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From: phil@anduin.cs.liverpool.ac.uk (Phil Jimmieson)
Newsgroups: comp.sys.mac.misc,comp.sys.mac.programmer
Subject: Re: MacRecorder sampling rate
Message-ID: <1990Oct15.121353.1917@anduin.cs.liverpool.ac.uk>
Date: 15 Oct 90 11:13:53 GMT
References: <2112@anaxagoras.ils.nwu.edu>
Organization: Computer Science, Liverpool University
Lines: 50

In article <2112@anaxagoras.ils.nwu.edu>, sandell@ils.nwu.edu (Greg Sandell) writes:
> I frequently download MacRecorder files from other places, and
> the sampling rate is set wrong.  For example, the srate should
> be 11000, but the MacRecorder file thinks it's 22000.  I can find
> no way to set the playback sampling rate while running MacRecorder.

While you're playing the sample in SoundEdit you can use the "Set Pitch"
command - and set the playback pitch.  The problem with doing this is that if
you want to put the sound into a program or somesuch the speed is still wrong -
and the only way I know how to fix this is by using Resedit to change the
sampling rate signature bytes.

> 
> Does anybody know how to change the playback sampling rate by
> playing with the resource fork, or any other way??
> 

OK, using ResEdit (on a copy of your sample of course :-)  ) open up the sample
and look for the following signature:

56EE 8BA3  - this is a 22KHz sample

or

2B77 45D1 - this is an 11 KHz sample

now just modify the string of bytes to the appropriate speed (i.e. change your
22KHz signature to the 11KHz one and your sound will be played at half the
speed, and vice versa.)  I have done this to a few samples.  I've never needed
to change any samples to 7.5 or 5Khz - so I don't know what the respective
signatures are - you could try saving 4 different speed versions of the same
sample - and comparing the header - which contains the speed signature to find
out what they are for the two lower quality sampling rates.

Hope this is the info you wanted - modify sound resources at your own risk of
course... :-)

> Thanks,
> Greg
> ****************************************************************
> * Greg Sandell (sandell@ils.nwu.edu)              Evanston, IL *
> * Institute for the Learning Sciences, Northwestern University *
> ****************************************************************

Phil Jimmieson,           ***************************************************
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