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Re: odd sound quality from TDT System 3?
- To: AUDITORY@xxxxxxxxxxxxxxx
- Subject: Re: odd sound quality from TDT System 3?
- From: Daniel Oberfeld <oberfeld@xxxxxxxxxxxx>
- Date: Mon, 30 Jan 2006 09:54:20 +0100
- Delivery-date: Thu Feb 2 23:02:19 2006
- In-reply-to: <AUDITORY%200601290000349830.7735@LISTS.MCGILL.CA>
- References: <AUDITORY%200601290000349830.7735@LISTS.MCGILL.CA>
- Reply-to: Daniel Oberfeld <oberfeld@xxxxxxxxxxxx>
- Sender: AUDITORY Research in Auditory Perception <AUDITORY@xxxxxxxxxxxxxxx>
- User-agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.5) Gecko/20041217
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
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
Dr. Daniel Oberfeld-Twistel
Institute of Psychology
Phone ++49 (0) 6131 39 22423
Fax ++49 (0) 6131 39 22480