How can I get a voice key function into a VB6 application?

I want sounds, picked up by a microphone plugged into the computer's audiocard mic input, to trigger an event procedure in VB6.
I don't need anything fancy like voice or word recognition, just that when incoming sounds get above some audio level it instantly triggers an event procedure that I can use for reading timer etc.

How can that be done?
Is there any control that can do that?
Any OCX?
All hints appreciated, thanks,

Sverk