[ardour-users] Latency Trouble

philicorda philicorda at ntlworld.com
Wed Apr 7 13:57:10 PDT 2004

Christopher K. George wrote:

>I am running Ardour 0.11.2 on latest testing version of Debian using a low-
>latency patched kernel from Agnula.  I compiled the latest versions of ALSA 
>and JACK myself.  I am running an Athlon 2600 with 500MB of RAM.  I have a 
>separate HD for recording audio that supports sustained data rates of 60MB/S 
>according to hdparm -Tt.  I am using an RME HDSP Multiface.  I have assigned 
>it IRQ 9 which is not shared with any other device.  I have 
>set /proc/sys/kernel/lowlatency to 1.  I have disabled all services that I do 
>not need.  My week point may be running the latest testing version of X and 
>I recently had to change mother boards.  The old one had some issues plus I 
>couldn't assign PCI IRQs.  On the old system I had to use a frame size of 
>8192 in order to avoid xruns.  With this setting I was able to record eight 
>tracks indefinetly.  On the new MB I am able to function with a frame size of 
>512.  From the testing I have done so far, the system runs fine with that 
>setting.  I am starting jack as root with:
>jackd -R -d alsa -r 96000 -p 512.
>I can record all eight tracks with a frame size of 128 for a while, but then 
>an xrun will happen.
>Any suggestions?  I am getting along alright using hardware monitoring but 
>would love to have some better latency.
>ardour-users-ardour.org mailing list
>ardour-users at lists.ardour.org
512 frames at 96k=5.3ms latency
128 frames at 96k=1.3ms latency

1.3ms is kinda pushing it. :) You could try xfce4 as a desktop, it's 
quite lightweight compared to KDE. It also has a lot of features that 
are lacking in a very minimal desktop like fluxbox/blackbox.

I suggest you try 256 frames as well, that should be low enough (2.6ms 
or so latency at 96k) for monitoring.

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