performance in pd - audiobuf, etc

Karl MacMillan karlmac at
Mon Dec 11 20:56:05 CET 2000


Really the only way to fix this problem is to adapt PD to use ASIO
drivers.  This was mentioned recently on the list, but the problem with
the normal windows sound drivers is that they go through a kernel mixer
(called kmixer - this allows more than one app to access a sound card
simultaneously) that adds a minimum of 30ms.  It seems that a lot of pro
cards circumvent this with their ASIO drivers.

The best solution is linux, but then you don't get to use your layla
because the manufacturer is not nice.  Of course, if you are willing to
buy a macintosh you could just be an RME hammerfall card instead, install
linux + low-latency kernel, and enjoy 5ms latency regardless of disk or
cpu load.  As for the Macintosh latency I think that the 6ms measurement
is not a real measure of end to end latency - I have never seen the
Max/MSP machines that I have access to (G3s with MOTU 2408) get anything
near that because of the complete inadequacy of the MacOS in all regards
(sorry about that comment - I couldn't stop myself).


On Mon, 11 Dec 2000, Michael Lechasseur wrote:

> 	Perhaps you could dual boot to Linux?  I don't have any latency data for PD
> on Win2000, but if you'd like to write a latency test patch, I could run it
> on my system and send you the results?
> 	I've wanted to test this since applying the kernel low-latency patch, and
> have never gotten around to it.
> 	I have an Athlon 600, 64MB Ram, Redhat 6.2, Kernel 2.2.16 with the
> low-latency patch.
> > -----Original Message-----
> > From: d d [mailto:denglertdp at]
> > Sent: Monday, December 11, 2000 1:02 PM
> > To: pd-list at
> > Subject: performance in pd - audiobuf, etc
> >
> >
> > Hello, I'm new to PD, and have been using it sporadically for
> > several weeks.
> > It is extremely interesting, seems to do the things I can't do with my
> > NordModular. My thanks to all who made it possible!
> >
> > I know you probably don't want to hear this question again, but I was
> > wondering if there was a way to get real time audio processing
> > performance
> > out of PD. (windows 2000 pent III 500mHz, awe64, echo layla 20bit)
> >
> > I've tried adjusting all the command params, disabling devices, changing
> > audiobuf, etc
> >
> > Is there anyway to knock the latency to hardware like levels on
> > my system?
> > Even if the answer is different hardware, OS, etc
> > I'm considering a Mac purchase because cycling74 claims w/
> > certain hardware
> > a 6ms latency can be had.
> > Is anything this low possible with PD?
> > I'd much rather stay within windows.
> >
> > Sorry for the bother with this question
> >
> > I'd like to have this ultimate control over processing/creating
> > that PD can
> > give, but I also need hardware like latency In/Out
> > I don't want to spend money on a Kyma, because it seems logical that a PC
> > can do this sort of thing these days (what with the nifty fast chips and
> > all)
> >
> > Thanks all who read this far, sorry for the dull question
> > -daniel
> > _________________________________________________________________
> > Get your FREE download of MSN Explorer at
> >

| Karl W. MacMillan                                 |
| Computer Music Department                         |
| Peabody Institute of the Johns Hopkins University |
| karlmac at                           |
|                      |

More information about the Pd-list mailing list