If you use the factory settings you will need to adjust them to achieve best results. I got a lot of feedback on my first flight.
Here are my settings that may help you get in the ball park.
HEADPHONE LEVEL 000 (slave to volume control)
MIC 1 SQUELCH 009 (Bose x)
MIC 2 SQUELCH 012 (Flight Com)
INTERCOM LEVEL 030
SIDE TONE 000 (slave to volume control)
MIC XMIT option 1,2,both (if both, then both mics will xmit when either 1 OR 2 is pushed. Open mic will pick up cabin noise.
More about it here.
http://www.vansairforce.com/communit...=SL40+SETTINGS