I have the same request, I like to tun Stereotool at my media center, so winamp, youtube, power dvd etc all must go true Stereotool, not only winamp.
I found software called Viper. Although it's audio features are way less advanced then stereotool, the way it is setup as APO seem ideal. Would like to see stereotool implemeting that.
Quote from website:
http://vipersaudio.com/blog/?page_id=85
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ViPER4Windows is an “APO”. APO stands for “Audio Processing Object”. APO is designed by Microsoft. It is an audio processing framework that can be loaded onto any sound card.
Comparison between APO and SRS Virtual Sound Card:
APO - SRS Virtual Sound Card
Supported system Vista or above - All
Global effect Yes - Yes
Stability Very stable - Easy to get BSOD
Compatible with other effects All - Only specific effects
System compatibility Very good - Poor
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