30 Aug
2003
30 Aug
'03
9:45 a.m.
Mannr(a)uwaterloo.ca 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