Re: Help! JamMan Pedal Problem

[miguel.barella@poyry.com.br (MAT)]

     Here is some information about JamMan "clicks" written by Bob Sellon:
     
     
     Message was resent -- Original recipients were:
     To: Loopers-Delight <Loopers-Delight@annihilist.com>
     
     
     There are two possible causes for the noise I can think of; one you 
     can   fix the other you can't.
     
     
     When Jamman is slaved to an external MIDI clock it determines the   
     end
     of   the loop by itself based on the tempo of the clock and the   
     number
     of   beats selected on the front panel. If the operator tries to end  
 
     
     the loop   manually, the resulting loop will very likely be shorter 
     than it should   be. When the loop is too short, Jamman restarts the  
 
     
     loop twice: once when   the end of the loop (time) is detected and 
     once when the correct number   of MIDI clocks has come in. The 
     solution is to let Jamman close the loop   by itself (DON'T tap a 
     second time). This will get the loops size to it's   best fit.
     
     
     The second cause is based on the jitter on the incoming MIDI clocks 
     and   the resolution of Jamman itself. At best, Jamman can lock in a  
 
     
     loop size   to within half a millisecond (512us). The problem is   
     that
     most MIDI clock   sources have jitter (timing variations) in the   
     same
     neighborhood. After   the loop time is locked in, the priority in 
     Jamman is to stay in perfect   sync with the incoming MIDI clock.   
     The
     problem is that the combined half   millisecond resolution of Jamman  
 
     
     and the jitter on the incoming clock   result in the actual size of 
     the loop changing very slightly every time   through. As the loop   
     size
     changes, Jamman either shortens the loop or   replays the very 
     beginning of the loop to compensate resulting in   potential clicks 
     and pops. With the PC itself being slaved the jitter   gets worse   
     and
     so do the clicks and pops.
     
     
     As I said, there is currently no work-around for this other than, as  
 
     
     you   said, not playing anything at the loop edge. The only other 
     thing I can   suggest (which is equally klugey), is to place   
     something
     percussive at   the splice point which will tend to mask the noise.   
     I
     am looking at the   problem, however, and will let you know if I   
     come
     up with anything.
     
     
     If anyone out there has any suggestions on how to deal with this,   
     I'd
     love to hear it.
     
     
     Bob Sellon
     Lexicon/Stec
     bsellon@lexicon.com
     
     
     --------------------------------------------------------------------- 
 
     
     


___________________________ Separador de Resposta 
______________________________
Assunto: Help! JamMan Pedal Problem
Autor:  Drumworker@aol.com na internet
Data:    30/10/1997 14:01


I am finding that the pedal suppled by Lexicon (with the JamMan) produces 
an 
audible "click" in the output when I tap it to close a loop. This seems to 
happen about half the time and does not seem to relate to how hard I press 
it. Could it be dirt in the switch? Any ideas how to correct this anyone?
     
Also - if it's simply that the pedal is "not the best" quality - can I 
replace it with another type of pedal  that will operate the Tap function 
silently?
     
Any and all help re. this is appreciated.
     
P. Ormandy
"drumworker@aol.com"