[ardour-users] auditioning groups of tracks at once & disk too slow

Kevin Cosgrove kevinc at doink.com
Fri Jan 13 22:49:26 PST 2006

> > > Is there some way to assign a mix of one take to a bus or
> > > something, and then [un]mute the bus when I want to play with
> > > auditioning?
> >
> > Mixgroups. I'd put the relevant takes on extra tracks, set     
> > up mixgroups like "take 1", "take 2" etc, assign and then      
> > exclusive-solo the mixgroups with ctrl-alt-click. This gives   
> > you ABC with one click.                                        

OK, I did that, take 1 through take 8.  At one point in the exercise 
ardour told me to save, quit, then restart jack with more ports as 
I'd run out.

I might have overdone it on the number of tracks I've got, just over 
70.  The reason I say this is that I'm getting a message I've never 
seen from ardour before:

	The disk system on your computer
	was not able to keep up with Ardour.

	Specifically, it failed to read data from disk
	quickly enough to keep up with playback.

I've been doing just fine up until now with 10-20 tracks.  Is ardour 
reading all of my tracks, even though most of them are muted?  I 
would imagine that it would have to in the event that I wanted to 
unmute a track quite a ways into playback.  I think the alternative 
would be to mess up playback when the tracks were unmuted.

I haven't seen any xruns.

My jack command, run via qjackctl, is:

	/usr/bin/jackd -R -p512 -dalsa -dhw:1 -r44100 -p1024 -n2

I'm not sure if adding extra unused jack ports increases its drag
on system resources or not.  Anyone know?

My system is 2GHz Celeron, 1GB RAM, 200GB Seagate Barracuda
ATA.  It's running a 2.6.7 "-mm" kernel with ALSA 1.0.6a.  My
filesystem is ext3.  I haven't done any tuning with tune2fs nor
hdparm.  I'm not using anything special for tmpfs, i.e. I didn't
force it to be in RAM.  The sound "card" is an M-Audio Delta
1010.  I'm running KDE, 1 xterm qjackctl, jackit 0.99, and ardour
0.99.  My load average runs between 11% and 18% during playback.

'hdparm -tT /dev/hda' says:

     Timing buffer-cache reads:   1260 MB in  2.01 seconds = 628.21 MB/sec
     Timing buffered disk reads:  168 MB in  3.01 seconds =  55.82 MB/sec

Is there anything I could or should do to improve performance in this 
regard?  Should I just use fewer tracks?

> Mixgroups, hmmm.  I didn't know about locking the sliders, nor
> ctrl-alt-click until your mentioning them.  I just reread the
> mixer section of the manual and checked mixgroups make more sense
> now that I have a use for it.  I'll try this tonight.  Thanks for
> the tip.

Well, I'm not exactly sure what "exclusive-solo" is, but with the 
mixgroup checked, then the "mute" for any channel in the group will 
act on all the other channels in the mixgroup, letting me hear only 
what I want.

Thanks all....

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