Alesis io 2 express (was: cheap usb-audio-interface)

[Thomas Orgis]

Am Thu, 10 Feb 2011 22:25:43 +0100
schrieb mentoj dija <mentoj_dija at gmx.de>: 

> I got an Alesis io2 express audio interface now. after playing around 
> with the jack-parameters, it's working with this preferences (look at 
> the attachment). but with lots of x-runs and this error-messages:

Don't blame the interface... I got an io|2 (without express, that's the same hardware just with digital SP/DIF ports still present) and I can do

jackd -R -d alsa -d hw:1,0 -r 48000 -p 128 -n3
(that is, period size of 128 compared to your 512, period count of 3 instead of your 4, rate 48000)

on my Thinkpad X200 without trouble, loading ardour2 and playback of a 7-track Project does not yield a single xrun. Also switching to your sample rate of 44100 does not seem to bother the system. But: On another laptop I once used, this setting would not work at all. It would be full with xruns all the time, if not worse. That machine needs a setting of 3*1024 to do reliable recordings (so, no realtime processing work, except delay effects:-/). That other box is also similary bad at getting reliable recordings with the internal audio, so USB really is a secondary factor.

So, there could be something you can do to optimize your system setup (realtime / lowlat kernel, stop any background processes -- I once had some cron job scratching all over the disk and grinding jackd to a halt on that other laptop), but it might be that your hardware doesn't allow for low-latency recordings. Your computer that is -- that is my main message; your problems most probably lie on the other side of the USB cable, not the io|2. Does it at least work at 3*1024 periods?
For a quick system configuration check, it may be good to just boot an AVLinux live system and check how well the interface works for you there. If that's better, you know that you should be able to tweak your installed system likewise.


Alrighty then,

Thomas.
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