Hallo, Mannr@xxxxxxxxxxxx hat gesagt: // Mannr@xxxxxxxxxxxx wrote: > 1. Is there a "standard" USB interface for audio? For example, will newer > devices, like "Audiophile", "MobilePre", and "Transit" from Maudio work > using some kind of standard interface as the "Duo" and "Quadro"? Well, there does exist a standard for USB (1.0) audio interfaces. I don't have the link handy but it is online if you google for usb audio standard. But then not all USB audio devices follow this standard by the word... > I've seen references to "ASIO" or somesuch. Does that mean they > will all function with standard drivers? ... and it seems that some with "ASIO" support don't follow it. The reason, as far as I understand it, is that a fully standard compiliant device is recognized by MS-Windows as such a device and then MSW installes its own drivers. But ASIO isn't compatible with standard Windows drivers, so manufactures cheat Windows to not install its drivers, so they can install their ASIO drivers instead. Some devices, like the Edirol UA-20 even have a switch to choose a standard mode and the "ASIO" mode. But then there also are ASIO capable USB devices like the M-Audio Quattro, that don't need any quirks at all. The good news is, that it seems to be not too hard to adapt to that situation by reading the output of lsusb and change ALSA's usbquirks.h file accordingly. That's why Clemens Ladisch always asks for lsusb output when someone on alsa-user has gotten hold of a new device. The other problem is firmware: Several devices need to upload a firmware to their progammable hardware before becoming fully functional. This has to be done on Linux, too, and certain functions have to be written for each new device that needs it. So the future, as always, is uncertain. > 3. If mixers do allow level adjustments above, which USB devices have mixers? > > People have claimed that Edirol UA-1A doesn't have a mixer. > How about Edirol UA-3D? > What about Maudio Audiophile, MobilePre, Transit? I had or have the M-Audio quattro and the Edirol UA-20. Both don't have a mixer. The M-Audio Audiophile PCI has a mixer, but that doesn't work under OSS-emulation. The SBLive has a functional mixer. > 4. Is it usual to have stereo mic inputs on sound cards? Not every card has stereo mic inputs. Not every card has mic inputs at all. The Quattro has four mono inputs, switchable for line and mic level. > 5. Finally, I noticed that many of the Maudio USB products, like Audiophile, > Quatro and Duo, need external power. The funny thing is that they > need 9 VAC. AC voltage! What's up with that? I was expecting > some standard DC voltage, eg., 9 or 12V, suitable for mobile use. I guess they should come with appropriate adapters for your region. But the most mobile solution is USB-powered. ciao -- Frank Barknecht _ ______footils.org__
