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DEICON’s patented, feedback-controlled, electronic acoustic absorber is highly effective in reducing the boominess of sound at frequencies corresponding to offending (coloring) standing waves of an enclosed space, e.g. a room. The controller which is realized by a tunable, op-amp circuit can be tuned to one or two, low-frequency resonant mode(s), add damping to that (those) modes and thus abate the boominess and rumble of sound at that (those) resonant frequencies. The actuation is provided by a 10 inch (250 mm) speaker. A microphone built into the speaker is used for feedback control. The size of the active tuned acoustic damper is the size of the speaker which is by far smaller than reactive low-frequency dampers. |
Considering the ineffectiveness of sound absorbing material at low frequencies, standing wave (acoustic resonance also known as coloration) problem in enclosed spaces has traditionally been addressed using large reactive damping/absorption devices such as Helmholtz resonators or quarter-wave tubes. Issues with these low-frequency absorbers are a) their large size, b) once tuned they can not be retuned, and c) when absorption at multiple frequencies is required a number of these absorbers tuned to different frequencies should be used. An alternative to the use of low-frequency reactive dampers/absorbers is active tuned damping/absorption. This feedback controlled solution which can be viewed as a low-frequency ‘active tuned acoustic damper’ or ‘active tuned acoustic absorber’ effectively adds damping to a low-frequency standing wave (resonance/coloration). |
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Home | Contact DEICON E-trap(TM), An Electronic Bass Trap Tuned Absorbers/Dampers Active Damping of Low-frequency Boom and Rumble Noise (PDF) |
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