Subject: Re: Simultaneous play record in Matlab on mac From: Bob Masta <audio@xxxxxxxx> Date: Sat, 26 Nov 2011 08:30:52 -0500 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>This is not an answer to your question, but just a tip: If you need to measure latency of any sort, note that in general you can't rely on any particular synchrony or known latency between the stimulus going to the sound card outputs, and the response from the card inputs. The way around this (for mono experiments anyway) is to monitor the output signal with one of the input channels, and use the other input channel for the response. Inputs have perfect synchrony with each other, so you can measure the latency between the stimulus and response on their respective input channels. If your stimulus has a very sharp rising edge that causes it to leak into the response chanel when wired this way, and you can't ameliorate it by re-routing and careful wiring, there is a sneaky work-around for this as well. Since both output channels have perfect synchrony with each other (just not with the input channels) you can generate a dummy stimulus on one output that is in exact synchrony with the real stimulus on the other, but which has a slower rise time. As long as you can still find a reliable reference point anywhere on the dummy, you can deduce where the onset of the true stimulus is relative to this point, and correct the input-derived stimulus onset accordingly. Best regards, Bob Masta ----------------------------- On 25 Nov 2011 at 15:52, Stephanie Bertet wrote: > Hi all, > > I am trying to do some impulse response measurements using Matlab on Mac. > Is there a nice way to play and record simultaneously as it is done on Windows with Data acquisition toolbox or pa_wavplayrecord? > Apparently it can be done with Psychtoolbox but does not work on 64 bits, and I am running out of ideas where to look.. Please, help! > > Thanks, > Stephanie > > ----------------------- > Dr. Stéphanie Bertet > Sonic Arts Research Centre > Queen's University Belfast > http://www.sarc.qub.ac.uk > > Bob Masta D A Q A R T A Data AcQuisition And Real-Time Analysis www.daqarta.com Scope, Spectrum, Spectrogram, Signal Generator Science with your sound card!