some pluging to cut out high pitch noise

Hello Alfa-Alsa geeks!

I have a need.

I have either very sensitive mic or problematic sound card.

I catch a bit of a noise, that sounds like my PC coolers(which are not 
too loud...)

I want to cut noise in VOIP services, so apps which cut out noise post 
factum - are not an option.

Some are Alsa, some are Pulse.

 From what I could google on Alsa plugins - there don't seem to be 
anything that can filter out noise real time.

Any suggestions?

Thanks!

Dmitri