[PlanetCCRMA] ardour crackle on writes to firewire drive

John Yates jyates@hvc.rr.com
Wed May 12 17:21:01 2004

Actually it appears that Steve had the right hunch. Reversing the
plug in th AC socket on the drive's power supply has corrected the
problem. The RME Digiface/Cardbus is also powered and of course
neither power supply has a ground pin or a polarized plug to keep
things straight.

I am curious to run the latency test program that you mentioned. It
looks very useful for performance tuning.

Thanks for the tips!

On Wed, May 12, 2004 at 09:16:01AM -0700, Mark Knecht wrote:
> John Yates wrote:
> >Hi all,
> >
> >Trying to get a stable Ardour setup on an HP ZD7001US notebook. All
> >is well when recording to the internal drive, however when recording
> >to an external firewire drive I'm getting a crackle in the audio
> >when the drive performs the writes. It looks like a short burst of
> >moderately low level single sample 'ticks' when zooming in on the
> >recorded track. Anyone have any suggestions?
> >
> >I'm using a Planet install on FC1.
> >2.4.26-1.ll.rhfc1.ccrma kernel.
> >ardour-0.9beta11.2-1.rhfc1.ccrma
> >jack-audio-connection-kit-0.98.0-2.rhfc1.ccrma
> >RME Digiface/Cardbus
> >Maxtor OneTouch firewire drive
> >
> >Hoping to get more performance from the firewire drive than the
> >internal drive.
> >
> >John
> >
> John,
>    You might consider running Benno's latency test program on the drive 
> and look at where you need to set Jack latency with this drive.
>    Linux1394 has notoriously low performance compared to other OS's. 
> Some drives work pretty well, others not so well. Best to test your 
> system for what it can really do.
>    Also, I use Firewire drives exclusivey under windows for audio 
> recording. Look at setting the block (cluster? I'm sleepy) sizes at 
> maybe 32K/block instead the more standard 4K/block. this result in lower 
> CPU overhead to read or record a track and less fragmentation over time.
> Good luck,
> Mark