In the msgs I posted on the wave editing concepts, the numbers I
mentioned aren't displayed anywhere in the wave editor program.
They exist, as Gianni pointed out, in the file, once the wave is
stored, and in the computer's memory when the wave is being
played or edited. These numbers are the essence of what a
digital "sound" really is.
Building the graphical representation of an audio wave is just a
handy way of getting the wave editor program to figure out the
numbers for you, so you don't have to type numbers into some
program. In principle, you could use any source of numerical
data as an audio wave, provided that the numbers don't go out of
range (signed 16-bit integers, if you're making a CD-audio type
of file). In fact, some computer music folks (like me) get
"audio waves" from all kinds of unlikely sources, some of which
are definitely not related to audio at all!
The 16-bit pulse-code modulation (PCM) file format (.WAV) is a
standard way of storing the digital (numerical) representation
of a varying electrical signal. But all approaches to digitizing
or storing signals on a computer involve some kind of conversion
from varying analog voltages to numbers. Another common approach
is "delta-modulation," which stores a '1' if the next sample is
higher, and a '0' if the next sample is lower. When the voltage
remains constant, a string of alternating '1,0' is output.
You can find some good overview material on all this at:
http://en.wikipedia.org/wiki/Digital_audio
Allen
Allen Cobb
http://acobb.com
http://shakespeare.acobb.com
http://timbreproductions.com
-----Original Message-----
From:
Behalf Of Lou Judson
Sent: Thursday, October 20, 2005 9:19 AM
To:
Subject: Re: [Nature Recordists] MT2496 digital input
Oh. I'm just a simple audio engineer and have not used such
tools. I
suppose SoundHack would do it?
Thanks for the info.
Lou Judson =95 Intuitive Audio
415-883-2689
On Oct 20, 2005, at 6:57 AM, Gianni Pavan wrote:
> You can read them by using a hex editor, by
> reading the file into matlab, or by reading the
> file with a simple program that can be written in
> almost any programming language.
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