GM Arts Firmware for BJ Devices TB-12
  User Guide

Where Are My IAs?

IA is a term sometimes used for MIDI messages that toggle an effect on and off. There is no such thing as a MIDI IA message, so I use the correct term: CC for control change. This is also more applicable to my firmware that can send any value for off and on.

Controlling Effect States

Effect states are set like this:

• If selecting a patch, any persistent effects will keep their off/on state from the previous patch, other effects will set their initial state set for the patch and send their off/on messages if set to "always send after a patch change".
• If backtracking with effects, all effect states (including Tap Effects, if used) will be set as they were in the backtracked patch.

There are different ways to use these settings to control which effects are on and off when selecting a new patch. You can even use different methods for each effect.

This MFC can fully control which effects are on and off when selecting a patch. To do this:

• On the Patch Numbers tab, set the initial effect states for each patch however you want
• On the Effects tab check "Always send effect state with patch change" for effects that you want to force off or on, to match their initial settings.

Even though this means you need to keep your effect states synchronised with your patches, there are many benefits to this approach:

• The MFC displays effects in their initial states when you select a patch. That way when you press an effect footswitch it will correctly turn the effect off or on. You won't have to press a footswitch twice to get it to synchronise with the way your patch is set.
• The MFC "knows" what the normal effect states are, and indicates (with a flashing patch LED) when you've changed effect states. You can then press the patch footswitch again to instantly reset your patch.
• There are no surprises playing live, even if you accidentally save a patch with the wrong effects off and on. Recalling them with the MFC will always set the effects that you want and expect.
• You can set up several MFC patches with the same MIDI program, but with different effect combinations in the same program on your connected equipment. This is similar to scenes on the Axe-FX, but you can a large number of them, with even more options in advanced mode.

You don't need to set "Always send effect state with patch change" for every effect, but you will lose some of the benefits from the MFC "knowing" what initial states should be.

Getting Effect States from the Axe-FX

If you own an Axe-FX, you can have the Axe-FX set effect states on the MFC. To do this:

• On the Effects tab un-check "Always send effect state with patch change" for all effects
• Use effect CC values 0 for OFF and 127 for ON (you can use them oppositely if you wish)
• On the Other tab for Axe-FX, check "Get Block States"

This works for very basic on/off effects and may be all you need. The MFC will learn initial effect states as you use patches, so they don't even need to be set correctly in Patch settings. It will identify which effect is which by the effect CC message with a matching CC number, and set it to off or on by looking for values 0 and 127.

There are some disadvantages of this method, in addition to missing some of the benefits listed above. The Axe-FX only sends basic effect state information. It won't be able to show effect states on the MFC:

• If you use a footswitch to toggle between different levels, such as OFF for a low ambient reverb level and ON for a higher "big reverb" level. In both cases the Reverb block is on, so the Axe-FX can't tell the MFC whether your "big reverb" reverb effect is off or on.
• Some effects, such as the mixer, don't even have an off state, so there's no way to show any changes you might make with these effects.
• You might use a footswitch to change settings in multiple effects, such as boosting delay feedback and also changing rotary speed. This type of effect modifier doesn't correspond to a simple on/off effect.
• An effect might change relay states or send system exclusive messages, so again, the effect information from the Axe-FX won't be able to tell the MFC what's off and on.

Why Can't I Choose CC Numbers 0 and 32?

Well firstly, the MFC does send CC message numbers 0 and 32 - they're the MSB and LSB bank numbers on the MIDI tab. They are used to access more than 128 patches on connected equipment.

CC numbers 0 and 32 are reserved for MIDI patch banks and are not available as effect controller numbers. Using those numbers for effect controllers can cause unpredictable patch selection in connected equipment. Any other number from 1 to 31 and 33 to 127 can be used.

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