1. There is a predefined list of controllers you can use to realtime-control
- two predefined (of the up to 12) EFX-parameters and
- some definable patch-parameters.
DISADVANTAGES: They only work, when - set to the same channel as SYSTEM>CtlChannel (fact.preset = 16)
- therefore they can only be used once in the Performance and
- they may conflict with the main function of the controller (e.g. when using CC 7 which is part of the predefined list).

2. There is furthermore the possibility of choosing SysCtl1 and SysCtl2.
ADVANTAGES:
- They need not correspond with SYSTEM>CtlChannel and can therefore be set (up to 16 times) to controll the parts of your performance(!)
- You can define any Controllers (eg GeneralPurpose1 = CC16, GeneralPurpose2 = CC17) so they can�t get into conflict with other controllers.
DISADVANTAGE:
You only have two of them.

3. Therefore I decided to use the following setup:
- As one can use EFX only once in a performance, I have choosen those two of the predefined controllers I don�t use at the moment (breath = CC2 and foot = CC4) to control EFX and set SYSTEM>CTLCHANNEL to Channel 16 as well as the controllers send channel.
- So I saved the much more powerful SystemControllers for "Patch-Work": I set SYSTEM>CtlAssign1 to CC16 and SYSTEM>CtlAssign2 to CC17 and I set for all parts/patches PatchCtl2 to SysCtl1 and PatchCtl3 to SysCtl2 (remember that you can�t change PatchCtl1 from Mod. to another ControlSource).

4. But all this does�nt work if you forgot to set the effect-depth away from Zero (this is the number after the controller you chose and it works like this: eg depth = +20, that means: Sending a CC-value of 0 gives you the original tone, sending a CC-value of 64 adds a value of 10 to the effect etc. or you set depth to -10, that means: Sending a CC-Value of 127 substracts the amount of 10 from the effect).

Note: This text is copied from http://home.cybertron.com/~brtubb/text/048.txt However, given that many sites on the JV/XP-Synths ceased to exist, I decided to copy it cause i think it is very useful and shouldn't get lost.