Tascam us-144mkII

Sat Apr 9 07:21:45 UTC 2011

Am Sat, 09 Apr 2011 06:35:59 +0200
schrieb ailo <ailo.at at gmail.com>: 

> Specifically, I would be interested to find out if one can get 24 bits
> and 48kHz out of a card.

You can get that out of the Alesis io|2, USB 1, duplex, 24 bit stereo, 48 kHz. It uses actual 24 bit sample format ... so that's 3 B * 2 * 2 * 48000 = 563 KiB per second of payload data that fits well into the limit of USB 1.1 (12 MBit/s = 1464 KiB/s), giving space for whatever overhead is present.
But yeah, anything more than that gets really tight. You could have a card with 4 recording channels and 2 playback ... that would be 844 KiB/s ... but then, I don't know how much overhead you have with USB audio and also I'd have to review how duplex operation actually affects the available data rate.

Also, looking at the devices that are there, USB1 audio for linux goes up to 24 bit stereo, duplex. And yes, USB 2 devices seem to be sparsely supported. For multichannel recording I got a FireWire device... and FireWire audio can be a bitch to get working right (building a good computer setup).

> Stereo cards work the best. There are a few multichannel cards that work
> too, but out of those, usually only those will work well that have
> specific drivers. 

The one that seems to work nowadays is the Edirol UA-101, the USB2-sister of my FA-101. There is a driver in ALSA, snd-ua101, that reportedly delivers multichannel work. But what's missing is the software control for the direct monitoring mixer. But then, on my FA-101 setup, I don't use direct monitoring from the box ... we have an analog mixer and separate headphone amp for that, the recording interface is just connected via the inserts on the channels (only the send part).

Alrighty then,

Thomas.
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