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[PROBLEMS] To provide a sound insulation system that eliminates noise generated when using a
portable toilet and can be used without hesitation. The sounds are all sine waves. The generated
sound is sensed by a sensor microphone placed close to it, and this is input to the operational
amplifier circuit. This output waveform is an inverse sine wave to the input waveform. Use the
fact that there is a six-digit speed difference between the sound wave and the current transfer
speed. Within a slightly shifted time after the sound generation begins to spread in space, the
reverse sine wave can be output from the speaker ahead of the other side of the sound
generation source to strike the sound generation. It is possible to cancel the generated sound by
the negative interference with the same waveform. In addition, this speaker has a function of
canceling the sound output from the back side. The combination of this system and a sound
absorbing sound insulation screen with the same degree of softness as a normal curtain can
prevent external leakage of sound. [Selected figure] Figure 1
Sound insulation system that leaks the sound to the outside even if it is an open space when
using the portable toilet indoors.
It is about the silencing system of the small space which can not be sealed easily in a room etc.
In the past, as a countermeasure, muffling in the toilet creates an imitation sound that resembles
the flow of water, and this method is used to cover the sound generated when using the toilet.
However, this only makes the generated sound indistinguishable from the outside, and although
the purpose is achieved, it can not be used in the middle of the night. In the muffling using the
phase opposite to the generated sound, there are embodiments in which the sound in the air duct
is erased or the exhaust gas noise from the engine is erased with a silencer. This is to detect and
analyze each frequency of the noise component with a microphone. An anti-phase sound wave
corresponding to this frequency is put on the speaker in the same forward traveling direction
and output. The remaining sound is picked up as a feedback signal by another sensor
microphone located downstream, and the frequency is finely adjusted and transmitted
accordingly to cause negative interference. In these cases, the sound passing through the closed
container such as a duct is sent back one after another by transmitting the one with the reverse
wavelength, and the response is intended in the open space as in this case. Not applicable to
Further, with regard to the sound absorbing material, there are some which perform processing
of many peaks and valleys on the surface based on a sponge-like sound absorbing material to
attenuate the energy of sound. A very thick material is required to achieve the effect required by
the present invention. Although it is optimal for a large art stage hall or a large sound insulation
room, it can not be used as a wall to create a smaller space in a narrow room like this case.
Conventionally, there is a theory of "mass law" in which only the mass of the sound insulating
material is concerned in order to obtain a sufficient sound insulation effect. It is a theory that
sound can be isolated only by using a thick concrete wall or a thick metal plate. However,
recently, a method has been put to practical use that gives viscous resistance to air through
which sound propagates, and thereby attenuates the energy of the sound by internal loss. There
are thin ones with a thickness of 6 to 10 mm, and a plate made by pressing and sintering
aluminum material fiber or aluminum material fiber with high sound absorption performance
and aluminum chip is put to practical use as a wall type sound absorbing material .
Portable toilets used indoors are often used late at night when others are sleeping. In this case, it
is fine if the place of use is a private room and it is a sealed state where complete sound
insulation is possible, but if there is a roommate or there is a room next to one another, other
people will make a annoying noise. It will be ridiculous. Similarly, the sound of using the portable
toilet on the bed side of the hospital has to pay attention to others from shame. From such an
environment of use, the functions required for this system are: 1) It is not a wall or plate fixed for
use in a narrow room. {Circle around (2)} Since the generated sound is in a low frequency region,
it can be handled. である。 The above-mentioned wall-type sound absorbing material put to
practical use exhibits effective performance in the high frequency region per 1000 Hz. However,
satisfactory performance can not be obtained in the low frequency region of 400 to 800 Hz
required by the present invention. The sound insulation system according to the present
invention is intended to eliminate noise generated when using the toilet and to be used without
hesitation to the surroundings without hesitation.
About the system for eliminating noise generated in open space according to [claim 1]. By
utilizing the difference in the transfer speed between the sound wave and the current, the phase
is reversed by the amplifier from the opposite direction to the sound progress with a slight delay
time after the sound from the source starts to propagate into space as a spherical wave. The
sound is output from the speaker and hit it. By causing negative interference between the
forward-rotated reverse sine wave and the generated sound, the generated sound can be
eliminated. It was possible to prevent the noise generated during use, such as portable toilets,
from leaking out even if not sealed. About the speaker back surface noise cancellation apparatus
of [Claim 2]. Normal speaker sounds come out from the front side and some from the back side.
