[LAU] Problem with Lexicon Omega USB-Audio device

hello list, when plugging in my LexiconOmegaStudio USB-Audio/Midi Interface to my Laptop (Asus A4K, Mobile Athlon 64 1.7Ghz, 512 MB), dmesg tells this: ------------------------------------------------------------------------------------------- usb 2-1: new full speed USB device using ohci_hcd and address 3 usb 2-1: new device found, idVendor=1210, idProduct=0002 usb 2-1: new device strings: Mfr=1, Product=2, SerialNumber=7 usb 2-1: Product: Lexicon Omega usb 2-1: Manufacturer: Lexicon usb 2-1: SerialNumber: Lex1.00 usb 2-1: configuration #1 chosen from 1 choice ALSA sound/usb/usbaudio.c:1263: 3:1:1: cannot get freq at ep 0x1 ALSA sound/usb/usbaudio.c:1263: 3:1:2: cannot get freq at ep 0x1 ALSA sound/usb/usbaudio.c:1263: 3:2:1: cannot get freq at ep 0x83 ALSA sound/usb/usbaudio.c:1263: 3:2:2: cannot get freq at ep 0x83 ALSA sound/usb/usbaudio.c:1263: 3:4:1: cannot get freq at ep 0x2 ALSA sound/usb/usbaudio.c:1263: 3:4:2: cannot get freq at ep 0x2 ALSA sound/usb/usbaudio.c:1263: 3:5:1: cannot get freq at ep 0x85 ALSA sound/usb/usbaudio.c:1263: 3:5:2: cannot get freq at ep 0x85 ALSA sound/usb/usbaudio.c:1263: 3:9:1: cannot get freq at ep 0x1 ALSA sound/usb/usbaudio.c:1263: 3:9:2: cannot get freq at ep 0x1 ALSA sound/usb/usbaudio.c:1263: 3:10:1: cannot get freq at ep 0x83 ALSA sound/usb/usbaudio.c:1263: 3:10:2: cannot get freq at ep 0x83 susanne@linux-s:~> -------------------------------------------------------------------------------------------- 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 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. What my question is to the list: is there any experience yet with a firewire device like Edirol FA-66 and Freebob in terms of stability? Could I have a chance to come to a better and more stable performance by using Firewire rather than USB? best regards and thanks for any hints, Susanne