Trying to compute Biquad Coefficients for use in a codec chip TLV320AIC3100.
Bass Shelf(boost and attenuation) work as expected. Treble Shelf attenuation works as expected but Treble Shelf boost is being weird in the sense that the amplitude difference between non treble frequencies and treble frequencies is as expected (Say 10dB) but instead of the overall gain being +10dB at treble frequencies, it ends up being +3dB(ish) and non treble frequencies end up being -7dB (instead of 0dB).
Used the TI BiQuad Calculator tool and also the tool here
Don't know where things are going wrong. Any guidance is much appreciated. Thank you.
Used the formulas from p3 of this PDF
// Coefficients from the Calculator N0 2.336268076 N1 -2.773236549 N2 1.01094234 D1 -0.680740702 D2 0.254714569 N0_Real 2.336268076 N1_Real -1.386618274 N2_Real 1.01094234 Scaling Factor 2.336268076 (Max of the above 3 values) Range 32767 (Fixed for the Chip - 16 bits) Digital Coefficients N0 32767 N1 -19448 N2 14179 D1 11153 D2 -8346
- Sampling Frequency: 44100
- Treble Shelf Center Frequency: 7kHz (to get required boost/attenuation at 10kHz)