Especially in the case of a flat speaker, the directivity of the sound is excellent, but the output has
the same characteristics on both sides. By enabling the back side muffling, only the reverse sine
wave coming out of the front side can be used for negative interference with the generated
sound. It consists of the following functions. 1) Back side speaker sound guide part. {Circle over
(2)} flat plane speaker. The reverse sine wave sound from the back surface speaker causes
negative interference with the sound generated from the small flat speaker at the sound guiding
portion and cancels it. This makes it possible to have a function that does not cause the sound
distortion phenomenon. About the sound absorption type sound insulation screen of [claim 3].
Because it has the function to cope with low frequency to high frequency area and also has
softness, the sound absorbing type sound insulation screen that can be used like the ordinary
curtain is composed of the following functions. {Circle over (1)} A layer consisting of metal
microfibers. {Circle over (3)} Forced vibration theory is used, and since it is connected by the
front pole thin plate that receives and vibrates the energy of the sound wave and the soul
column, the noise is silenced by the negative interference with the back pole thin plate in
antiphase. A layer consisting of a group of cells consisting of these two extremely thin plates, a
soul pillar connecting them, and a knitting net. This makes it possible to use a sound-absorbing
sound barrier that can be operated with the simplicity of drawing a blindfold curtain from the
surroundings when in use.
Effect of the invention
The condition required in this case is to mute all the generated and propagated sound from the
first part. It is an absolute requirement to mute the first sound generated. Therefore, analyze the
sound waves as in the conventional system, create an inverse sine wave of the sound generated
first, and naturally follow up with the first sound wave that is the same speed, even if you chase
after for negative interference It is not possible to erase it. It is the sound wave after that which
can be erased and can not meet the purpose of this case. However, it is possible to eliminate the
sound wave from the beginning by utilizing the overwhelming difference between the speed of
sound and the current transfer speed as in the present invention. As the generated sound starts
to propagate in the air, the sound taken in by the closely-located sensor microphone is input to
the amplifier circuit to create a reverse sine wave of this. The generated sound is struck from the
speakers installed in advance in the propagation direction of the generated sound, and the
impact waveform is generated by the reverse waveform output from the amplifier circuit. As a
result, negative interference occurs between the first generated waveform and its reverse
waveform, and the generated sound is eliminated. Subsequent sound waves are similarly
interfered and canceled. Specifically, we will describe the velocity of propagation and the
distance between the two. The speed of sound is 340 m / s in air at 15 ° C. The current velocity
V flowing in the copper wire is expressed by the following equation according to the relationship
between the electric field and the electric flux. <img class = "EMIRef" id = "202458937-00003"
/> When each numerical value is substituted, it becomes V = 299, 792, 458 m / s. That is, it
could be confirmed that the transmission speed of the current flowing through the copper wire
cable was the same as the speed of light C. Next, the generated sound is sensed by a nearby
sensor microphone, a reverse waveform is made, and the time required for this current to reach a
speaker 3 m ahead is calculated. 1) Sensor microphone sensing input 80 80 μs between op amp
output terminals 2) Op amp output terminal の 間 between antiphase speakers (distance 3 m) 3
m / 299, 792, 458 m / s = 0.011 μs total 80.011 μs Meanwhile, within this time And the
distance traveled by the generated sound is 340 m / s × 8 0.011 μs = 27.2 mm. That is, the fact
that the inverse sine wave is transmitted from the speaker installed on the opposite side with the
progress of the sound comes after the generated sound propagates about 27 mm in space as a
spherical waveform. Even if the difference is 27 mm, it can not catch up even if it sends a reverse
sine wave in the same direction as a follow-up, and the first generation sound can not be deleted.
Moreover, although it is the method of striking a reverse sine wave with respect to the
generation ¦ occurrence ¦ production sound from a reverse direction, the objective can be
achieved if it is closed space, such as a duct. However, this method can not be applied to the
sound propagating in space as a spherical wave. As a solution means, it was possible by
transmitting a reverse sine wave downward from the speaker installed on the diagonal upper
side. Thus, the generated sound propagating as a spherical wave can be captured.
As shown in the left side view of FIG. 1, the position of the speaker is set slightly forward of the
user. This causes the height position of the ear to coincide with the negative interference area.
