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Voodoo Lab Audio Switcher GCX + GCP


New Member
I'm just transitioning into using the AxeFX II (Mark 2) into my live rig. I play in a Metallica cover band, so I require going from clean to heavy sounds pretty instantaneously, but I've found when I switch scenes there is latency during the switch. What would be the best remedy? I have another Mark 2 as well, so maybe run them both? One for clean one for heavy, and then use the GCP as a A/B pedal?
Or would I use the midi function to control the 1 AxeFX?


New Member
If you don't use dual amps for your sounds you could use one for clean and one for dirty sounds within a single patch and use scenes to switch between them. That should be completely gapless.


Yes, run 2 amp blocks in parallel.

Set Bypass Mode on both to Mute.

I'm assuming you're changing from clean to dirty via X/Y on the Amp block? That will incur a short audio gap so you want 2 Amp blocks.

Andrew Male

Like Unix-guy said, If you can get away with just two amps, e.g. JC120 for clean and the IIC++ for dirty you can run both in parallel in one patch and use scenes between the two where you just bypass mute one on each scene. Pretty Simple.

Your only other option like you said is to run the JC120 from one Axe and the dirty sound from the other Axe, and switch using the GCX, that's what Metallica actually used to do (precisely because of the latency preset issue). That also allows your dirty sound to have the IIC++ and the VH4 (I believe that's the current Metallica live sound).
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The XY gap wouldn't be so bad if FAS would fix this awful slow fade.


I devised a way to counter the fade here: https://forum.fractalaudio.com/threads/various-presets-tricks.135770/post-1630877

This was actually faster (for most but not all amp types) than Axe III amp channel switching as recently as a few months ago. I'm not sure how much the gap was reduced with recent III updates.

Here's the terrible fade in action. (0:40) Apparently they're switching amp XY state or possibly presets for that one descending 3rds measure.



Two Amp Blocks. In parallel. Make sure both amp blocks stay on the X (or Y, whichever you choose) state for every scene. Here's an image I found on Google with two amp blocks in parallel so you can see. They can share the same cab block. The red arrow is pointing to the X/Y state buttons. Try this and it will be exactly what you need. I do this for my band and my scene changes are instant.

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