I currently have a high quality microphone that I am powering from a relatively noisy 8V source, like that shown below. It has a built-in amplifier, and doesn't require any amplification. It just needs power and a bypass capacitor in place, and it handles the rest.
In order to resolve the noisy power supply, I temporarily removed it, and power the circuit off of a 9V battery for now, which has resolved a fair amount of the noise issue. Now I have a new problem: I need to power two of these microphones off of the power supply, and I'm now encountering cross talk.
So, ultimately I am trying to decouple the microphones by balancing the circuit by halving the resistance of the biasing capacitors, and placing a second resistor of the same value in series with the mic between MIC- and GND. Additionally, I'm putting some Schottky diodes in place in hopes they will also help block cross talk. Finally, I'm just putting a simple LDO voltage regulator (8VDC) at the power source, and following it with a large bypass capacitor to further aid in power source noise rejection. Will this circuit work, or does anybody have suggestions for improvements or different approaches to resolving this issue?