Altair32 Emulator "Easter Egg" idea

Jim Battle frustum at
Fri Mar 4 17:57:52 CST 2005

Vintage Computer Festival wrote:

> On Fri, 4 Mar 2005, Jim Battle wrote:
>>One other thing I have done is to emulate the music card -- just a
>>single pole RC lowpass filter hooked up to the S-100 INT* line.  The
>>"MUSIC" program would take a score and compile it into a program to
>>toggle the INT line to produce polyphonic music -- although the notes
>>aren't very well tempered as they get higher in frequency.  It is pretty
>>impressive that it works as well as it does:
> Very cool!  Did you record this from the emulator or from an actual
> Sol-20?  It sounds as good as what the Apple ][ could produce, which I
> suppose makes sense since it's generating sound using the same principal.
> How do I load and play the sound files?

The web site has the MUSIC program that you can load into memory, and a 
number of scores that can either be loaded directly into memory or which 
can be "sourced" into the keyboard as if you had typed them (the 
cassette emulation would work too, but I didn't bother putting all of 
this on virtual cassettes because it is as painful to use as a real 

Once you load a score, you have to compile it (IIRC just type 
"S<return>"), then you can play it ("P<return>").  In the emulator 
control panel turn on sound; there are also three sliders for setting 
the volume of for the INT RC filter, for the fan noise, and disk noise. 
  There is also a button for dumping the output to a .WAV file.  One 
more thing to watch out for is that the program uses the 8b DIP switch 
settings to control the tempo; flip them all from what the emulator 
defaults them to (all on instead of all off, I think).

I don't have a "sound card", although it would be trivial to make one. 
The sample is just captured from the emulator.

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