Yes, that would cause Windows to use your KSPROPERTY_AUDIO_VOLUMELEVEL instead of injecting a software volume APO, yes. You would then control the default volume, as well as the min/max/step size. This is usually used to control a hardware amplifier below the driver; it is not meant to enable kernel-mode digital signal processing, which is risky and entails floating-point state recovery etc. Perhaps a simpler option is to change your pin category to something non-microphone-ish. The article says “Of course, the INF file that installs an audio adapter driver can override the operating system's default volume settings with its own default settings” but I don’t know details, or even whether that is still true. From: wdmaudiodev-bounce@xxxxxxxxxxxxx [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Tim Roberts Sent: Wednesday, December 19, 2012 2:51 PM To: wdmaudiodev@xxxxxxxxxxxxx Subject: [wdmaudiodev] Re: Audio AGC? Matthew van Eerde wrote: What version of Windows are you running on? See the chart here: http://msdn.microsoft.com/en-us/library/windows/hardware/ff536251(v=vs.85).aspx<http://msdn.microsoft.com/en-us/library/windows/hardware/ff536251%28v=vs.85%29.aspx> That's the key reference point I was missing -- enormous thanks for that. I'm currently testing on Win 7, as is the client. I do advertise myself as a microphone, so the system is applying a +30dB boost. So, am I right in thinking I can solve my problem by supporting KSPROPERTY_AUDIO_VOLUMELEVEL? -- Tim Roberts, timr@xxxxxxxxx<mailto:timr@xxxxxxxxx> Providenza & Boekelheide, Inc.