[PlanetCCRMA] xruns

Jan Depner eviltwin69@cableone.net
Fri Nov 3 05:39:02 2006

On Fri, 2006-11-03 at 10:01 +0200, DA. Forsyth wrote:
> Hiya all
> Last Friday I recorded a live show, now trying to mix down the 8 tracks 
> into some sort of product (-:
> However, I'm noticing two things...
> firstly, from messages on this list I gather I should not be seeing xruns, 
> but I am seeing quite a lot of them during playback, even without any 
> plugins loaded, ie just raw audio playing back.  I'll append a bit of the 
> jack log at the end of this....   I often hear audible glitches in the 
> playback, esp if I click on stuff other than Ardour, like bring up the 
> qjackctl message log can make it do it every time.
> secondly, on one of the test tracks, I heard a click in the bass track (DI 
> box from amp direct out) and when zoomed in one can see that the wave form 
> has a 'break', ie a sharp transition from one shape to another, as though 
> some samples were missed.   I didn't (happy happy) hear any such clicks in 
> the main recorded tracks, but I am very concerned that there is something 
> I have set up incorrectly.
> The machine is a Gigabyte m/b with Intel 945 chipset, Pentium 4 3GHz (not 
> dual core), 512 megs of 533 ram, it is DDR2 but since there is only one 
> stick it is not running in dual channel mode.  HDD is SATA 80GB Seagate, 
> only one drive.  onboard audio is disabled in CMOS.  17" monitor at 
> 1024x768 off the motherboards VGA port.
> Fedora Core 5 with updates from CCMRA, no fancy anything at all (I don't 
> know how to do anything fancy, yet :-)   I am running the rdt kernel with 
> smp (correct for a P4 with hyperthreading enabled, no?).  I tried the 
> nonSMP kernel last night but it was no worse nor better.
> This glitching is really worrying me, since I think it will get worse if I 
> insert Jamin for the mastering.   problem....!

    I'm assuming that you've made the mistake of setting your
frames/period to something way low like 64 or 128.  For mixdown and/or
mastering you should set it to as high a value as possible.  If you have
hardware monitoring (like with most of the ice1712 chipsets - M-Audio
Delta 1010 for example) you should always set it to as high a value as
possible.  I use 2048.  This should get rid of your xrun problem.

Jan 'Evil Twin' Depner

"Life should NOT be a journey to the grave with the intention of 
arriving safely in an attractive and well preserved body, but rather to 
skid in sideways, chardonnay in one hand, chocolate in the other, body 
thoroughly used up, totally worn out, and screaming 'WOO HOO, what a ride'"