Yatie,
Ahhh!!! You don't know how good it is to hear from someone else who has
experienced this problem!! Actually, I don't anymore, but did when I had a
BCI soundcard with an ESS chip....my guess is that you have a Sounblaster
compatible card with the ESS chip. Unfortunately, I tried everything,
especially when the darn sound started working correctly spontaneously one
day. Could never get it to work right though in a repeatable or consistent
way, and most of the time, it didn't work at all.
I finally gave up and got a true Soundblaster card. Haven't had a problem
since.
The machine gun (or as I called it, idling diesel locomotive) sounds is the
frequency "hanging" on whatever was the last nano second of transmitted
sound before you let go of the "push to talk button".
Wish I had a better solution for you, but I think your best bet is to get a
Soundblaster (or a clone card that someone on the list knows to work).
Good luck,
Jon