Other Parts Discussed in Thread: LM358
Would you be able to review the attached schematic? It's largely taken from the TPA6166A2 EVM. "SPKR" and "MIC" are expected to be line level, with a high-impedance single-ended load on MIC. ESD diodes added at the TRRS jack as the system is expected to be used in a poorly-controlled environment. SCL and SDA pull-ups to 1.8V are elsewhere in the schematic.
There's a low-pass filter on SPKR as there may be noise sources in the system >10kHz and this system is mainly to handle speech only. The audio source is mono.
For summing the microphone outputs of two or more of these devices, what do you recommend--10k series terminations on each, connected together at the input to an opamp?