Hi Robin, On 03/08/2012 02:25 PM, Robin Gareus wrote: Neither jack 0.121.2 nor jack 1.9.7 does produce xruns (like those reported by jack when it is not fast enough to handle the sound card data). no audible click, no xrun sometimes one audible click, no xrun (sine test tone on an independent signal graph) btw, the time seems to scale with the fragment size: 1024 samples/fragment: giso@helios:~$ time (for k in system:playback_{1..26}; do jack_connect system:capture_1 "$k"; done) real 0m2.419s user 0m0.029s sys 0m0.811s 4096 samples/fragment: giso@helios:~$ time (for k in system:playback_{1..26}; do jack_connect system:capture_1 "$k"; done) real 0m9.677s user 0m0.017s sys 0m0.823s Glitch-free connections are nice, but jack sessions with several hundred ports/connections make jack2 nearly unusable in terms of connection time :-( It looks as if it would take four cycles to complete a port connection. I think here is some space for improvement (e.g. allow asynchronous connections and return immediately from jack_connect), but maybe this will come with all the session management solutions... (actually both versions have their pros and cons, which is the reason for me to switch often between them, depending on my actual needs). Giso