[LAU] Problem with Lexicon Omega USB-Audio device

Susanne Schneider susemuse27 at gmx.de
Sun Jun 17 09:04:36 EDT 2007

hi, thanks for answering, no, the crackling does not occur everytime, 
this seems to depend on the system load - I'm able to run smooth 
recording sessions using two stereotracks in Ardour with one reverb 
but last night I learned from the internet - mainly from the listhistory 
- that things are obviously some more complex to determine - inter alia 
stability of audioprocessing also seems to be a question of interrupt 
settings and priority - so I fear my question just can't be answered in 
that simple way I would wish - thank's anyway :-)

Johannes Mario Ringheim schrieb:
> Susanne Schneider wrote
>> using two of four possible inputs with jack I'm able to run my 
>> standard apps like Ardour, Rosegarden, Hydrogen, Bristol, Qsynth with 
>> a minimal latency of 128 Frames/Period and 4 Periods/Buffer at 44100 
>> Hz (=11,6 ms) without xruns -
>> BUT(!): sometimes (seems to depend on the extend of use of plugins 
>> and synths), during recording after some minutes from the start an 
>> increasing crackling-noise occurs which makes my record unusable - 
>> jack reports no xruns at all!
> i had a similar problem with an sblive, it started crackling like you 
> describe each 30 min or so depending on the jack settings. a post to 
> the jackdevel list revealed that the card was really working at 48kHz 
> all the time, and resampling in the case of 44, 22 or any other sample 
> rate. so, does the crackling occur periodically? if so, you might want 
> to try with 48, 96 or some other sampling rate.
>> I then have to stop and close my apps, restart jack and start all 
>> new... a tedious biz...
>> Searching the Internet I learned that my Audiocard may not be 
>> "devicecompliant" in terms of USB - whatever this means.
> afaik the linux kernel supports any "devicecompliant" usb card, so if 
> it's not there's a fair chance you'll have problems.

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