Date: Mon, 22 Dec 1997 11:19:22 +0000 (GMT) From: Stephen Roome <steve@visint.co.uk> To: multimedia@freebsd.org Subject: precise soundcard tuning ? Message-ID: <Pine.BSF.3.96.971222110348.5515A-100000@dylan.visint.co.uk>
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I wrote a really simple program last night that just writes an X Hz sin wave to a file as raw 16 bit unsigned data. I then used sox to convert this to a WAV file and played it with rplay. Although my program seems to work fine, 440Hz from it just doesn't match the A/440 tuning fork I've got. The computer is about a semitone flat, unfortunately I need it to be perfect (or very close anyway ?). I figured it was possible that I was screwing up in some conversion somewhere, but PI looks right and writing a 2 second file with a sample rate of 44100Hz comes out as 88200 long, which seems correct to me. So, is there something obvious I've missed or is there a problem with the sound driver or with my soundcard that is making my machine play sounds slow ? I'm using a Creative Labs AWE64, and the stock sound driver from current as of December 12, sox12.12 and rplay 3.2.0b6 installed as packages. Any helpful pointers? [If using the pc speaker is going to get me a more accurate pitch then I'll try that, that's all I need] Steve. -- Steve Roome - Vision Interactive Ltd. Tel:+44(0)117 9730597 Home:+44(0)976 241342 WWW: http://dylan.visint.co.uk/
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