distorted

I asked this before but never got an answer. My live audio feed of MIA airport seems to have distorted audio (not a humm, but some kind of distortion), especially on the lighter signals. If the audio is full quieting into the scanner, and hence into the computer, the distortion goes away. I...

I'm trying to monitor Fire dispatch in Austin/Travis county. I'm using a BCD996T, programmed for P25, defalt lvl, NFM mod. I'm able to hear, but the computer voice comes across very distorted. any ideas on how the clear this up? thanks for the help.