Hmm, I use Debian Testing, with JACK and a USB sound card (for both recording and playback) also using Audacity and jack-record. I don't have Pulseaudio installed at all. And I've never had left-right channels out of sync by even two samples. Don't know what's going on with your setup. Perhaps try booting the machine from an audio-oriented distro like Musix 3, KXStudio, or ArtistX and see if you have same problem? David W. Jones gnome@xxxxxxxxxxxxx authenticity, honesty, community http://dancingtreefrog.comOn Dec 3, 2016 13:59, Paul Davis <paul@xxxxxxxxxxxxxxxxxxxxx> wrote: > > There's more or less no way for JACK to do this. Its entire design is "be woken by hardware to process N samples; process N samples; go to sleep". It is a synchronous low latency design that does not offer scope for processing different channels or different outputs at different times. > > On Sat, Dec 3, 2016 at 7:20 PM, David Klann <dxklann@xxxxxxxxx> wrote: >> >> Greetings, >> >> Long-time Linux user, and relatively new JACK user here. I have built >> some audio workstations for the community radio station where I >> volunteer (WDRT, Viroqua, WI, US). I recently switched one of the >> workstations to use JACK, along with PulseAudio. We use Audacity to edit >> audio and we have noticed that the "left" and "right" channels are out >> of sync with each other. We have witnessed the "skew" to be as few as >> two samples (which is unnoticeable to the ear) to as many as a couple >> hundred samples (which sounds a lot like a phase error). >> >> We performed a lot of troubleshooting, including swapping PCI audio >> cards (ESI Juli@, Digigram VX222), disabling JACK, running Audacity on >> the same hardware booted from a USB stick and a completely different >> Debian environment. I am not *completely* confident, but the likely >> culprit seems to be JACK. >> >> We have recorded audio using jack-record and experienced the same >> left-right channel skew. >> >> Can anyone help point to JACK or OS configuration parameters that we >> might look at to get our left and right channels in sync? >> >> Details: >> >> OS: Debian Jessie (8.6), up to date (kernel: 3.16.0-4-amd64 #1 SMP >> Debian 3.16.36-1+deb8u2 (2016-10-19) x86_64 GNU/Linux) >> JACK (jackd2): 1.9.10+20140719git3eb0ae6a~df >> PulseAudio: 5.0-13 >> ALSA: 1.0.27+1 >> CPU: Intel(R) Core(TM) i5-2400 CPU @ 3.10GHz >> RAM: 8GB >> Audio Cards: ESI Juli@ PCI, Digigram VX222HR PCI >> >> Thanks for your consideration! >> >> ~David Klann >> >> >> _______________________________________________ >> Linux-audio-user mailing list >> Linux-audio-user@xxxxxxxxxxxxxxxxxxxx >> http://lists.linuxaudio.org/listinfo/linux-audio-user >> > _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
