JP4255421B2 - Residential sound simulation system - Google Patents

Description

  The present invention relates to a sound simulation using a sound ray method and a system capable of outputting a result in consideration of transmission through a wall.

  Conventionally, simulation of sound transmission using a computer has been performed. In many cases, wave analysis using the finite element method or boundary element method has been the mainstream, but because wave analysis requires a large amount of calculation, it takes a long time and requires a lot of computer resources. There's a problem.

  Therefore, in recent years, a calculation method called a sound ray method is often used. This is to express sound transmission by quantizing the sound emitted from the sound source and expressing it as a sound ray, and calculating the sound pressure of the sound ray that is reflected and arrives. Furthermore, if only the sound rays emitted from the sound source are calculated, the density of the sound rays at the desired position is not stable. Has been proposed.

  The sound ray method is known to be an effective means for simulating the sound environment because the calculation is relatively simple and the amount of calculation is small compared to the wave analysis method. In particular, the sound ray method is suitable for analysis of a closed space such as a hall. For example, Japanese Patent Application Laid-Open No. 6-11386 can be used in combination with the mirror image method to obtain a simple and good simulation result. .

JP-A-6-11386

  However, the sound ray method, in principle, seeks transmission of sound by reflection, and ignores the wave nature of sound. For this reason, although it is suitable for the simulation of a closed space, when a boundary such as a wall or a partition exists in the space, the sound ray cannot cross the barrier.

  On the other hand, considering the case of simulating sound transmission in a house, unlike a hall or the like, a house has many barriers such as walls and partitions, and if the sound ray method is applied as it is, a satisfactory result cannot be obtained.

  There have been proposals for considering a barrier in the sound ray method. For example, the sound ray path is calculated assuming that there is no barrier, and then the reflected sound ray path is calculated in consideration of the barrier. Then, similarly to the attenuation of sound pressure due to reflection, it is conceivable to calculate the sound transmitted across the barrier by calculating the attenuation of sound pressure due to transmission. However, since sound is a wave, the ray vector should be lost when the barrier is crossed.

  It is also conceivable to set a temporary sound source on the surface opposite to the intersection of the barriers at the intersection (reflection point) between the barrier and the sound ray. However, although it is usually a simple calculation for one sound source, setting a temporary sound source for each intersection and computing the omnidirectional sound ray in the same way as a normal sound source requires a large amount of calculation. The advantage of the ray method, which increases dramatically and is simple to calculate, is significantly impaired.

  Accordingly, an object of the present invention is to provide a simulation system that can easily calculate a sound environment in a house with many barriers using a sound ray method and obtain a good result closer to an actual measurement value.

In order to solve the above-described problems, a typical configuration of sound simulation of a house according to the present invention includes an input unit that inputs floor plan information and sound source information of a building, and a route calculation unit that calculates a route due to reflection of sound rays. A sound source setting means for setting a sound source at a position opposite to the point of intersection of the barrier with respect to the intersection of the sound ray and the barrier, and a sound for calculating a sound pressure level along the path of the sound ray and a pressure level calculation means, the temporary sound source setting unit, for one intersection to set the plurality of temporary sound sources, for each of the provisional tone set one to a plurality of sound rays, and a plurality of temporary sound source, It arrange | positions in the circle centering on the position which opposes the said intersection .

  According to the present invention, a plurality of temporary sound sources are set on the side opposite to the intersection of the barriers, and one or more sound rays are set for each temporary sound source. It is possible to obtain a good simulation result closer to the actual measurement value by simply calculating using.

  A residential sound simulation system according to the present invention will be described. FIG. 1 is a schematic configuration diagram of a sound simulation system according to the present embodiment, FIG. 2 is a flowchart illustrating characteristic operations of the present embodiment, FIG. 3 is a diagram illustrating an example of setting a temporary sound source and sound rays, and FIG. Is a diagram showing an example of an absorptance database, and FIG. 5 is a diagram showing an example of frequency characteristics of a sound source.

