From bw@ashbysolutions.com Sat Jul 27 13:34:03 2013
Subject:Re: Analog Outfitters ORGANic 261

My $0.02USD ...

Not only isn't there any available clone that can accept 9 switches
worth of data, but the current MIDI data specification -- i.e., MIDI
over the 5-pin DIN jacks -- would be hard-pressed to handle the
results. I've experimented around with duplicating data on multiple
MIDI channels, and found that most MIDI devices start to run out of
'instantaneous bandwidth (IBW)' -- i.e., the ability to handle messages
coming in at real-time rates without thinning or dropping data -- at
around 4-5 channels. Some MIDI devices can't handle three channels.
[For the technically minded, read on ...]

MIDI can send/receive 3,125 bytes per second. Each Note On (NON) or
Note Off (NOF) takes three bytes, so that's about 1,040 notes/sec. --
except that in certain playing styles like palm smears, a NON is likely
to accompany a NOF for another key; so let's say half that many: 520
notes/sec. Now, that *sounds* like an incredible amount of notes,
right? Well, it isn't as much as one might think. What it says is that
the data packets need to be staggered at least 2mS apart; or the MIDI
system has to buffer up the extra messages until it can handle them. CC
messages also dip into that pool, and the Expression pedal can send out
a lot of data on stabs, too. Ultimately, it works out to more like
5-6mS apart -- and that assumes that the receiving device can handle any
number of messages thrown its way. It turns out that, in practice, an
average MIDI setup can't do so.

I stumbled across this situation accidentally. I had a complicated MIDI
setup where the organ sounds were on CH1, CH2, or CH5, depending on the
program. I figured that I could just use a MIDI Solutions box to
duplicate the Expression pedal on the three channels. It worked -- most
of the time. Sometimes, though, when I was soloing with palm smears, I
got stuck notes. Investigation showed that the MS box was sending all
the data, all the time. So, the only conclusion I could reach is that
the received data was too much to handle when the notes are coming fast
and furiously.

Now, USB MIDI might be a different story, but in the 'legacy' MIDI
world, it's definitely a problem. Nine key contacts would never fly.

Regards,

-BW

Bruce Wahler
Ashby Solutions.com™
bw@ashbysolutions.com
http://music.ashbysolutions.com
877.55.ASHBY (877.552.7429)