DE4133407C2 - Arrangement for compensating the sound emitted by a vibrating wall - Google Patents

Description

The invention relates to an arrangement for the compensation of a vibrating wall of radiated sound on which at least one body sound vibration transducer is arranged, which the vibrations of the Wall detected perpendicular to the wall surface, at least on the side of the Wall facing the causal noise level, a large number of sounders are arranged distributed over the wall surface, which Can generate changes in their volume and through structure-borne noise Vibration sensor is controlled so that the by the vibrating wall caused volume changes in the air space in the Area around the sounder by that of the sounder in the same Volume changes caused area are compensated at the same time.

The use of anti-noise to cancel out unwanted airborne noise fields is well known. The principle is based on that the disturbing sound waves in the area to be protected can be detected and by means of anti-sounders, which have a rule Circle connected to the detectors, extinguished by interference become. A simple antisound generator in which the sensor membrane and the Anti-sound source are identical, for example, from the DE 28 14 093 C2 known. With such an anti-sound generator also basically the residual sound passing through a partition wipe out. Such applications would be e.g. B. in a driving or flight Stuff given in which there is a high level of noise on the outer cell. The natural self-insulation of the wall shields a large part of it riding off, with the insulation due to the wall in the upper frequency range is generally sufficient. Result in the lower frequency range however deficits. Another application would be e.g. B. in apartments ben, the apartment walls or ceilings also at lower frequencies zen only have insufficient sound insulation. An improvement in Sound insulation by increasing the wall weight is only possible to a limited extent, especially since an improvement of the insulation by 6 dB doubles the Wall dimensions required.  

There are also suggestions for active control of walls, taking one Wall-mounted vibration exciters are used to attach them to the wall lying sound pressure forces are neutralized. A disadvantage of this However, the system is the large seismic mass that is used to support the Reactive forces are necessary. In addition, the necessary re circles to instabilities, since the wall vibrations drop to zero should be valid and therefore only a small input variable available is available.

Furthermore, EP 0 390 560 A2 describes a device for noise oppression for a seismic vibrator, in which the of Compensate airborne sound emitted by a vibrator plate through loudspeakers is based on that controlled by a vibration sensor Regulation can be controlled. However, the vibration sensors sit on the actively excited vibrator plate; a transfer of this facility passive walls is neither mentioned here, nor would it be with the expensive regulation expedient.

It is an object of the present invention by a vibrating Wall radiated sound in a simple way, d. H. with minimal effort and thus to effectively compensate for the small size.

This problem can be solved by using the features of Pa tent Claim 1 trained arrangement.

In this arrangement, in contrast to known anti-noise systems directly the vibrations of the wall running perpendicular to the wall surface detected by structure-borne sound vibration sensors and thus the immediately controlled nearby sounders. The reinforcement as well Phase shift of the sensor signal is such that the vibrating wall caused volume changes in the airspace in the Be range around the sounder by an opposite one, from the so is compensated for by the volume change caused. Because of the natural  Chen wall insulation are on the immission side, d. H. the side of the wall, which has to be protected from noise, much smaller anti-noise vibrations necessary. This reduces the necessary sounders to others may experience the effect of the anti-sound on the wall be neglected above the sound pressure on the source side. Next This simplifies the control of the sounder on one simple proportional amplifier with filter correction.

Depending on the type of wall and the excited wall vibrations, the Sounders in front of the wall either through one or more structure-borne noise vibration sensors can be controlled. The distance between two neighboring The sound generator should be half of the smallest to be compensated Do not exceed sound wavelength; because the insulation of normal walls Frequencies below about 300 Hz, the The maximum distance between adjacent sounders is 50 cm. When out The wall sounder can be extended at equal grid intervals or weighted according to the wall vibration attached over the wall become. The smaller the grid spacing in relation to that to wipe out the sound wavelength, the greater the maximum achievable Sound cancellation.

In the simplest case, the individual systems can be made from structure-borne noise the sensor and sounder are autonomous; being an improvement tion of the effect can still be achieved in that the signals be neighboring systems to control each sounder included the.

Because the radiation of sound waves in corners or edges from each other approaching walls is difficult to predict, it can be useful be a sound generator installed in a corner or edge by meh Other structure-borne sound waves arranged on each of the adjacent walls control to control what their weighted sum signal is pulled.

It is also possible to derive the power from the sounder  moving walls, such as B. to pull in vehicles or aircraft. Here can it be z. B. act as an analog elevator mechanism as he is realized in wristwatches. Low frequency vibrations can also occur the wall can be used in an electrodynamic system generate electrical power, which is then stored and used Power supply of the sounder system can be used. Such The arrangement would then also be completely autonomous in terms of energy.

The invention is based on some, in the figures in part schematically illustrated embodiments described in more detail. It demonstrate

Fig. 1 shows an anti-noise system for a passive wall,

Fig. 2 shows an anti-noise system Actuated in resonance sound generator,

Fig. 3 is a wall surface with uniformly arranged anti-sound systems,

Fig. 4 shows a wall surface with linearly arranged anti-noise systems and

Fig. 5 shows an anti-noise system at a wall edge.

