I can't speak for Win Amp - but I do know that this RealPlayer, RealOne Player, RealJukebox plugin does allow you do just that. I was the Product Manager for this goodie in another life:
http://www.real.com/accessories/?prod=s ... cais,rcarj
I use Win Amp for my background music, but run a non-PC based show. Win Amp ROCKS! I gave up on Real products across the board about 18 months ago, just too darn buggy and take up too much resources. Win Amp is bulletproof I've found and when I'm doing a show I don't have time to deal with GPF and corrupted databases.
One cool twist to Surreal.FX - I seem to remember that Surreal.FX does NOT need Real products to work - and that it will work with any program - it is a stand alone application and not a true plugin. Real was so protective of the Player core when this was developed so it had to be worked around to make it go. You can try with the free version download. It's not spyware, adware, etc. etc. etc. etc.
I'm sure a Win Amp plugin out there does it, there are tons of them but this was one I knew off the top of my head. One other pearl - NOTHING and I mean NOTHING has been done with this software since early 2001. It is old -- but when it was released it blew away anything WinAmp had to offer - that was a key for us in development. The same company that did this also did work on the Microsoft Plus Pack for Windows XP...