AF..could just be your intercom squelch setting, I guess. That said, I found the ANR S1 mic level to be on the high side as it came from the box. I had to reduce the mic gain of my IC A210 transceiver (easy software setting) to optimize the S1 mic performance (it's a conventional noise-cancelling mic, I believe). You don't want to be running any more mic gain than necessary.
It's quite interesting that the cockpit noise cancellation in the headset is so effective that there's more cockpit noise on the mic sidetone when transmitting than when flying along with no radio activity. I also like the 'recompute' facility on the S1 ANR as it optimizes the headset cancellation under e.g. different engine power settings. It's great even if you don't re-compute but touching the button on the left earcup gives few welcome dB attenuation relative to the other big name ANR headsets.