Nantonos:
MarkT:
With no information on your circuitry there's no way to judge where the analog noise might be coming from.(check the attachment to the original post, for the wiring)
Well that (apparently) tells me only that you are using some sort of microphone module, not a microphone directly - is there information on that unit?
Secondly you seem to be running logic signals well away from the ground connection - all logic signals (being super-fast) ought ideally to run close to a ground line to keep stray inductance under control and to provide a return-path for the transients (otherwise you force that return path to be any near-by wire) - bundle the power supply and signal wires to the Xbee together for instance. And keep them fairly short.