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Re: Input Device

On 14 Jun 01, at 2:51, Tom Brennan wrote:

> Of course, the problem with using a sound card for auditory output is that it is
> not calibrated and even if it was there would be no way to calibrate individual
> speakers other than manually and no way to test for pure tones and output
> linearity.

Of course, *any* system needs to be calibrated.  You would certainly want to
calibrate any speaker or headphone used for research purposes, whether
"manually" or with some automated system.  In this respect a sound card
fares no worse than an expensive lab-grade acquisition system.  As for pure
tones and output linearity, my Daqarta software does real-time spectral
analysis, so it's pretty easy to check these.

And unlike many lab-type boards, a Sound Blaster has a built-in attenuator.
In fact, it is better than many older lab-type manual attenuators as far as
accuracy goes, since it doesn't suffer from leakage/ground-loop problems that
often arise with rack-mounted units.  The steps are very accurate... it's only
Windows that keeps you from knowing about that!

By the way, the next version of Daqarta (v2.10, out in late July) will include
enhanced facilities for automatic calibration, including in-ear calibrations and
probe tube transfer functions.  It's also specifically designed to make it
simple to do a transfer calibration from a reference mic to a "working" mic.

Robert Masta

         D A Q A R T A
Data AcQuisition And Real-Time Analysis
 Shareware from Interstellar Research