"Jam Man" (U): Text schematic for the creation of an algorithm with the idea of implementing a sampler/playback loop similar to the JamMan. Paride Zizzari 11/5/1996. 
TXT 
From: 	Paride Zizzari[SMTP:paride@maranatha.gland.sgi.com]
Sent: 	Tuesday, November 05, 1996 5:31 AM
To: 	gsp-users@portal.com
Subject: 	Jam Man Emulation


 As promised last week I am posting here an article on how to emulate
a Jam Man box. Before you read further and jump on your 2101, keep
in mind that this is an emulation and you will not find all the features
of a Jam Man here. In particular I have no idea how to hack real tap-tempo
delay. Hints welcome.

However you will be able to :

	- practice improvisation over chord changes
        - record two parts guitars (2 sounds)
        - create interesting loops and textures
        - overdub at infinitum
	- correct some type of mistakes


You need the optional foot controller and a second S-DISC to reach
full benefit of this algorithm. One S-DISC will get you only 5 seconds
delay.

So here we go:

#=================================================================
#HEADER SECTION
#
GSP-2101             #Device ID
2.00.00              #Software version
Jam Man              #Program Name
xx                   #Algorithm number (whatever u want)
#=================================================================
#                   Comments, Please!
#                   paride@gland.sgi.com
#=================================================================

     a)            b)          c)      d)        e)       f)         g)

                                        +----------+
                              +---+   +-+-+        |               +---+
               +---------+    |   |   |   |   +-------+  +------+  |   |
	    +--| SOUND 1 |-+--|2x1|---|2x1|---| DELAY |--| P.Eq |--|
  |---
            |  +---------+ |  | A |   | B |   +-------+  +------+  |   |
    +---+   | left         |+-|   |   |   |                        |   |
--- |2x2|--+               || +---+   +---+                        |   |
--- |   |--+               ||                                      |   |
    +---+   | right        ||                                      |
  |---
            |  +---------+ +|--------------------------------------|   |
	    +--| SOUND 2 |--+--------------------------------------|   |
	       +---------+                                         +---+


a) This is the input section. To allow two sounds to be processed I use
a 2x2 mixer acting as a splitter :

    2x2  <- ( Left Input, none)
            (100, -50 [CC1 -50-50], 0, 0 )

 We don't need the right input. Link CC1 to switch -50 or 50,
thus when CC1 is off the signal goes to SOUND 1 and when it's on it goes
to SOUND 2. You can also use CC4 (pedal) if you like to mix in between.


b) SOUND1/2 are the modules that you like to have to produce the
  two sounds. Note however that if you use all the memory available for
  the delay, some effects (like reverb) will not fit here. You will
  have to reduce the delay time.

c) This mixer collects whatever was comming from the 2x2 mixer :
    2x1A  <- (SOUND1 out, SOUND2 out)
            (100,100,0 CC2 [0,100])

   The output of the 2x1A is linked to CC2. If you link CC2 to a
   patch number and have it switch between 0/100 it will act as your
   record button. When set to 0 no more sound goes into the DELAY
   section. If the level is set >0 the sound is written into the delay.

d) This mixer mixes new incoming sound with the DELAY.

    2x1B  <- (2x1A, DELAY out)
             (100,100 CC3 [0-100],100)

   Again CC3 here serves a on/off switch. It set to 0 the sound
  going into the DELAY will be repeated once. If set to 100 it will
  loop forever. Since we are in the digital section, there is no
  loss of quality. You can also decide to use CC4 (pedal) as a fader.

e) The DELAY section holds the signal. If you want to use the 10
   seconds available you have to daizy chain the delay modules
   one on each S-DISC.

       delay1 : 5 s. -----> delay2 : 5s

f) The parametric equalizer is optional. I found out the digital signal
  to be too cold so I have added a bit of bass to warm it up.

g) This is the final mixer. Obvious


That's it. Enjoy and tell me if you would like me to post more of
these emulation patches.

Bye
Paride


-- 

"Minds are like parachutes...they function best when open."
- What if we had no imagination ... ??? 
- We'd never say 'what if ...'
              _
         .o`     `o.           .   ZIZZARI Paride 
      ,o             `o       "    Silicon Graphics 
     o                  `o  o"     Project Eng./Manager
    o                     `oo      Les Avouillons 30/1196 Gland
     o                   o' o"     Switzerland 
      `o              o`     ".    paride@gland.sgi.com 
         `o.  _  .o `          "   Mail stop : IGE-304 

http://reality.sgi.com/employees/paride_gland
Phone 41-22 999 9494  Fax 41-22 999 9498  
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