TLV320AIC3256: How to tune TLV320AIC3256’s Analog mic SW gain or EQ?

Hi Hank,

Is this the expected frequency response of the microphone? I hope you have checked the high-pass filter (HPF) after the decimation filter and confirmed that the low frequency attenuation is not caused by a large cut-off frequency setting in the HPF.

I am assuming you will be using the miniDSP and PPS for equalization. To equalize and gain-up the response that you have shared, you can use a combination of equalizers and bass shelves. A bass-shelf with positive gain (say around 3-6 dB at around 500-700 Hz) can be used to boost the signals from about 300 to 1/2 kHz. Equalizers can be used to cut gain at ~9 kHz and provide further boost to frequencies in the 1-3kHz band. It is recommended not to use high gains in any one stage and use multiple low gain stages to get the required boost.

Digital gain (using digital volume) can then be applied after EQ to increase the overall signal level.

Best Regards.