I doubt you can do what you want to do, just because of the hardware issues. There would have to be a clock sync stream coming from the PC and controlling the audio conversion process on the USB device. That isn't trivial. Usually this sort of thing is accomplished by hardware word clock inputs and outputs on the audio devices. - Andy _____ From: wdmaudiodev-bounce@xxxxxxxxxxxxx [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Faby, Paul Sent: Wednesday, March 30, 2005 9:25 AM To: wdmaudiodev@xxxxxxxxxxxxx Subject: [wdmaudiodev] sync clocks of two filters Is it possible to lock the clocks of two filters? I'm trying to support multiple usb audio devices(the same type of device) inside of my ASIO interface(wraps directks). I was hoping that I would be able to (from user land) be able to create the render and capture filters of the two devices and lock there clocks together. Is this possible? If not, is it possible for me to write an avstream driver that would get a hold of the two devices and lock their clocks? Thanks paul