forum support group advice, may it be of use to others suffering in the pitfalls of hard-
and software flaws.
The setting: USB audio card attached to a notebook running Windows (XP SP3, ymmv)
and a fair stack of decent audio software (e.g. Ableton, Jack Audio, Traktor)
The challenge: No cracks / crackles / pops / clicks / static noise during playback
Can't be too hard, can it?
- first of thanks to the people contributing solid facts in several user forums,
all this would not have crystalized into a working setup without
the public chat of kevinshields and Daniel aka Kilgore_Trout over at
http://forums.lenovo.com/t5/T61-and-pri ... m-p/237329
and the comments of timur at
http://www.gearslutz.com/board/music-co ... -irqs.html
- Checking for IRQ-sharing in Windows XP:
- Open the devicemanager and select the "Devices by connection" view to
find out to which of the USB Controllers your soundcard is connected to by clicking
on the + sign next to it. Once you found your USB sound card you know which interrupt
it depends on: It's the interrupt of the USB Controller it is connected to (in my case
it has the ID "27C8"). - Look at the Shared Hardware Resources with the tool msinfo32.exe
or open the devicemanager and select the "Resources by connection" view.
If you use msinfo32.exe (sysinfo) and don't find the USB Controller ID
listed with its IRQ in the shared hardware resources, that might indicate
that the IRQ is actually not shared. Otherwise it might be that the
shared IRQ causes some problems. - In the case of the Thinkpad T60, the two USB ports on the right side of the machine
seem to be related to USB Controller ID "27C8", while the one on the left side is
related to the USB Controller ID "27CA" (check by replugging the USB audio) - In the case of the Thinkpad T60, it seems to be a good idea to disable the
"Intel(R) PRO/1000 PL Network Connection" device, sharing IRQs with the right side
USB ports, you probably use wireless networking anyway. Otherwise it might be a good
idea to try the left USB port for the audio card. - In case of doubt check out all the hardcore advice about APIC vs IRQ-sharing all over
the place, e.g. over in the M-Audio forum for starters. If you are into some
reality check for a change, I recommend the APIC article at MS (google: apic microsoft).
Be sure to check Kilgore_Trouts above mentioned posting for a way out of this c/trap.
- Open the devicemanager and select the "Devices by connection" view to
- Ableton process priority:
- It seems to be a good idea to raise the process priority of Ableton Live (8.2)
to realtime priority. The most convenient way to achieve this is by downloading
and installing the "Prio Saver" tool from http://www.prnwatch.com/download.html .
If you don't like that, you can write a batch file containing a command similar to:
start "runhigh" /b /realtime "C:\Program Files\Ableton\Live 8.2\Program\Live 8.2.exe"
- It seems to be a good idea to raise the process priority of Ableton Live (8.2)
- ASIO and Jack:
- If you think the ASIO driver provided by you audio card manufacturer might be too old
try ASIO4all. - If you like to connect other audio applications to Ableton Live (or to anything else)
download the Windows version of the excellent Jack audio server:
http://www.grame.fr/~letz/jack-1.9.6.tgz - take care to adjust the audio buffer sizes / latency settings in jackd and your ASIO
driver to the same values. In the case of a T60 with the M-Audio FTP driver,
256 and 44.1kHz seems to be a safe setting (48k didn't work for me).
- If you think the ASIO driver provided by you audio card manufacturer might be too old
In the end, assigning realtime priority to Ableton was the silver bullet in my case.
A silver bullet against nightmarish indeterministic behavior of this particular combination
of OS and audio software. Maybe it's a demanding setup, but this is software claims professional
status, doesn't it? It would be much better, if on top of money the customer would not have to
spend a lot of time and energy into getting the most basic things done with this software.
What good is "the bridge" and other fancy addons if people have to face this kind of... mess.
Good luck, and thanks again to the supportive users.