Reply bounced back. Resend. People have been debating on where AEC should go for a long time. The advantage of doing AEC inside audio API is exactly what you mentioned - everyone gets it without additional programming. But doing AEC in application level also has advantages. For example, application can easily get full control over it and developers can improve/update it easily. I think one important reason for Vista to do AEC in application level is AEC on PC is still evolving in a very fast pace. Many AEC customers would like to do additional programming work if they can get AEC quality improved. As a matter of fact, both MSN messenger and SKYPE are using AEC in application level in XP even though XP provides AEC functionality (aec.sys) via DSound. Chao He Microsoft Corporation From: wdmaudiodev-bounce@xxxxxxxxxxxxx [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Tim Roberts Sent: Wednesday, October 04, 2006 10:20 AM To: wdmaudiodev@xxxxxxxxxxxxx Subject: [wdmaudiodev] Re: AEC in Vista Shuba Iyer wrote: AEC and microphone array processing in Vista are application graph features. So it is up to the application to use the feature or not. You know, the more I think about this statement, the more I think this position is completely wrong. AEC is perhaps "the" canonical feature that one would want to use globally. As a user, I'm not going to think about AEC as an application add-on. Instead, I'm going to think about AEC as an attribute of the microphone array. If I have installed some kind of AEC, then I want echo cancellation in every application that uses that microphone, whether it be wave, DSound, or WASAPI. I've been using Sound Recorder as an example, but that's the wrong example. With the policy you have described, there is no way to use an AEC-enabled microphone with NetMeeting, which is one of the apps where I would most want echo cancellation. In fact, if I am a vendor supplying my own AEC DMO following your model, there is no way to have it get used by any applications other than the ones I have written myself. That ain't right. Have I misunderstood your position? -- Tim Roberts, timr@xxxxxxxxx Providenza & Boekelheide, Inc.