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hankmadison

FX Loop Phase Issues?

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Anyone will to test this with your Helix? 

 

I've got an SM7 connected to the Helix via the mic input. I have nothing in the signal chain -- no blocks. Healthy signal running to Logic. All sounds good.

 

I pulled out my old RNC compressor and put it into one of the FX loops. I notice that when I make the FX Loop block active (even with the outboard unit on bypass) that I can hear a slight chorus effect and a loss of low end. Sounds like a bit of the original dry signal is getting mixed back in and there's a phase issue. I still hear this when I engage the compressor. When I bypass the FX Loop block the signal is nice and full again.

 

I decided to test this with another "true bypass" outboard unit with different cables on a different FX Loop. I'm getting the same weird phasing issue.

 

I don't use the FX Loops when I'm playing guitar through the Helix so this is the first time I've come across this. I don't have a problem running effects in Logic, but it would suck if the Helix's FX Loops aren't transparent.

 

Anyone else notice this? Thanks.

 

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I've experienced this too when I use my Boss Looper and I wish I could turn off the foldback within the looper.

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I use the FX loops all the time and haven't had an issue. Do you have the mix parameter on the FX Loop block set to 100%?

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I use the FX loops all the time and haven't had an issue. Do you have the mix parameter on the FX Loop block set to 100%?

 

 

Yes.

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Is there any chance that you are feeding a delayed signal through the loops, perhaps the few extra milliseconds delay introduced by a loop in addition to an already delayed signal might introduce some subtle phase cancellation issues? If this were the cause it might still happen even when the effect was bypassed. Also, and probably not the issue as you would not get any sound at all depending on your routing but one thing to keep in mind with the Helix is that the send/return loops inputs are next to each other horizontally, not vertically as they are on many devices.

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Thanks for chiming in. As of now, I simply have an FX Loop block in the chain and I'm hearing this issue. Nothing else is in there. The phasing issue happens regardless of whether or not the external unit is bypassed or engaged. 

 

Mic --> FX Loop block (mix at 100%) --> external unit --> back to Helix and out (Multi)

 

And this is also repeatable in a different FX Loop using a different external unit and different cables.

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The plot thickens. I attempted to record this in Logic. While I was recorded I was monitoring via headphones connected to Helix. I could hear the phasing issue clearly. When I reviewed the recording the phasing issue wasn't there. The FX Loop was transparent. 

 

Any ideas about what is happening here? What is different about the signal going through the headphones vs the signal going through USB to Logic? 

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Do you happen to have a second signal chain where the guitar also goes through it that is dry that could only be routed to the headphones? If so it could be mixing in with the slight delayed signal of having the other signal chain having an FX block on it period. (and the main signal chain is the only one being sent to logic? Are you sure you're not recording the dry track into Logic? Guitar defaults to USB7, VOX defaults to USB8.

 

I'd double check these to things if I were in your shoes.

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If you are hearing it when you're hooked up to logic, I'm guessing you're hearing the signal twice, once direct and once with Logic's latency. That would explain that. 

I always record from Helix into logic withOUT monitoring through Logic (zero latency that way).

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If you are hearing it when you're hooked up to logic, I'm guessing you're hearing the signal twice, once direct and once with Logic's latency. That would explain that. 

 

I always record from Helix into logic withOUT monitoring through Logic (zero latency that way).

If it doesn't happen when not connected to the pc then this is what is happening.

 

In FL STudio I just de-route any channel I have incoming guitar being recorded from the master channel in the mixer. Boom. Done, no problem. I am sure Logic has a relatively easy way of doing it as well. 

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Do you happen to have a second signal chain where the guitar also goes through it that is dry that could only be routed to the headphones? If so it could be mixing in with the slight delayed signal of having the other signal chain having an FX block on it period. (and the main signal chain is the only one being sent to logic? Are you sure you're not recording the dry track into Logic? Guitar defaults to USB7, VOX defaults to USB8.

 

I'd double check these to things if I were in your shoes.

 

 

Thanks for the input. There is nothing else in the path. And path 2A is empty as well with no input selected. 

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If you are hearing it when you're hooked up to logic, I'm guessing you're hearing the signal twice, once direct and once with Logic's latency. That would explain that. 

 

I always record from Helix into logic withOUT monitoring through Logic (zero latency that way).

 

Thanks, Peter. I've been unconnected from Logic this whole time. I, too, mute the record enabled track in Logic while recording and monitor through Helix. Again -- this is happening without connection to Logic -- purely monitoring via headphones with Helix. 

 

I only connected to Logic when I was trying to record it. Somehow the USB output is not getting this, but the headphones from Helix are -- regardless of being connected to Logic.

 

Seems like it would be pretty easy to replicate on someone else's system. Is anyone else trying this and seeing if it's repeatable? 

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C

 

Thanks, Peter. I've been unconnected from Logic this whole time. I, too, mute the record enabled track in Logic while recording and monitor through Helix. Again -- this is happening without connection to Logic -- purely monitoring via headphones with Helix. 

 

I only connected to Logic when I was trying to record it.

Can you screenshot the patch? That might help.

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Maybe try trails on? hell it won't hurt lol, but I doubt that is it.

 

You sure you weren't recording a dry track to Logic with USB 8?

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You sure you weren't recording a dry track to Logic with USB 8?

 

 

Nope. When I was recording I was recording USB 1. Again, this is happening without USB connection to anything and only monitoring via headphones.

 

I've opened a support ticket. Thanks for taking a crack at this, guys!

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Thinking maybe you have your headphone output set to monitor all (XLR, 1/4", and usb) and may be getting some phase differences between those sources. I use my XLR set at mic level and my 1/4" at line level with global eq only, so set my headphones only to monitor the flat XLR, and don't hear any phasing issues. Just a thought...

 

Dave

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There was a bug that mixed dry signal to processed signal caused by tuner settings.

Try setting tuner input to 'none' and see if it goes away. Another troubleshooting is to turn fx level to minimum. If you're still hearing sound, you have some unprocessed guitar passing by, which causes not only phasing issues while using fx loops, but also tonal issues.

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Update: When I try to record this phase weirdness out of USB it doesn't happen in the recorded signal. I then tried to record the headphone out (using it 1/4" TRS Y-Cable) into (2) separate inputs in another recording interface. Same thing -- no phase issues. It sounds normal. 

 

Two possible scenarios:

 

(1) I'm crazy (which is debatable) or

(2) Some kind of weird impedance thing happening with the headphones? 

 

Not sure. Bottom line is that it's not affecting the output signal so I can track with this and know that it's not affecting the final product. Curious if anyone else ever runs into this. 

 

FYI -- I'm only hearing it through the mic input. I don't hear this when a guitar is used as the input device. Thanks to those that chimed in.

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