Subject: Re: Input Device From: Bob Masta <masta(at)UMICH.EDU> Date: Thu, 14 Jun 2001 08:47:21 -0400On 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 tech(at)daqarta.com D A Q A R T A Data AcQuisition And Real-Time Analysis Shareware from Interstellar Research www.daqarta.com