On the basis of the embodiment shown in FIG. 1, the mode of operation of an antisound system 10 is described. This consists of a sound generator 11 and a structure-borne sound vibration sensor 12 , for. B. an accelerometer. The antisound system 10 is attached to the wall side 14.1 of the wall 14 opposite the sound source 15 , so that the space adjoining it is protected from the residual sound passing through the wall. The sound field of the sound source 15 excites the wall to vibrate, the inner wall 14.1 radiating these vibrations. The perpendicular to the wall surface 14.1 wall vibrations are detected by the structure-borne vibration transducer 12 and controlled by the output signal of the sound generator 11 so that it just compensates for the sound radiation from the inner wall 14.1 in its environment.

In Fig. 4, the equivalent circuit diagram for an anti-noise system 40 is Darge, in which the sound generator 41 consists of a resonance oscillator with a piston 45 of mass m and the area A, a spring 46 with the Fe derkonstante c and a damper 47 of the damping constant k . This equivalent circuit diagram also applies in the simplest way to a loudspeaker or a vibrating plate. The piston 45 can be driven by a force transmitter 48 with the force F (t) (t = time). At the wall 44 to be compensated, a structure-borne vibration sensor 42 , z. B. an accelerometer that receives the normal wall acceleration (t). Such a resonant sound system 40 is particularly advantageous for compensating for periodic noise or with pronounced wall resonances. The resonance frequency ω _{0 of} the resonator is tuned to the noise frequency to be canceled. In order to make do with minimal force F (t) and thus smaller size, the control regulation for the force F (t) is

F (t) = γ ₁ s (t) + γ ₂ (t) + γ ₃ (t)

where γ ₁ : γ ₂ : γ ₃ = c: k: m should be.

(t) is the normal vibration speed and s (t) is the vibration vibration hit the wall. (t) and s (t) can be integrated from the Be acceleration (t) are formed.

In order to cover the entire frequency range according to this working principle, several sound systems 40 are used which are tuned to different resonance frequencies, each of these systems only compensating for the near-resonance frequency band.

FIGS. 3 and 4 show various arrangements of anti-sound systems in broad wall surfaces. In Fig. 3, the anti-sound systems are distributed in uniform grid 50 with intervals of less than λ / 2 of the smallest to compensating sound wavelength over the wall surface. When using linearly arranged sound generators, the anti-noise systems 60 according to FIG. 4 can also be arranged next to one another at intervals of less than λ / 2.

In Fig. 5, an anti-sound system is illustrated in a wall edge 70. This consists of a sound generator 71 and two normally in the colliding wall surfaces 74.1 and 74.2 attached structure-borne vibration transducers 72.1 and 72.2 . As a control signal for the sound generator 71, the weighted sum signal is used to Körperschallschwingungsaufnehmer 72.1 and 72.2.

Double or multiple walls are used in the same way as single walls acts. In each case the wall surface facing the side to be protected ner double or multiple wall is ge with anti-noise systems of the above showed kind provided.

Claims (7)

1. Arrangement for compensating for the sound emitted by a vibrating wall, on which at least one structure-borne sound transducer is arranged, which detects the vibrations of the wall perpendicular to the wall surface, with a plurality of sounds at least on the side of the wall opposite the causal sound load donors are arranged distributed over the wall surface, which changes in their volume can produce and controlled by the structure-borne noise taker such that the volume volume of the air space in the area around the sound generator caused by the vibrating wall changes caused by the volume caused by the sound generator in the same area Compensated at the same time are characterized in that one sound generator ( 50 , 60 ) at a maximum distance of λ / 2 is evenly surrounded by further sound generators, where λ is the smallest of the sound wavelengths to be compensated and that the sound generator is a wall are designed as a resonator ( 41 ) with the vibration mass m, the damping k and the spring constant c, which corresponds to the normal wall acceleration (t), the wall vibration speed (t) and the vibration travel s (t) by the control force F (t) - γ ₁ s (t) + γ ₂ (t) + γ ₃ (t) is driven, the coefficients γ ₁ , γ _{3 being set} according to the relation γ ₁ : γ ₃ = c: m. 2. Arrangement according to claim 1, characterized in that the Ab stood from two adjacent sounders ( 50 , 60 ) at most 50 cm be. 3. Arrangement according to claim 1 or 2, characterized in that at least some of the sounders designed as resonators ( 41 ) of a wall have a resonance frequency which is tuned to a wall resonance to be compensated or a dominant working frequency. 4. Arrangement according to one of claims 1 to 3, characterized in that the resonators ( 41 ) are tuned to different frequencies. 5. Arrangement according to one of claims 1 to 4, characterized in that several structure-borne sound vibration sensors ( 72.1 , 72.2 ) are assigned to a sound generator ( 71 ) and are arranged in the vicinity thereof and the sound generator is controlled by the weighted sum signal of the structure-borne sound vibration sensor. 6. Arrangement according to claim 5, characterized in that the Kör perschallschwingungsaufnehmer ( 72.1 , 72.2 ) on different, in a corner or an edge abutting walls ( 74.1 , 74.2 ) are net angeord. 7. Arrangement according to one of claims 1 to 6, characterized in net that the structure-borne sound transducer and the sounder one form a compact unit.