[sdiy] MIDI to CV question - no Triggers?

[Michael Bacich]

On Mar 4, 2006, at 9:51 AM, D A F wrote:
Yes, I guess the problem is: What happens when you are holding one  
note and
then press down a second note without letting the first one up?

This would not be an issue when using the MIDI-CV with a polyphonic  
MIDI guitar controller.  Although the guitar is a six-note polyphonic  
instrument, guitar strings are inherently monophonic.  That is to  
say, on a guitar,  it is not possible to play two notes  
simultaneously on one string.  Or potting it another way, you can't  
"press down a second note without letting the first one up".

Typical guitar-to-MIDI controllers (such as the Yamaha G50 and the  
Roland GR units) transmit each string's note information on a  
separate MIDI channel, which would necessitate the use of a separate  
monophonic MIDI-CV converter for each string.  Such a system would  
also require hardware for six complete analog synthesizer voices.   
This may explain why we don't often see people using guitars as  
controllers for their analog synth gear.

If you wish to use the guitar to play a monophonic analog system, you  
will have two choices:  Either you must restrict yourself to playing  
on only one string, or you must re-channelize the six-channel MIDI  
info coming from the guitar so that it all comes out on the same MIDI  
channel.  This could be done with some kind of external MIDI  
processing device, such as a MOTU MIDI Time Piece II.  However, this  
would necessarily open up a stinky can of Pandora's Worms, in terms  
of some potential MIDI problems and some note and trigger assignment  
problems -- for instance:  What happens if you play two notes at  
once?  What happens if you play a note, then the same note on two  
different strings?  What if you don't completely release the first  
note before hitting the next?  Which note takes Note-On and/or Note- 
OFF precedence?  Which note's Velocity takes precedence?  What if you  
bend a note or notes? And getting back to the original question, what  
happens with triggers and gates if you press a second note without  
letting the first one up?  ...there are other potential problems, too.

Harry Bissell has opened that can of worms many times, and has come  
up with various solutions for most of the inherent problems -- none  
of them involving MIDI, though.  Check out his "Muffy" guitar to CV  
converter for more insight:

http://www.bitshifted.com/SDIY2004/muffy.asp


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