Re: odd sound quality from TDT System 3?

[Daniel Oberfeld <oberfeld@xxxxxxxxxxxx>]

Dear list,

we bought some TDT Sytem 3 modules two years ago (two PA5 and one HB7), 
using exactly the configuration Volker Hohmann recommended - and in fact 
it was him who pointed me to the excellent 8 channel AD/DA converter RME 
ADI/S - thanks Volker!

Now, when I setup the system back then, I always had a clearly audible 
noise/buzz on one channel. I exchanged *many* emails with the TDT 
support team, but we didn't find the reason for the noise. Finally, I 
removed all modules from their rack and then put them back in - and the 
noise was gone! So it seems that for one of our modules, the PCB 
connectors TDT use inside their racks had some contact problems, 
resulting in some high-frequency noise pickup.

For those who want to use Matlab plus AD/DA plus analog signal conditioning:

As for my experiments I need at least two audio channels for stimulus 
generation *plus* two channels for the generation of visual signals 
(LEDs marking observation intervals etc.) I spent quite some time 
looking for a tool capable of multi-channel playback from Matlab and 
finally found pa_wavplay

(http://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=4017&objectType=file)

which is a Portaudio-based tool that can playback and record on as many 
channels (simultaneously) as the sound card supports - via an ASIO, MME 
or WDM driver. Works very stable, although you cannot control the 
latency between input and output and you cannot use disk streaming. So 
if anyone knows a tool which also includes the latter two features, 
please let me know!

All the best

Daniel

---------------------------
Dr. Daniel Oberfeld-Twistel
Universität Mainz
Institute of Psychology
Experimental Psychology

Staudingerweg 9
55128 Mainz
Germany

Phone ++49 (0) 6131 39 22423
Fax   ++49 (0) 6131 39 22480
http://www.staff.uni-mainz.de/oberfeld/