Thank you Ray :) seemingly it's solved. I can't test it now, but the bad messages are gone away [1]. What was the culprit? Regards, Ralf [1] [root@archlinux src]# pacman -Syu jack2 [root@archlinux src]# pacman -Qi jack2 Packager : Rashif Rahman Architecture : x86_64 Build Date : Sun Sep 16 16:17:03 2012 Install Date : Sun Sep 16 18:49:50 2012 ###################################################################### [spinymouse@archlinux ~]$ jackd -dalsa -dhw:0 -r44100 -p128 -n2 jackdmp 1.9.8 Copyright 2001-2005 Paul Davis and others. Copyright 2004-2011 Grame. jackdmp comes with ABSOLUTELY NO WARRANTY This is free software, and you are welcome to redistribute it under certain conditions; see the file COPYING for details no message buffer overruns no message buffer overruns no message buffer overruns JACK server starting in realtime mode with priority 10 control device hw:0 control device hw:0 audio_reservation_init Acquire audio card Audio0 creating alsa driver ... hw:0|hw:0|128|2|44100|0|0|nomon|swmeter|-|32bit control device hw:0 configuring for 44100Hz, period = 128 frames (2.9 ms), buffer = 2 periods ALSA: final selected sample format for capture: 32bit integer little-endian ALSA: use 128 periods for capture ALSA: final selected sample format for playback: 32bit integer little-endian ALSA: use 128 periods for playback [spinymouse@archlinux ~]$ uname -a Linux archlinux 3.5.3-1-ARCH #1 SMP PREEMPT Sun Aug 26 09:14:51 CEST 2012 x86_64 GNU/Linux ###################################################################### [spinymouse@archlinux ~]$ jackd -dalsa -dhw:0 -r44100 -p128 -n2 jackdmp 1.9.8 Copyright 2001-2005 Paul Davis and others. Copyright 2004-2011 Grame. jackdmp comes with ABSOLUTELY NO WARRANTY This is free software, and you are welcome to redistribute it under certain conditions; see the file COPYING for details no message buffer overruns no message buffer overruns no message buffer overruns JACK server starting in realtime mode with priority 10 control device hw:0 control device hw:0 audio_reservation_init Acquire audio card Audio0 creating alsa driver ... hw:0|hw:0|128|2|44100|0|0|nomon|swmeter|-|32bit control device hw:0 configuring for 44100Hz, period = 128 frames (2.9 ms), buffer = 2 periods ALSA: final selected sample format for capture: 32bit integer little-endian ALSA: use 128 periods for capture ALSA: final selected sample format for playback: 32bit integer little-endian ALSA: use 128 periods for playback [spinymouse@archlinux ~]$ uname -a Linux archlinux 3.4.4-rt14-1-rt #1 SMP PREEMPT RT Fri Jul 20 13:16:40 UTC 2012 x86_64 GNU/Linux