The noise does not go out and at the same time the user can not hear it, so there is no excessive
will to others, and you can calm down and use the toilet. As in the 1-1 and 1-2 plan views, the
sound absorbing type sound insulation film of [5] of [claim 3] is disposed on both the rear sides
and the floor. As a result, the generated sound reaching the rear is substantially converted into
mechanical friction and vibration energy and does not leak to the outside. As shown in a plan
view 1-3 of FIG. 1, when three speakers are used because no sound absorbing sound insulation
screen is provided around the area, an area where positive interference occurs due to inverse
sine waves occurs. Contrary to the purpose, the amplified sound is generated. In order to avoid
this, as shown in 1-3 plan view of FIG. 1, the sound absorbing type sound insulation curtain of
[claim 3] which absorbs the sonic energy is installed in the state of hanging from the upper part
Do. This makes it possible to eliminate the generated sound without creating a closed state. 3 3
▼ Use flat speakers for the speakers. Ordinary cone speakers are not suitable for this system
because they take up a lot of space, acoustic energy diffuses from a certain point (sweet pot), and
acoustic energy becomes non-linear. On the other hand, since a flat speaker generates a driving
force on the entire surface of a flat diaphragm, it radiates a plane wave as a plane sound source
and has a flat phase and sharp directivity. For this reason, with respect to the spherical wave of
the generated sound, it is possible to radiate an inverse sine wave having a flat phase and a sharp
directivity, so that negative interference which can satisfy the condition can be performed.
Moreover, although it is the same as a cone speaker, especially a flat speaker has the
characteristic that the sound of the same output as the front will be emitted also on the back side.
In order to solve this problem, it is sufficient to provide a sound shielding plate in a state in
which the back side is sealed, but since there is no escape place for sound energy, a lingering
sound phenomenon occurs. [Claim 2] is about the speaker back side muffling system as a
solution to this. As shown in FIG. 2, the structure (3) is provided with a sound conducting portion
(8) for sound wave escape on the back of the speaker. The sound absorbing and insulating screen
of [claim 3] is attached to the inside, so that the sound can not escape. The same sine wave
speaker is installed at the right center of the looped {8} sound conductor. (3) At the time of
speaker output, (7) The sound wave output from the back of the speaker travels in this without
being scooped by the effect of the sound guides on both sides.
On the other hand, (9) the same sine wave speaker uses a flat speaker, (1) the sound generated
from the sensor microphone is output as it is from the front and back. As a result, (8) negative
interference occurs in the sound conductor and the energy of the sound disappears. This solves
the sound distortion phenomenon.
The sound absorbing type sound insulation screen of [claim 3] will be described in FIG. The
material of the (20) aluminum fiber layer used on the front side and the back side has a
characteristic that it has a sound absorbing function more than 10 times that of glass wool and is
lightweight. The fibers have an average diameter of 90 to 130 μm, a length of 10 to 20 mm, and
a surface density of 1000 g / m <2>. A non-hardenable binder is used to strengthen the cohesion
of the fibers in order to maintain the entanglement of the aluminum fibers even when external
forces such as bending and pulling are applied. As the binder, a tack / adhesive having a strength
of an acrylic ester of 1.55 kg / 25 mm in the 180 ° peel test is used. As a result, it became
possible to obtain a ▲ 20 ▼ aluminum fiber layer which satisfies the two conditions of having
no fraying while having flexibility. This aluminum fiber layer exhibits a high sound absorption
coefficient around 700 Hz in the middle frequency band to 1500 Hz in the high frequency band.
There are individual differences in the noise generated when using the toilet, and there are
places that are difficult to identify, but it is assumed to be 300 to 800 Hz as the average value by
actual measurement. This low frequency region is a region where the use of various sound
absorbing materials can not produce an effect. Even if it respond ¦ corresponds with the said
aluminum fiber considered to be the highest sound absorption performance, and its processed
goods, a result is inadequate. The noise reduction function based on the following forced
vibration theory corresponds to this. First, the cell space of {circle over (17)} which is sandwiched
between {11} front-side thin plate and {12} back-side thin plate and surrounded by {19} knitting
net in height and width height a × b × c. Each extra thin plate is etched to roughen the surface
to prevent sound reflection. The circumference of the inside of the {17} cell space becomes a
four-sided sidewall by softly adhering the {19} aluminum knitted net with the above-mentioned
binder. It is isolated from the adjacent cell space and has an independent structure. Due to this
structure, the vibration of the sound applied to the sound absorbing type sound insulation film is
captured as an external force causing the forced vibration. According to this consideration, it is
the present invention that the forced vibration theory is applied to enable noise cancellation.
