External sound devices for laptops (Andrew Faulkner )

Subject: External sound devices for laptops
From:    Andrew Faulkner  <andyf(at)PHONETICS.UCL.AC.UK>
Date:    Wed, 10 Jul 2002 17:32:08 +0100

<html> Stuart Rosen and othere here have been using a Dell laptop for masking experiments, <br> but he is not&nbsp; completely happy with the sound quality (occasional glitches; a bit too much <br> noise in the background -- in particular a 200 Hz periodic complex), so is<br> looking into an external box. The SoundBlaster Extigy looks good (96 kHz <br> sampling rate, 24 bits) -- but does anyone have any experience with this or <br> similar external sound boxes? I guess it should plug in to a USB port to be <br> readily used, as does the Extigy. I'd also like to have ready access to its <br> workings from Windows 2000 and Matlab, perhaps through an ActiveX <br> controller. At about 149 dollars or pounds, this seems very good value to <br> me.<br><br> Thank you all in advance --<br> P.S. If anyone is interested in running psychacoustic tasks through Matlab, <br> I am having reasonable success using an ActiveX sound card controller that <br> Rhodri Cusack developed to control Windows sound cards (thank you, thank you <br> Rhodri! And to Bob Carlyon who let me know about it).<br> <font color="#0000FF"><u><a href="http://www.mrc-cbu.cam.ac.uk/personal/rhodri.cusack/vb/download.htm" eudora="autourl">http://www.mrc-cbu.cam.ac.uk/personal/rhodri.cusack/vb/download.htm<br> </a></u></font>I only manipulate the master volume control (keeping the digital signal as <br> close to maximum as possible) as the background noise level from the laptop <br> is determined by its setting -- the lower the better. The wave volume <br> control has no effect on this background noise. You need to measure the <br> behaviour of your volume control but the attenuations on my laptop were in <br> 1.5 dB steps for small attenuations (up to 19.5 dB) and in 3 dB steps after <br> that to about 42.5 dB.<br> I also have been using a Logitech serial 3-button mouse to get responses, as <br> Matlab has good access to serial devices implemented explicitly. (Dontcha <br> just hate having to select a box on the screen, as well as pressing a <br> button!) A student of mine has also cannibalised one of these to make a more <br> typical response pad simply by soldering other buttons in parallel to the <br> switches in the mouse. You need to be a little careful about what you look <br> for on the serial port as different serial mice send different numbers of <br> bytes, but it is a relatively simple matter to make it work right. I <br> currently have this set up working during PET, with the listener flat on his <br> back and resting his hand on an inclined response box with two buttons.<br><br> <x-sigsep><p></x-sigsep> Dr Andrew Faulkner<br> Principal Research Fellow<br> Dept Phonetics and Linguistics<br> UCL (University College London)<br> Wolfson House<br> 4 Stephenson Way<br> LONDON NW1 2HE<br> tel 44 (0)20 7679 7408 (direct)<br> fax 44 (0)20 7383 0752<br> e-mail andyf(at)phon.ucl.ac.uk<br> WWW: <a href="http://www.phon.ucl.ac.uk/home/andyf/" eudora="autourl">http://www.phon.ucl.ac.uk/home/andyf/<br> </a></html>

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