  As shown in FIG. 1, this system includes a system main body 1, input means 2, and output means 3. The input unit 2 is a unit for inputting information necessary for calculation, and includes an input device such as a keyboard and a mouse, a storage medium, a network, and the like. The output means 3 outputs a calculation result, and includes a monitor for displaying a screen, a printer for printing, a recording medium for saving as data, and the like.

  The storage area 11 of the system body 1 stores floor plan information and sound source information input from the input means 2. The floor plan information includes spatial coordinate information such as room dimensions and wall thickness, and barrier information such as wall material and type. Further, as shown in FIG. 4, the system main body 1 includes an absorptance database 12 in which the absorptivity (sound absorption rate) is stored for the wall material and type. The sound source information includes the spatial coordinates (position) of the sound source and the characteristics of the sound source (frequency characteristics, directivity, intensity). The absorption rate database 12 does not necessarily have to be incorporated in the main body, and can be supplied by a recording medium such as a network type or a CDROM as necessary.

  Further, the system main body 1 includes a path calculation means 13 for calculating a sound ray path, a temporary sound source setting means 14, and a sound pressure level calculation means 15. The route calculation means 13 calculates the sound ray route and calculates the intersection of the barrier and the sound ray. The temporary sound source setting means 14 sets a temporary sound source for each intersection, and the detailed operation will be described later. The sound pressure level calculation means 15 calculates the sound pressure at each intersection (including the end point of the sound ray) along the sound ray path. Each element of the system main body 1 is connected to the CPU 10 to perform predetermined processing.

  In practice, the storage area 11 is storage means such as a RAM or a hard disk, and the absorption rate database 12 is data stored in the storage means. The route calculation means 13, the temporary sound source setting means 14, and the sound pressure level calculation means 15 are modules realized by a program, and are read by the CPU 10 and perform predetermined operations as hardware.

  Since the calculation method of the sound ray method is already well known, a detailed description is omitted here. Briefly, when only the sound ray method is used, first, a large number of sound rays are set at predetermined intervals from the sound source, and the intersections of the sound ray vectors and the walls are determined. Then, the direction of the sound ray to be reflected is determined according to the angle of the vector and the wall, and the next intersection is determined. If the reflection reaches a predetermined number of times, no further reflection is made (the end of the sound ray is the intersection with the wall). When the intersections and paths are determined for all sound rays, the sound pressure level is calculated along each path while considering attenuation due to distance and attenuation due to reflection. The calculation of the sound pressure level may be performed before the calculation of all the paths is completed (for example, every time one sound ray path is determined).

  However, since the sound ray density varies only with the sound ray method, it is often used together with the virtual image method. When the virtual image method is used, a sound receiving point is set, a virtual image of the sound source is created at a position symmetrical to the barrier, and the point where the sound ray connecting the virtual image and the sound receiving point intersects the barrier is defined as the intersection (reflection point). Ask. When considering two-time reflection and three-time reflection, first, a virtual image is created at a position symmetrical to the barrier that can be reflected, and then a virtual image of a virtual image is created for the barrier that can be reflected. In response, a superimposed virtual image is created. The calculation of the sound pressure level is the same as described above. By calculating in this way, the sound ray density is stabilized, so that the calculation accuracy can be improved and the calculation amount can be greatly reduced.

  Next, characteristic processing of the present invention will be described with reference to FIGS. 2 and 3. As shown in the figure, first, using the path calculation means 13, the intersection of the (primary) sound ray emitted from the sound source and the barrier is obtained by the conventional sound ray method or virtual image method, and an intersection list is created. (S1). Here, if the sound receiving point (position to be measured) is determined and the sound source and the sound receiving point are spatially continuous, it is effective to use the virtual image method. However, when there are many barriers such as a house and the space (room) is closed, no sound ray is generated, so that no intersection is generated in step S1. Therefore, in this embodiment, it is desirable to use the conventional sound ray method for setting sound rays from a sound source.

