I hope this is the correct forum for this question. If not, could
some one direct me to a better one?

I'm looking for a layman's definition of the differences between
squelch and gain. I ask this because I've recently purchased a new
aviation headset which doesn't impress me with its performance, but
I'm new at this so I'm pretty sure I have to mess with the headset's
gain (it's adjustable) and the radio's squelch. The intercom that the
headset gets connected to is voice activated, but I can't seem to get
things set where the microphone doesn't pick up the background noise.
Plus, the sound is very muted, although that might simply be a
function of how close the mike is to my mouth. I believe squelch
could be set to the proper level of voice activation, but where does
the gain figure in?

Could I get some pointers on this?

Thanks