Why does Reverb mix parameter at 0 mutes block in 4CM setup?

Loss Mentality

New Member
I recently got an AXE FX III and am setting up a preset for using a real amp via the 4CM.

So the connections are: guitar-> I1 -> O3L -> Amp In -> Amp FX Send -> I3L -> O4L -> Amp FX Return

And then I created a preset that just has the above I/O blocks. All is well.

Now I'm experimenting with dropping a reverb block into the amp's FX loop, so between the I3 input block and the O4 output block on the grid. I'm using Axe Edit to do all of this.

My amp's FX loop can be set for either parallel or serial, so I start experimenting with the amp's serial FX loop mode, in which case I want to be able to control the amount of reverb by setting the AXE reverb block's mix parameter. What I've noticed, however, is that the reverb block's mix parameter is controlling the output level of the block instead of the mix. As in, no matter where I set the mix, the sound seems to be all reverb, and the mix is instead controlling the block's output level. Thus, if I set that mix to 0%, the block has no output, which I can verify by going into the mode where meters for all blocks are shown on the AXE front panel GUI. As I turn mix up from 0 to 100, I see the output meter showing no output at 0, and then increasing output as I move mix to 100.

Now, if I drop a reverb block in front of my amp (i.e. between I1 and O3), the mix parameter behaves as I'd expect: it just sets the amount of reverb in the signal, without impacting the output level.

So I got to thinking, is the AXE somehow understanding the reverb block in the amp FX loop is in parallel and thus maxing the mix parameter work differently? Well, I tried going to normal AXE preset (so my amp's not being used, just guitar -> I1 -> O1 -> FRFR speaker). And I set up a reverb block in parallel to the main signal chain, but here the mix still behaves as I'd expect (i.e. mix controls the amount of reverb in the signal/0% mix doesn't mute the output).

So the main difference between my preset for the physical amp vs the preset for the FRFR is that the former has multiple inputs and outputs in use on the grid and the reverb block is not taking input from input 1.

Can anyone confirm this behavior? Am I missing something? Doing something dumb? If I want to use my amp's fx loop in serial mode, it would seem I need to be able to control the mix of the AXE blocks sitting in the amp fx loop, but as it stands, mix is essentially acting as an output level control, not a mix control. Of course, for parallel, I would have the reverb's mix at 100%, and the reverb's output level parameter does still impact its output volume, so that would be workable.

I've done a lot of googling to see if I can find something about this, but I can't, hence my first post here on this forum.

Thanks!
 
Apologies, @2112, for taking so long to reply - haven't had a chance till today to get back to this issue.

I had posted a simplified setup in my previous note for the sake of brevity, but it seems my actual setup had something to do with the issue I described. The full setup is actually two amp heads, each using 4CM with the AXE, and as I've juggled the combinations of R and L on Input and Output 3 and 4 that I'm using for each amp, I've resolved the reverb block mix issue. I now need to redetermine how I want to run the cables to both amps and see if the reverb issue stays resolved.

It's still not obvious to me why I had the problem in the first place, and I might yet come back to discuss that. But I want to poke around a bit more first to see if I can achieve what I'm aiming for. Even if the reverb mix issue is fully resolved, I'll try to post back a full description of 4CM for two amps when I'm done as I haven't seen a lot online describing a setup meant for using two amps independently via 4CM.
 
I'd guess you were using one L and one R jack for the In 3 and Out 4 connections to that amp. The actual reverb engine is fed a mono sum of the block input, but your dry signal would have been in the opposite channel and not heard. Or, possibly using both R jacks while having In 3 mode = stereo and Out 4 mode = Copy L>R.
 
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