Stange phase/delay issue with dual amps/cabs

j_texas

j_texas

Member
When running 2 amps in parallel, I'm getting a very noticeable delay in my right channel (split hard L/R).

IR's are from the same library, so not out of phase. I've even checked the alignment.

Additionally, even if I run 2 amps in parallel into the same cab block (stereo input) I get the same result.

Anyone have this issue? It's really unusable. So, I just run 2 amps in mono and it sounds fine. It only sounds strange when I pan hard left and right.
 

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Why are you using two cab blocks instead of one? Not criticizing. Curious as to rationale since I run two amps through one block, and pan hard L/R in it.
 
Guys, I think I have it sorted. When I choose Left only input on Amp Block 1 and Right only input on Amp Block 2 and then pan each Cab Block, it seems to be ok. So, it won't help to upload that preset. I'll try and recreate what I was referring to originally and then upload it.

@CactusTone the reason is because some cabs work better for different amps.
 
OK. Here it is. Was going for a wet dry thing.

When I turn on either drive... that's when it sounds wonky. Both drives and it's really apparent.

EDIT: This is the non-L/R split version.
 

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The first thing I see is that the Reverb block has a 40ms predelay. That's enough to be noticable.

Changing the lower path so it rejoins just prior to the first REVERB block gets rid of the phasing/delay sound. To me it's tighter and clearer, but YMMV.

The second thing I noticed was it was boomy. I changed the low-cut on CAB 2 to 80 on both cabs, and that tightened up the sound. That might not be what you want as I'm using some Audio Technica headphones that have a bit of bass boost so they might be over-emphasizing the low end. Also the bass seemed a bit flabby on AMP 1 so I reduced the drive to 6, which tightened it up, then adjusted the levels, which ended up with AMP 2 level at 2.88. Again, that's my taste, but at stage volume I think it'd sound pretty good.

The changes are attached.
 

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Greg Ferguson said:
The first thing I see is that the Reverb block has a 40ms predelay. That's enough to be noticable.

Changing the lower path so it rejoins just prior to the first REVERB block gets rid of the phasing/delay sound. To me it's tighter and clearer, but YMMV.

The second thing I noticed was it was boomy. I changed the low-cut on CAB 2 to 80 on both cabs, and that tightened up the sound. That might not be what you want as I'm using some Audio Technica headphones that have a bit of bass boost so they might be over-emphasizing the low end.
Click to expand...
Nice. Thank you very much for listening.

I wonder if you heard everything going out of phase when the drive blocks were engaged? Drives off and it sounds lined up, but when you turn on those drives it just falls apart to my ears.

EDIT: I just saw where you said changing reverb path fixed it. Sorry. Thanks again.
 
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Adding a DRIVE block in front of only one of two AMP blocks in parallel rows, with both AMP blocks engaged, can indeed cause phase cancellation, because of timing differences. Solution: add a bypassed Drive block to the other row (at the expense of CPU).
 
yek said:
Adding a DRIVE block in front of only one of two AMP blocks in parallel rows, with both AMP blocks engaged, can indeed cause phase cancellation, because of timing differences. Solution: add a bypassed Drive block to the other row (at the expense of CPU).
Click to expand...

Thank you! Makes total sense. I will check that out when I get hone.
 
yek said:
Adding a DRIVE block in front of only one of two AMP blocks in parallel rows, with both AMP blocks engaged, can indeed cause phase cancellation, because of timing differences. Solution: add a bypassed Drive block to the other row (at the expense of CPU).
Click to expand...
That's exactly what it was.

Although, I didn't have luck with the Drive block in bypass. I got the same result. I ended up putting a transparent style drive in front and matched the gain. Sounded great. No phase issue.

Additionally, I had to remove the second Drive block from Row 1.

Before, I had a drive feeding into another. There are only 3 Drive blocks available, so if there was a mismatch in number of drives, I ended up with the same result.

I could have one drive feeding the 2 rows before the split, but not two in Row 1 and just one in Row 2.

Thanks all for the help.
 
yek said:
Adding a DRIVE block in front of only one of two AMP blocks in parallel rows, with both AMP blocks engaged, can indeed cause phase cancellation, because of timing differences. Solution: add a bypassed Drive block to the other row (at the expense of CPU).
Click to expand...

j_texas said:
That's exactly what it was.
Click to expand...
I'm confused based on the screenshot that was shared. Is that not matching the actual preset? Because the screenshot shows 2 Drive blocks before both amps...
 
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