The gentle LF rolloff set by the choice of C value is not going to "cut off" anything. Please read up on single pole filters. If you need a hard cutoff below a specific frequency, the easiest place to get that is the highpass filter available on most field recorders, or by filtering in an audio editor afterwards.
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Re resistor values, the documentation of the SimpleP48 circuitry is superb, and covers all of this quite well. I did a little experimentation with my PUI AOM5024 capsules, but mostly to ensure that I wasn't exceeding the voltage and current ratings for the capsules. I ended up choosing 82k for resistor. I've built two simpleP48 pairs so far with AOM5024 capsules. In one pair, I used 4.7uf caps. In the other pair, which is now semipermanently installed outside, I used 2.2uf. There's still more than enough low-end there.?
