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Re: Sound card problems (UNCLASSIFIED)

Classification:  UNCLASSIFIED 
Caveats: NONE

Hi Rahul,

First of all - USB based sound cards are notoriously terrible for temporal
accuracy. Your best bet really is to get an PCMCIA-based card.
The reason is, the data bus of the USB is not all that fast - it's high
bandwidth, but has a slow sample rate - default is only 125 Hz.
This means you can only "deliver" a sound to begin roughly every 7.5 ms...
So if the sound delivery from the hsystem does not line up appropriately,
you will have a gap while it "waits" to sync w/ the USB data bus. 

Now there is hope!
In Windows, you CAN change the USB sample rate, using an applet.
This one here will do it:

It allows changing the data rate up to 1000 Hz (1 ms resolution).

Note - this changes the access rate for ALL USB devices; mice, remote
drives, access keys, etc. It may also decrease the time you get out of the
battery, due to larger power consumption.

IMO, spend the $$ on a good PCMCIA card and be done with it.

Good luck,

Dr. W. David Hairston
Research Fellow
Oak Ridge Affiliated Universities

Auditory Research Team, VAP, HRED
Army Research Lab
Aberdeen Proving Ground, MD 21005

Office: (410) 278-5925
Fax:    (410) 278-3587

-----Original Message-----
From: AUDITORY - Research in Auditory Perception
[mailto:AUDITORY@xxxxxxxxxxxxxxx] On Behalf Of Shrivastav,Rahul
Sent: Friday, August 08, 2008 2:22 PM
To: AUDITORY@xxxxxxxxxxxxxxx
Subject: [AUDITORY] Sound card problems

Folks - I wonder if someone on this list can help us with a problem we are
having with our sound card:


We purchased a Creative E-MU 0202 USB sound card to use with a laptop.
Unfortunately, when we play wav files through this sound card, they
occasionally skip for a few milliseconds. The skipping occurs at random
intervals and does not seem related to the file size. The problem does not
occur if we play the same sound file through the internal soundcard on the
same laptop. We have already done most of the usual troubleshooting steps -
update/reinstall drivers, used both USB 1 and USB 2 ports, etc. -  but none
seem to have worked.


Has anyone observed such a problem before? Any solutions that you can


Also, do you have another "favorite" amongst external sound cards? We want
to use it to run some speech tests in the field. 


Thanks for all your help!






Rahul Shrivastav, Ph.D.

Associate Professor

Dept. of Communication Sciences and Disorders

Dauer Hall, PO Box 117420

University of Florida

Gainesville, FL 32611


Phone: ++-1-(352)-392-2113 (ext. 230)

Fax: ++-1-(352)-846-0243



Classification:  UNCLASSIFIED 
Caveats: NONE

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