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how to implement feedback control with a loudspeaker module in COMSOL ??
Posted 18.12.2014, 07:23 GMT-5 General, Acoustics & Vibrations 1 Reply
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Now, i'll trying to implement 'Direct impedance feedback control' used for the noise reduction method in an electroacoustic absorber system. Here, the velocity and pressure information of the loudspeaker diaphragm are required for the 'direct impedance control'. Using these information, the control voltage is formed and applied to the loudspeaker's terminal, then the loudspeaker can absorbs and reduces the noise in a resonance system, for example duct system.
Now, the electroacoustic absorber system has been already implemented exprimentally, but I'm confused that how to implement numerically using COMSOL software.
The most confusing point to implement this system through the simulation COMSOL process, how to form the control voltage. Because the magnetic part where the control voltage should be applied to the voice-coil is analized in advance of the structure & acoustic part where the diaphragm velocity and pressure information are obtained in 'Loudspeaker module of COMSOL'. That is, the problem comes from the fact that diaphragm velocity of the loudspeaker is necessary for the control voltage in magnetic part, the velocity is obtained after magnetic part.
So, I set the simulation setup; a loudspeaker is placed at the end of the duct and the external noise pressure source is generated at the other end of the duct. In order to get the diaphragm velocity and pressure information in front of the open-air loudspeaker for the control voltage will be used in the magnetic part, the structure & acoustic part of the loudspeaker is simulated first. Then, the control voltage formed with these velocity & pressure information is applied the loudspeaker (i.e., becomes electroacoustic absorber). Finally, megnetic and structure and acoustic part of the electroacoustic absorber are simulated.
But, the simulation results of the duct + electroacoustic acoustic system are not consistent with my expectation at all.
Question)
1) My simulation process as I said above is wrong?
2) Or Sequence solver is needed??
Please help me !!
Hello Youngeun Cho
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I would like to know the principle of modeling the control voltage as well.
Thank you!
K.