  Next, the temporary sound source setting means 14 sets a plurality of temporary sound sources on the opposite side of the intersection of the barrier for one of the intersections in the intersection list, and sets one or more sound lines for each temporary sound source. (S2). Here, the temporary sound source is not a sound source that actually exists, but is assumed that the barrier vibrates due to sound energy as a wave and becomes a sound source. For example, as shown in FIG. 3A, the temporary sound source and the sound ray thereof have a predetermined size at a position opposite to the intersection point 22 of the barrier 20 with respect to the intersection point 22 of the barrier 20 and the sound ray 21. A circle 23 is set, one temporary sound source 24a is set at the center of the circle 23, and four temporary sound sources 24b are set on the circumference. Sound lines 25a and 25b parallel to the central axis of the circle 23 are set for the temporary sound sources 24a and 24b.

  Then, the CPU 10 specifies one sound ray from the sound rays 25 newly generated in step S2 (S3), and again calculates the intersection point by the route calculation means 13 (S4). At this time, the number of intersections (number of reflections) is determined based on whether the number of reflections and transmissions from the original sound source has reached a predetermined number (S5). If the sum of the number of reflections and the number of transmissions is less than the predetermined number in step S5, the newly calculated intersection is added to the intersection list (S6), and the next intersection is obtained (S4). For example, when the predetermined number of times is 3, and the intersection obtained in S1 is the first reflection, the temporary sound source and the sound ray set for the intersection have the number of transmissions of 1, and the sound ray is 2 Calculate up to the reflection. When the intersection obtained in S1 is the second reflection, the temporary sound source and the sound ray set for the intersection have the number of reflections of 1 and the number of transmissions of 1, so the sound ray is calculated until the first reflection. To do. In this way, calculation is performed for all sound lines newly generated for one intersection (S7).

  The processes in steps S2 to S7 are performed for all intersections stored in the intersection list (S8). Here, as described above, the intersection is added to the intersection list in step S6. However, the increase in the number of intersections converges early because of the limitation of the number of reflections in step S5, and the calculation ends.

  The temporary sound source 24 and the sound lines 25 set for each temporary sound source are limited in the present invention by setting a plurality of temporary sound sources for one intersection and setting one or a plurality of sound lines for each temporary sound source. That is, other configurations can be appropriately set. Particularly characteristically, the sound ray 25 set from the temporary sound source 24 is in the point of not inheriting the direction of the colliding sound ray 21 (which is related to the sound pressure).

  For example, the arrangement pattern of the temporary sound source 24 may be four points arranged equally on the center point and the circumference as shown in FIG. 3A, or may be three points on the circumference as shown in FIG. Good. A temporary sound source may be arranged at an intermediate point in the circle that does not reach the outer periphery of the circle. Although it is expressed that it is arranged on the circumference, it goes without saying that if it is 4 points, it is synonymous with being arranged at the vertex of a rectangle, if it is 3 points, it is arranged at the vertex of a triangle. Absent. Further, as in the present embodiment, the temporary sound source is preferably arranged symmetrically with respect to the central axis of the circle 23, but may be non-uniform depending on the situation (when considering the vicinity of the end of the barrier or a column, etc.) ).

  Further, as shown in FIG. 3A, the strength of the temporary sound source is preferably increased toward the center of the circle 23, but it is not always necessary to provide a difference.

  The vector (direction) of the sound ray 25 set for each temporary sound source 24 may be parallel to the central axis of the circle 23 as shown in FIG. 3A, but as shown in FIG. It may be set so as to diffuse radially around the 23 central axis. Further, as in the example shown in FIG. 3C, two or more sound rays 25a may be set in the temporary sound source 24a, and the vectors may be distributed by giving an angle to each. However, if a plurality of sound rays 25 are set, the calculation accuracy is improved, but the amount of calculation increases greatly. Therefore, it is preferable to set as few as possible.

  The number of temporary sound sources 24, the arrangement pattern, the direction of the sound ray vector, the size of the circle 23, and the strength of each temporary sound source 24 are dynamically changed parameters. These are appropriately determined according to the type and area of the barrier, the sound pressure level at the intersection 22, and the absorption characteristics of the barrier obtained by referring to the absorption rate database 12.

