Active Tuned Acoustic Damper

Active Tuned Acoustic Damper

DEICON’s patented, active acoustic damper/absorber is highly effective in abating undesirable low-frequency tonal noise. Applications of this acoustic treatment include, but not limited to, dampening a resonating standing wave (acoustic mode) in a small room (such as a recording studio or a cabin in a yacht) or mitigating acoustic instability in an industrial combustor (boiler, heater, gas turbine, etc.).

The controller which is realized by either a tunable, op-amp circuit or a high-speed computer (digital signal processor) can be tuned to:

  • one or multiple, low-frequency resonant mode(s) to add damping to that (those) modes and thus abate the boominess and rumble of sound at that (those) resonant frequencies, or
  • frequency(ies) corresponding to a driving perturbation (such as the blade passage frequency of a fan) and absorb sound at that (those) perturbation frequencies.

The actuation is provided by a loudspeaker and the sensory information is supplied by either a microphone or a dynamic pressure sensor.

 

The size of the active tuned acoustic damper/absorber is the size of a loudspeaker which is by far smaller and lighter than comparable passive low-frequency dampers/absorbers targeting the same low frequencies.

 

The application of this technology in adding modal damping to small rooms (listening rooms, recording studios, home theaters) is licensed to Modular Sound (the reputable manufacturer of Bag End professional grade speakers) which makes electronic bass traps, with the trade name E-trap(TM), based on this technology.

Industrial applications of this technology, due to their uniqueness and need for customization, are being implemented by DEICON.

Considering the ineffectiveness of sound absorbing material at low frequencies, treatment of sound at these frequencies has traditionally been done using reactive damping/absorption devices such as Helmholtz resonators, perforated acoustic liners, 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. DEICON’S active tuned acoustic damping/absorption solution is a smaller and more effective alternative to the passive solutions, for low-frequency sound absorption applications.