Re: [LAU] (Ardour) How to get rid of delay when recording ?

On Sat, 13 Feb 2016, jonetsu(a)teksavvy.com wrote: sudo apt-get install linux-lowlatency for a start. (I would imagine you have linux-generic right now) also install rtirq. As you are running a delta1010 (I think), sudo edit /etc/default/rtirq... the line that says: RTIRQ_NAME_LIST="something something" to: RTIRQ_NAME_LIST="snd_ice1712" Never run jackd as root. (you may not be able to run as a user after wards which, as someone else already said, you have to do in order to use it) speaking of jackd... if you used Software Centre to install it... sudo mv /etc/security/limits.d/audio.conf.disabled /etc/security/limits.d/audio.conf and probably add yourself to the audio group before loggin out and back in. (Software center does not install jackd correctly) If you have more than one PCI slot, and cat /proc/interrupts shows snd_ice1712 sharing an interrupt with something else you might try moving it to another slot (sharing with fasteoi* is ok it seems). people say it is worth while building a true realtime kernel by patching the mainline and rebuilding, but I have not done that, I do turn cron off while recording though as that seems to help... with a RT kernel that shouldn't be needed. Do change your CPU governor from OnDemand to Performance. Even running the cpu at the lowest speed possible (800Mhz normally) seems to work better than the faster OnDemand. So if you have trouble with heat (you shouldn't as you should not be doing 100% cpu load while doing audio) it is better to set the CPU governor to UserSpace and set the speed to a steady lower speed where temperature is ok. Do find out how to change "swappiness" to 10 rather than 60 so the kernel doesn't start preemptive swapping even though it is using less than half your RAM :P If you want to run Jack really low (16/2 or 32/2) it may be worthwhile turning hyperthreading off. I have found a difference at those latencies, but not at 64/2 which is normally good enough. That is the short list, I may have missed something. Finally, the ice1712 based AIs like you have are able to do 1-2ms monitoring. If you are hearing delay, you are not using HW monitoring. Some of the input signal is going through your recording chain as well. Or to put it another way you are not _just_ using HW monitoring. I have made this mistake often enough to know :) -- Len Ovens www.ovenwerks.net