There is a violin as a concrete example using forced oscillation theory from the rule of thumb.
The structure of the violin is such that the lateral vibration of the string caused by the slide of the
bow is converted to the longitudinal vibration by the piece supporting it from below. The
vibration is transmitted to the surface plate naturally because the piece is on the surface plate.
Next, the vibration of the front plate vibrates the back plate via the soul pillar (tonchul) set
between the back plate and the back plate. As a result, the vibration system of the front plate and
the vibration system of the back plate are connected by the soul column, and sound is
transmitted to each other.
Because the guitar does not have this soul, the body has only a simple resonance function. A
characteristic of the forced vibration theory is that a phase shift occurs due to the frequency
ratio between the vibration (ω) of the top plate vibrating upon receiving an external force and
the natural frequency (ω0) of the back plate. When ω = ω0 from the same phase when ω <ω0,
they mutually resonate (= resonance) to maximize the amplitude, and the phase is shifted by π /
2. In addition, when ω> ω0, the amplitude due to resonance gradually decreases, but the phase
deviates by approximately π (180 °), and the vibration of the back plate is in the opposite
phase. As a result, the back plate causes positive or negative interference with the front plate. In
an actual violin, the surface plate is made of spool material, the back plate is made of a material
different from that of maple material, and the thickness is adjusted to create a subtle difference
in frequency to create the depth of sound. The equation of motion of forced vibration is
expressed as follows.
As a matter of course, the vibration of electrons in an electric field, the vibration of mechanical
parts due to stress, the vibration of a building due to earthquake, and so on are respectively
expressed by the same forced vibration equations although different display symbols are used.
The equation of motion is obtained by adding an external force to the equation of damping
vibration. If the external force is a simple vibration of frequency ω, it will be <img class =
"EMIRef" id = "202458937-00004" /> If this is rewritten <img class = "EMIRef" id =
"202458937-000005" /> However, Γ γ γ / M F ≡ f / m <img class = "EMIRef" id =
"202458937-000006" /> ω0 = single vibration frequency without resistance or external force ω
= frequency of external force γ = damping constant δ = initial state The phase of m = mass = =
spring constant The following equation (3) can be obtained as a special solution by solving this
differential equation. This equation is a simple vibration. <img class = "EMIRef" id = "202458937000007" /> The following equation (4) is obtained from this equation. δ represents the phase
shift with the external force. tan δ = ωΓ / ω <2> -ω0 <2>-(4) <img class = "EMIRef" id =
"202458937-00008" /> As a solution of forced vibration, the side receiving external force is the
same as external force A single vibration having a frequency and a phase shift of δ is obtained.
The amplitude is expressed by equation (5). The fact that the phase is shifted with respect to the
external force means that it can not follow the external force exactly and follows the same cycle
delayed by δ. From the above, the amplitude A and the phase delay δ with respect to the
external force are determined by the relationship between the natural frequency ω 0 of the
oscillator, the damping constant γ and the frequency ω of the external force. FIG. 4 shows the
relationship between A, δ and ω / ω 0, and FIG. 4-1 is called a resonance curve or displacement
response magnification. According to the above equation (5), A = Fm / F at ω = 0, and A = Fm /
γω0 at ω = ω0. When ω = ω0 If the value of γω0 is small, then A becomes extremely large.
Here, γc is a γ value at critical damping {(γ / 2 m) <2> = ω0 <2>}, and corresponds to whether
or not a vibration phenomenon is exhibited due to the large resistance. Next, with respect to the
phase shown in FIG. 4-2, as shown in equation (4), when the condition is small, the delay angle δ
takes a small positive value at ω <ω0, and δ = π / at ω = ω0. In the condition of 2, ω> ω0, all
δ = π (180 °), that is, opposite phase. As described above for the violin, as long as the
relationship between the external force (ω) and the vibration value of the side (ω0) receiving the
forced vibration by this maintains the condition of ω> ω0, the mutual waveforms are negative
due to the reverse waveform. Interference occurs and mutual vibration disappears. That is, the
sound goes out.
In the sound absorption type sound insulation screen, as in the case of the vibration of the string
in the example of the violin vibrates the front plate, the sound of the generation source vibrates
the front electrode thin plate as the sound pressure by the air vibration ((11) Frequency = ω).
