Mannr@xxxxxxxxxxxx wrote: > 1. Is there a "standard" USB interface for audio? Yes. This is the reason why there is one driver (snd-usb-audio) for all kinds of USB audio devices. (If you're curious, the specifications are available at <http://www.usb.org/developers/devclass_docs>.) > For example, will newer devices, like "Audiophile", "MobilePre", > and "Transit" from Maudio work using some kind of standard > interface as the "Duo" and "Quadro"? The newer M-Audio devices are compatible to the USB Audio specification after the driver has loaded a device-specific firmware into them. Such a loader doesn't yet exist for Linux. > I've seen references to "ASIO" or somesuch. Does that mean they > will all function with standard drivers? ASIO is a driver architecture introduced by Steinberg to overcome the limitations of Microsoft's MME architecture from Windows 3.x. It isn't relevant to Linux. > 2. What do the [alsa|au|x]mixer controls do? ALSA simply exposes the controls of the hardware, so the number/type/meaning of the mixer controls depends entirely on the capabilities of the device. > I could not find this information, neither in docs from Maudio nor in alsa > docs. Please point me to the appropriate place if this is written down > somewhere. What I am looking for is a "block diagram" showing where > the amps and level controls really are. You'd have to ask M-Audio for this (or other M-Audio users). > Or, perhaps some devices have mixers, but USB control code is not written? The USB Audio specification defines the mixer interface, too, so this shouldn't be a problem. HTH Clemens
