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Popping Noises with the ADAU1701 and SimgaDSP v3.11

Question asked by jzagnit on Feb 9, 2016
Latest reply on Feb 9, 2016 by jzagnit

I have a speaker platform which uses the ADAU1701 and has it's processing flow being created using SigmaDSP v3.11 for 64-bit OS's. I'm  having trouble with popping noises and re-arranging the signal flow to try to  eliminate the popping noises.  The popping noises stem from a potentiometer  which is connected to a MCU.  The MCU reads the pot voltage and changes a shelf slider inside of the 1701 appropriately.  There is a variable HPF in the signal  path inside the 1701.  If that slider is near the end of the signal path, the  pop noise is present.  If the slider is near the start of the signal path, the  pop noise goes away.  If a DC block is added at the start of the path, the pop  noise also goes away, but the signal is attenuated by 10 dB.  I'm not clear on why the DC blocker causes the 10 dB of attenuation. If I re-arrange some of the blocks, the whole thing becomes unstable.  Any help here would be greatly appreciated! Thanks.