This vibration is π (180 °) from the original phase by forcedly vibrating the back plate which is
said with a violin via ▲ 15 魂 pillar, ie ▲ 12 裏 back electrode thin plate (natural frequency =
ω0) An out-of-phase wave is generated that is only offset, causing negative interference. In
principle, the first half-wavelength sound can not be erased. However, in the case of a sound of
400 Hz as an example, this half wavelength is 1/400 × 2, ie, 1/800, and there is no practical
problem as the sound insulation function. Relationship between vibration value and external
force to cause negative interference constantly To keep ω> ω0, determine the lowest frequency
of the target sound at the initial stage, and set the value below that value to ▲ 12 ▼ back
electrode thin plate It becomes possible if the natural frequency of is set. Assuming that the
lowest frequency of the noise to be muted is 400 Hz, the margin of the value of the natural
frequency ω 0 of the back plate may be set to about 360 Hz. Cause interference. Therefore, in
the case of a two-layer structure as shown in the right side cross sectional view of FIG. 3, it is
possible to target and erase the frequency corresponding to each layer in the zone. As an
example, if the first layer starts the corresponding frequency from 400 Hz, it is expressed as 1
<.omega ./. Omega.0.ltoreq.1.7 with a role up to about 1,7 times of this. Here, since ω0 = 360 Hz
as described above, ω ≦ 1.7 × 360 = 612 Hz, that is, 360 Hz to 612 Hz in the first layer can be
said to be the corresponding range. Similarly, in the second layer, ▲ 14 ▼ Assuming that the
natural frequency ω0 ′ of the back electrode thin plate is 612 Hz, 1 <ω ′ / ω0 ′ ≦ 1.7, and
hence the range of the electrode thin plate is ω ′ ≦≦ 13. It will be 1.7 × 612 = 1040 Hz.
Therefore, in the case of this example, an external force of 361 to 1040 Hz can be coped with by
setting the natural frequency to ω0 = 360 Hz and the double layer ω0 ′ = 612 Hz. As a result,
a sound absorbing sound insulation screen that can satisfy the requirements of the portable toilet
sound insulation system has become possible.
FIG. 1 shows an embodiment of [claim 1]. (5) The sound generated when the portable toilet is
used is (1) sensed by the sensor microphone and (2) taken into the amplifier control device. The
output is two kinds of sound waves in the same sine wave as that of the generated sound and the
inverse sine wave. These are connected to the speaker via the cable via the cable. The inverse
sine wave corresponds to the negative interference with the generated sound, and the same sine
wave is for the speaker back sound removal. This speaker is installed downward by an angle θ,
and can be used as a spherical wave so that it can almost catch an inverse sine wave as it
propagates. This reverse sine wave is output in the form of striking the generated sound from the
(3) speaker and causes negative interference with the generated sound around the height of the
user's ear. This erases the sound and does not enter the portable toilet user's ear. The 1-1 and 12 plan views of FIG. 1 are embodiments in the case where one speaker is used. These are
examples of using portable toilets on the bedside of a hospital and in single rooms. When one
speaker is used in this manner, the generated sound spreads in a spherical wave, which results in
a range in which negative interference can not be caused. In order to cope with this, (5) sound
absorption type sound insulation curtains are arranged as shown in the plan views 1-1 and 1-2,
and (3) the generated sound which can not be dealt with the inverse sine wave from the speaker
is eliminated. (5) There is also a fixed installation method for sound absorption type sound
insulation curtains, but make use of the same flexibility as cloth, and when not in use, roll up and
store them together with the winding mechanism (plan view 1-1), or It can be suspended by a
curtain rail and bundled at one of the left and right ends (plan view 1-2). Also, the sound
generated downward from the portable toilet body is muted by the muffling mat on the floor. The
plan view 1-3 is an example in which no sound shielding screen is arranged in the periphery in
order to avoid a feeling of blockage when enclosed. By suspending the three equally spaced
sound insulation curtains from above, sound amplification interference occurring at the
boundary of the three speakers is avoided. In addition, the flat speaker is used for (3) speaker.
The speaker has a spread angle of about 15 degrees at the end. As a result, it has become
possible to transmit a directional inverse sine wave in which the progress of the sound is less
likely to cause a phase shift at the center and at the end compared to the cone speaker.
