kevinrich47 wrote: > Thank you Tim,What I want is not change voice for single app,but for > all application on the machine, > I have consider Virtual Audio Cable,But the price is not > affordable for me. Oh, come on! There's a free version with some features limited for you to try out, and the full version is only $30. If you have not done audio drivers before, it will save you MONTHS of frustration. If you are working on Vista, you can write a Local Effects Audio Processing Object (LFX APO) to do this. This is a user-mode DLL that lives in the the audio engine process. There is a sample in the WDK in src\audio\sysfx. It's a little bit tricky to get one installed to begin with, but there are documents available to help with that. -- Tim Roberts, timr@xxxxxxxxx Providenza & Boekelheide, Inc.