Release of DMS Drummer: A Percussion Sequencer for the Apple II

["Michael J. Mahon" <mjmahon@aol.com>]

With inspiration and musical mentoring provided by Seth Sternberger
of _8-Bit Weapon_, I've impemented a percussion sequencer/synthesizer
for the Apple II.

It allows a user to create sequences as long as 255 patterns, where
each pattern is one of a set of 16 musical measures. Within each of
these patterns, any one of 8 percussive voices can be played at any
1/16th note boundary.  In addition, the "pitch" for playing back the
percussion sample can be specified, which is useful for pitched drums,
like tom-toms.

Like RT.SYNTH (which Seth also offers as DMS Synthesizer) DMS Drummer
uses the DAC522 5-bit 22kHz pulse-width-modulation wavetable synthesizer
engine, driven by a sequencer that runs in real time.  DAC522 represents
"silence" as pairs of 6 cycle pulses spaced 46 cycles apart, regardless
of whatever the code is doing--which subroutine it's calling or which
branch path it's taking.  Executing "branchy" code while maintaining
a constant stream of evenly spaced pulses is pretty tricky, but it must
be done if the sequencer is to keep silent except for the desired
sounds.

Seth is offering the full version on his website:
   http://www.8bitweapon.com/store.htm
for $15, but the demo version (downloadable both from my website
and his) is free for you to play with!  It is limited to 8 distinct
programmable patterns and the Save function is disabled.

Listen to the sample song, created by Seth, on either of our websites
to hear the realistic rhythm line that an 8-bit Apple II can produce!
The melody and bass lines are being played on RT.SYNTH, so the only
non-Apple II-produced sounds are the "explosions" (which could also
have been played by SOUND.EDITOR on an Apple II!).

-michael

DMS Drummer for more rhythmic Apple II computing!
Home page:  http://home.comcast.net/~mjmahon/

"The wastebasket is our most important design
tool--and it's seriously underused."