FIG. 2 shows an embodiment of [claim 2]. Flat speakers have distinctive characteristics of
directivity, while the back side has the same output as the front side. The back sound cancellation
means, a serious drawback to the system, is shown in FIG. (7) From the back of the speaker, the
same one as the reverse sine wave used for noise cancellation is output. This sound wave splits in
two directions and travels in the sound guiding section {circle over (8)}. Along the way, the sound
waves output from both the front and back of the same sine wave speaker (9) which is a flat
speaker are negatively interfered with each other and the energy of the sound disappears. (8)
Sound conductor inside (10) A sound insulation material is installed, and no sound leaks. This
mutes the sound coming from the back of the speaker.
An embodiment of [claim 3] will be described with reference to FIG. The sound absorbing sound
insulation screen has the following configuration from the front side. The materials described are
those of the specific embodiment. 1) ▲ 20 ▼ Aluminum fiber layer: With the non-hardening
binder, the initial tensile and compressive strength can be maintained without being entangled
with the fibers. Physical properties of the binder are as described in line 6 of the abovementioned [0007]. 2) ▲ 20 役 目 Spacer: serves to avoid contact between the 20 20 と
aluminum fiber layer and ▲ 11 薄板 thin plate on the front side and ▲ 12 裏 back electrode thin
plate and ア ル ミ 20 ア ル ミ aluminum fiber layer on the back side . As a result, it is possible to
reduce the vibration resistance of the (11) front electrode thin plate and the (12) back electrode
thin plate. It enables antiphase by forced vibration close to the theoretical value. The material is
aluminum. 3) {circle over (11)} Front thin plate: vibrates under the sound pressure of the
generated sound. {Circle over (12)} For the back electrode thin plate, it is an external force
according to the forced vibration theory. The material is aluminum. 4) Soul column: 11 11 ▼
Connect the vibration of the top electrode thin plate to the 12 back electrode thin plate. The
material is aluminum. 5) ▲ 12 極 back electrode thin plate: 11 11 に よ り due to the vibration
from the soul pole 11 11 生 じ An out-of-phase with the top electrode thin plate is caused to
cause negative interference. It is only in contact with the soul column but not in one. The
material is aluminum. 6) 16 16 f Holes: In the case of one layer, the sound absorbing type sound
shielding screen is in ▲ 11 だ け only in the front electrode thin plate, but in the case of a twolayer sound shielding screen ▲ 14 な い in the back electrode thin plate. In the case of a twolayer sound shielding screen, it serves to transmit sound through one layer and to propagate to
two layers. 7) {circle over (19)} knitting net: At the same time, in order to increase the tensile
strength of the sound insulation screen as a cloth, it becomes the side wall of {circle over (17)}
cell space. Material: Aluminum material 8) {circle around (17)} Cell space: ax b x c dimensions,
{circle over (11)} Forced vibration is carried out by the top electrode thin plate and {circle over
(12)} back electrode thin plate . 21) Polyethylene film: has a function of reflecting transmitted
sound that has not been erased, and has a structure in which it is bonded to an aluminum fiber
layer. The specification of the two-layer structure is applied when the sound insulation
performance is required more strictly, but it is also possible to further stack layers depending on
the conditions used. About the material (1) Aluminum fiber layer (2) Front thin plate, back thin
extraction (3) Soul pole (4) Mesh net, spacer These are made of aluminum material, but this is
replaced with titanium, stainless steel metal Can also respond. In particular, coated paper and
polymer resin materials are also possible, if the environmental conditions used are acceptable for
the front plate, the back plate and the column.
FIG. 5 shows data corresponding to the aluminum material in the embodiment. The sound
insulation rate at each frequency is a value satisfying the use conditions.
Sound insulation system layout speaker back noise canceler sound absorption sound insulation
screen diagram resonance · phase shift curve center frequency · sound insulation ratio diagram
Explanation of sign
1. Generated sound sensor microphone 11.
Front electrode thin plate (one layer) Amplifier controller 12. Back electrode sheet (one layer) 3.
スピーカー 13. Table electrode thin plate (two layers) 4. ケーブル 14. Back electrode thin
plate (two layers) 5. Sound absorbing sound barrier 15. Soul pillar 6. Portable toilet 16. f-hole 7.
Speaker back 17. Cell space 8. Sound conduction part 18. スペーサー 9. Same sine wave
speaker 19. Hen net 10. Sound absorbing sound insulation 20. Aluminum fiber layer 21. ポリエ