[stella] Sound experimentation

Subject: [stella] Sound experimentation
From: Nick S Bensema <nickb@xxxxxxxxxxxx>
Date: Tue, 15 Apr 1997 09:15:53 -0700 (MST)
Last weekend I did a bit of experimenting and god my 2600 to play a little
tune.  I just threw it together, using no vertical sync.  I just set
T1024T to some enormous amount , played the note, waited for T1024T to
time out and then decreased the volume for another huge number of cycles.
Register output to the frequency and control channels are sent to the
playfield registers for debugging purposes.

It's in a very low key, and there are no drums, and I only put in one
bar of it.

As I was coding it, I realized the kind of table that would be needed
in order to better automate the process of sequencing.  This table could
have names and cents-off values for humans to interpret, but alongside that
a cents-from-C1 value.  A half-step is 100 cents, of course.... so
supposing I wanted the following melody where the interval from root is
as follows: 1 5 1 3 5 b7 5 6 5 1 5... et cetera.  A program could go through
just about every key it can find to represent the root (1), and of course
find as close a match as it can for that root plus 700 cents for the fifth,
root plus 400 cents for the third, etc.  It would try as many keys as it
could and print out the register values for the n best keys.  

I'm going to have to find a text editor that can cut and paste in
rectangles so that I can get a columnar list that an awk script or
C program could easily parse.  Pure cent values would have to be
manually calculated, but there is a definite pattern to the 
progresison of intervals down the list.  Perhaps my program would
only need a list of the value of 0 for each distortion, and 
extrapolate the rest from this pattern.

Then all I'd have to do is write the program, with provisions to exclude 
certain distortions if desired, and perhaps even to output in an assembler-
readable format.

I'll send the "song" up to the list when I can.  I'm at school right
now.


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