diffused reflected sound 400 Reverberant sound 500 Acoustic diffuser 550 Acoustic diffuser group 610 Base part P Speaker L Listener X Sound field adjustment system

Claims (11)

An acoustic adjustment method for adjusting the sound field of acoustic rooms,
An acoustic adjustment method characterized by generating diffuse reflection sound in a section between a direct sound that reaches a sound receiving point from a sound source and an initial reflection sound. The acoustic adjustment method according to claim 1, wherein the diffuse reflected sound is also generated in the section of the initial reflected sound. The diffuse reflection sound is generated by arranging a diffuse reflector on the sound source and / or sound receiving point side,
The irregular reflector has a structure for multilayer irregular reflection with a gap,
3. The diffuse reflector is arranged so that its density increases as the distance from the sound source and / or sound reception increases, and the diffuse reflected sound is generated between the sections. 4. Acoustic adjustment method. The acoustic adjustment method according to claim 1, wherein the irregular reflectors are randomly arranged. 5. The acoustic adjustment method according to claim 1, wherein the irregular reflector is a columnar diffuser having an approximately circular column, an approximately rectangular column, or an approximately elliptical column, each having a different diameter. The acoustic adjustment method according to claim 5, wherein the columnar diffuser has a skewered shape. The acoustic adjustment method according to any one of claims 1 to 4, wherein the irregular reflector is one of a spherical shape, an elliptical spherical shape, and a skewered shape of an uneven object.   The sound adjustment program which performs the sound adjustment method of any one of Claims 1 thru | or 7 with a computer.   A sound field adjustment system comprising the computer that executes the sound adjustment program according to claim 8.   The speaker stand which calculated arrangement | positioning of the said irregular reflector by the acoustic adjustment method of any one of Claims 1 thru | or 7.   The furniture which calculated arrangement | positioning of the said irregular reflector by the acoustic adjustment method of any one of Claims 1 thru | or 7.

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