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My Ultimate Atari8 MIDI Rack

Posted by Pack007, 02 May 2017 · 134 views

I was getting a second Atari 8bit operational to use as a MIDI SynthDrum sound module controlled by the first running the MIDI MUSIC SYSTEM and MIDIMAX,  when I had to leave for a babysitting gig in Rochester.  I knew I would have some free time and took a pencil and paper to sketch out a plan for my ultimate 8-bit MIDI rack.
At the end of the day the sketch looked like this.
Attached Image
The control computer with the MIDI software transmits MIDI data to several Arduino processors with MIDI shields.  A MIDIjoy with a THRU port is one way to accomplish this.  The interfaces will be able to read the MIDI data stream and filter out the data for a given channel/computer  and send it to an Atari by way of the joystick port.  The Atari can then set the audio channels to create the desired sound. (16 MIDI channels * 4 POKEY audio channels = 64 notes).
At some point in this endeavor I would like to have all the Atari programing on the MAXFLASH cartridge. If the program is near self loading the need for a monitor and disk drive for each computer can be eliminated.  I guess until then its going to be a "plug-and-unplug-and-play" setup.
Although the drawing is limited to Atari 8bit computers, there is no reason why a 2600 or Atari ST couldn't be added to the rack.  Would a C64 or Game Boy add anything to the mix?  According to Wikipedia, a MIDI keyboard and Yamaha TG33 could be added to the rack; as long as there is one 8bit source, the music could be considered (by some) a chip tune.
(Random thought: Could SAM be made to sing under MIDI control?)
The audio from each computer will need to be combined using an audio mixer.  A Behringer XENYX 1202FX mixer has been purchased and received.  It has 12 inputs(4 mono, 4 stereo)  and a 24-bit Multi-FX Processor.  It fit my price range, had the number of inputs I wanted and seemed to be highly rated. 
(Random thought: When an 8bit audio signal is sent through a 24bit processor, is it still a 8bit chip tune sound?)
The audio from an Atari 130XE was hooked up to the mixer and then the output of the mixer hooked up to a Windows computer for recording. Audacity has been used to record the Atari playing .AMS files. The MP3 files and original AMS files have been included in the following ZIP file to demonstrate the difference.   I may have gone overboard with the FX processor, mixing is a balancing act yet to be mastered.
Attached File  AMS to MP3.zip (14.1MB)
downloads: 4
Who knows how close I will get to creating music worth listening to or how far the rack will deviate from its original concept.  Its going to take a long time and am hoping to still have my hearing when its finished.
As a recap, in the last blog, a MIDI keyboard was hooked up to the Atari running the MIDIfied Synth Drum program.  Next step will be to program some drum pattern tests into MMS and then output them to a second computer running SynthDrum for timing tests(what's the limit of a BASIC program?). Then a third computer will be added to generate a second drum sound. And then…..

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