  As shown in FIG. 4, the absorption rate database 12 stores a sound absorption rate corresponding to a frequency band for each type of barrier. For example, a circle for a gypsum board is set as a reference circle. The absorptivity for 125 Hz of the gypsum board is 0.35. On the other hand, the decorative board 2 has a lower absorptance at 125 Hz (low frequency) than other frequencies, that is, it easily passes low frequencies. The absorption rate at 125 Hz, which is the most easily transmitted frequency, is 0.7, which is twice the 125 Hz absorption rate of the reference gypsum board. Therefore, the size of the circle for the decorative board 2 is 0. 0 of the reference circle. Set 5 times.

  It is also effective to consider the sound source having a specific frequency characteristic and the frequency absorption characteristic of the barrier against these. FIG. 5 shows an example of frequency characteristics stored as sound source information. The FFT (Fast Fourier Transform) shown in the figure is preferably performed by the Blackmann-Harris method in the range of 128 points (divided) to 512, preferably 256. Usually, the FFT related to sound samples about 11 KHz to 48 KHz, but this time, it is preferable that the FFT is as rough as described above. The reason is that by simplifying the sound, the noteworthy frequency becomes clear.

  As an example of considering the frequency characteristics of the sound source, in the case of a piano having a wide frequency band, the number of temporary sound sources is set to be large so that it can correspond to various frequencies. In addition, in the case of sound sources that mainly contain low frequencies, such as home theater woofers and footsteps, the size of the circle is set larger. In the case of a sound source mainly including a relatively high frequency such as a metal sound or a child's voice, a setting is made to reduce the circle or the number of temporary sound sources. On the other hand, as an example of considering the frequency absorption characteristics of the wall, in the case of a wall using soundproof material, the provisional sound source setting method is set to a high frequency, although it contains many low frequency components such as piano sounds and woofers .

  In particular, by changing the number and arrangement of temporary sound sources, a surface sound source can be expressed in a pseudo manner. Thereby, a favorable simulation result can be obtained.

  The present invention can be used for sound simulation in a building with many barriers such as a house.

1 is a schematic configuration diagram of a sound simulation system according to an embodiment. It is a flowchart explaining the characteristic operation | movement of a present Example. It is a figure which shows the example which sets a temporary sound source and a sound ray. It is a figure which shows the example of an absorption factor database. It is a figure which shows the example of the frequency characteristic of a sound source.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... System main body 2 ... Input means 3 ... Output means
10 ... CPU
11 ... Storage area
12… Absorption rate database
13: Route calculation means
14 Temporary sound source setting means
15… Sound pressure level calculation means
20… Barrier
21 ... Sound ray
22 ... Intersection
23 ... yen
24 Temporary sound source
25 ... Sound ray

Claims (6)

An input means for inputting floor plan information and sound source information of the building;
A route calculating means for calculating a route by reflection of the sound ray;
Temporary sound source setting means for setting a temporary sound source at a position opposite to the intersection of the barrier with respect to the intersection of the sound ray and the barrier,
A sound pressure level calculating means for calculating a sound pressure level along the path of the sound ray,
The temporary sound source setting unit, for one intersection to set the plurality of temporary sound sources, for each of the provisional tone set one to a plurality of sound rays, and a plurality of temporary sound source, around the position opposed to the intersection A sound simulation system for a house characterized by being placed in a circle . The temporary sound source setting unit, sound simulation system of claim 1, wherein housing, characterized in that said plurality of temporary sound source are arranged axially symmetrically with respect to the center axis of the circle. The temporary sound source setting unit, sound simulation system of claim 1, wherein housing the plurality of temporary sound sources, and sets the strong sound pressure toward the center within the circle. 2. The sound of a house according to claim 1, wherein the temporary sound source setting means sets the sound ray vectors to be set for the plurality of temporary sound sources so as to diffuse radially around the center axis of the circle. Simulation system. The temporary sound source setting unit, a sound simulation of claim 1, wherein housing, characterized in that the size and distribution of the plurality of temporary sound source of the circle is changed according to the characteristics of the barrier included in the floor plan information system. 2. The sound of a house according to claim 1, wherein the temporary sound source setting means changes the size of the circle and the distribution of the plurality of temporary sound sources according to the frequency characteristics of the sound source included in the sound source information. Simulation system.

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