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RE: jammidimystery

I'm not familiar with the term "brothersync". Are both systems sending
sync information to eachother?

Regardless, the JamMen can't be configured to cleanly work in stereo.
Unfortunately, it was not considered when the product was spec'd and
designed, wasn't tested in-house and apparently doesn't work. When asked
about this before, the only suggestion I could come up with was to feed
the MIDI commands to the two independent systems in parallel and run
them open loop. The lock in this configuration is coarse at best however
due to the lack of a synce between systems and the latency of the
system's response to incoming MIDI commands. It's been a few years since
I looked at it but I suspect that using MIDI commands could decrease the
responsiveness/resolution by as much as 10ms (it may very well be less)
compared to standard JamMan resolution of 0.5ms. With 10ms of slop, it
won't take long to hear the delta. In the best possible case, the
systems will never be locked at a sample level so there will always be
drift and you will not get proper stereo imaging (even briefly I

Regarding the odd behavior; I suspect that, as Greg Hogan suggested, the
second system is attempting to slave to incoming MIDI clock so it
ignores or misinterprets the second tap. During product development
there were precious few systems available so not a whole lot of
multi-unit testing was done. Apparently systems are not supposed to
"soft" thru MIDI data but we added it in fairly late in development
anyway so that 2 JamMen could be used together without a MIDI
merger/splitter (albeit not in stereo). Part of the problems with trying
to cascade the JamMen (brothersync?) is that the CPU in JamMan that
handles MIDI (a measly 4MHz Z80) also has to manage the realtime looping
without missing a beat. The audio and MIDI clock are the highest
priorities so MIDI thru operations can be delayed (the aformentioned

I wish I had better news but thats the way it is. Sorry.

Bob Sellon

> ----------
> From:         Phil Diem[SMTP:pdiem@edcen.ehhs.cmich.edu]
> Reply To:     Loopers-Delight@annihilist.com
> Sent:         Tuesday, September 16, 1997 12:15 AM
> To:   bsellon@lexicon.com
> Subject:      jammidimystery
> Has anyone else had problems brothersyncing two jammen via midi?
> Yesterday I converted to midi control by connecting a DMC Ground
> Control 
> (v2.4) to two jammen. I programed the GC to transmit on ch 1 and
> loaded 
> the presets to send the correct midi program change numbers. When I
> tap 
> in a loop: 
> 1. sometimes jam #1 starts recording solo and when I tap out 
> #2 starts recording immediately 
> 2. sometimes they both start recording 
> together on the first tap (this is how I expected things to work) 
> 3.sometimes #2 doesn't start recording until the third tap (with #1 
> layering). 
> There seems to be no predictable pattern and I never know 
> which sequence I'll be dealing with until I get into it. And 
> unfortunately, reset works fine and resets both units simultaneously.
> Tonight, I unhooked the GC but left the jammen brothersynced, and
> tried 
> using the lexicon footswitches to control them. Surprise! The lexicon 
> switches didn't work properly either.
> Tap out required 3-7 taps before recording would stop and the loop
> would 
> start playing???
> I tried switching the sync cable; in to out on #1, and out to in on
> #2, 
> no change. I tried a different midi cable and still no change. When I 
> went back to no midi cable - unsynced - the lexicon footswitches
> worked 
> properly. The GC also works fine with either jamman individually.
> So I don't have a clue as to what's going on, or why. Any helpful 
> suggestions will be very much appreciated!
> Phil