[PD] Best PD+OS/Hardware combinations for low audio latency?

[Roman Haefeli]

On Sun, 2008-03-30 at 12:30 -0700, Joe Newlin wrote:
> I want desperately to be able to process guitar in "real time" with PD.

cool! 

> I have a Sony VAIO laptop and Edirol FA-66 Firewire soundcard.
> 
> It seems that using Windows is not an option, since I get outrageously
> high audio latency with PD, and a search through the mail list
> archives suggests that the consensus is that this is unavoidable in
> Windows.

definitely not true. it certainly depends on what you consider high
latency. on windows with pd running on my built-in audio card, i could
use a buffersize of 14ms (in the pd media dialog, didn't measure the
actual round-trip). this might be too much for real-time processing a
live signal. however, with the hdsp rpm soundcard i could go down to 3ms
(still on windows). 
on linux (with old ubuntu dapper) i can go a bit lower with both cards.
(128samples buffer for jack, when running on the hdsp without x-runs)
without really knowing, i am tempted to say, that good hardware and
well-written drivers are more latency critical than the os. on windows i
had good experience with hdsp and motu cards.

> I'm trying to get the FA-66 working with Ubuntu, but I'm not quite
> smart enough to understand how to do this.

not that i am an expert, but from what i heard, firewire audio seems to
be harder to set up. don't know about the fa-66 in particular, but with
a decent linux os (ubuntu gutsy) and no fear to compile the necessary
driver yourself (freebob or.. what's its successor called again..?),
quite a lot of the fw cards are supported nowadays (i heard that someone
got a motu 824 card running).

> What I'm wondering is:
> 
> 1. What OS/hardware combinations have you found to result in low audio
> latency with PD?

ubuntu gutsy has a linux-rt package in its distro. setting up a system
optimized for audio should be quite easy on gutsy (at least from my
experience). check, if the new ffado driver (i think that's how it's
called) supports your card. 
regarding decent audio hardware, i am pretty much in favor of the hdsp
series. those are also pretty well supported under linux. 

> 2. Isit possible to accomplish this with Ubuntu and the FA-66, or
> should I give up and try something else?

i just checked the ffado supported harware page and your card is listed:
http://www.ffado.org/?q=devicesupport/list


> 3. If it is possible with Ubuntu, are there other resources for
> figuring this out, other than stumbling through web forums that assume
> I understand more than I do?

i never tried installing a ffado driver myself. personally, i would try
to compile it myself. but probably you find an external repository for
gutsy, that provides those drives as a package.

hope this helps.

roman


	
		
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