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HX Effects, 7 Cable Method, Mixer "Inverted"


b418me
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So I am running the Helix Effects with the 7 Cable Method. I am using FX Loop 1 and FX Loop 2 in a Split Path. Before the Split there are only mono effects. After the Split stereo effects. The Mixer is panned 100% left and 100% right. I was wondering: when I change the "B Polarity" in the Mixer from normal to Inverted the overall sound is (much) better ("more bass"). In the manual it says "Typically, this should be set to "Normal."" My question: can I just leave it with "inverted" or is there for example a wiring or DC problem that I should focus on? I am afraid that the sound might change again in a different gig location. Then again I don't quiete understand what the B Polarity really means. Maybe someone can help. Thanks!

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OK, attached is the preset. I am running it like this:

 

Guitar into Treble Booster info Wireless into HX Effects Input Left. Then

Send 1 into Amp 1 Input and Amp 1 Send into Return 1 HX and HX Out Left into Amp 1 Return into Cab 1 (Celestion Vintage 30)

Send 2 into Amp 2 Input and Amp 2 Send into Return 2 HX and HX Out Right into Amp 2 Return into Cab 2 (Celestion G12H 70 anniversary)

I also have an expression pedal and midi footswitch attached to the HX Effects.

Both Amps are Vox MV50 AC.

 

One more thing: in the patch you see a ping pong delay after the Loop. When the loop B Polarity is normal the delays left and right sound thin and distorted. When B Polarity is inverted it sound fine.

 

Thanks!

 

Sound.hlx

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In your SPLIT Block try panning Path A hard left and Path B hard right.

I don't have the HXFX (Floor and Stomp), so I can't test this, but it's the only thing I see that I'd do differently, and since there's no stereo FX before the split it shouldn't matter, but can't hurt.

 

I don't know much about the polarity thing, but the only reason I'd see to reverse it would be if your speakers had different polarities (one pushing when the other is pulling) but since your amps are identical that shouldn't be an issue, so check your cables and the connections at the speakers in case something might be reversed.

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On 9/18/2022 at 5:27 PM, rd2rk said:

In your SPLIT Block try panning Path A hard left and Path B hard right.

I don't have the HXFX (Floor and Stomp), so I can't test this, but it's the only thing I see that I'd do differently, and since there's no stereo FX before the split it shouldn't matter, but can't hurt.

 

I don't know much about the polarity thing, but the only reason I'd see to reverse it would be if your speakers had different polarities (one pushing when the other is pulling) but since your amps are identical that shouldn't be an issue, so check your cables and the connections at the speakers in case something might be reversed.

Thanks for your answer. I already panned both left and right. I will check the wiring. So the polarity is only a matter of internal wiring/cables and speaker and not DC or other? 

On 9/18/2022 at 5:27 PM, rd2rk said:

 

 

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On 9/17/2022 at 7:10 PM, b418me said:

Then again I don't quiete understand what the B Polarity really means.


Hi,

 

HX Effects Owner’s Manual - page 38 - Mixer Settings.
 

https://line6.com/data/6/0a020a411710a6112a67116f0b/application/pdf/HX Effects 3.0 Owner's Manual - Rev C - English .pdf

 

If you’re running parallel signal paths, when you mix them back together, ideally you need to invert the signal from Path B because were they crossover you would have some frequencies cancelling each other out, which can result in making everything sound thin and lifeless. Polarity (phase) inversion should eliminate this and make things sound as they should.

 

In the past 50 years, IIRC I have only once encountered a pair of speakers that were actually out of phase, and that was simply due to the guy inadvertently sticking the positive and negative RCA plugs into the wrong inputs on his Hi Fi, - easily solved.

 

I once heard of a record producer who would record the sound of an empty vocal booth out of phase before doing a vocal take that was in phase. The theory was, much like a “null test”, when the two takes were mixed into one, the phase cancellation removed extraneous noise - possibly an urban legend, but hey!

 

Hope this helps/makes sense.

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On 9/18/2022 at 5:13 PM, datacommando said:

If you’re running parallel signal paths, when you mix them back together, ideally you need to invert the signal from Path B because were they crossover you would have some frequencies cancelling each other out, which can result in making everything sound thin and lifeless. Polarity (phase) inversion should eliminate this and make things sound as they should.

 

I run parallel paths in almost every preset, with FX, Amps, and/or cabs, and have never needed to invert the phase. Are you referring to using a cross-over split?

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On 9/19/2022 at 12:40 AM, rd2rk said:

 

I run parallel paths in almost every preset, with FX, Amps, and/or cabs, and have never needed to invert the phase. Are you referring to using a cross-over split?


Nope. Possibly a slight misunderstanding on my part - yes, generally you should have the polarity set to normal. Although when running parallel paths it is possible when using some circumstances to have blocks that may create the phase anomaly and then I think that is when the polarity switch is required -(AFAIK Line 6 have never fully explained it’s function).

 

From something I read over on Sweetwater (credit to Craig Anderton)-

  • Choosing Inverted for the B Polarity parameter may give useful effects when the output is mono, but it could also create a thinner sound — listen and decide. 
     

Although, I have not had a look at this preset so it was just a guess that maybe some other time based effect was causing  a phase cancellation. If the ping pong sounded thin and turning on path B polarity fixed it, then it seemed to indicate a phase issue.

IIRC - way back prior to v2.7 there was an issue with a couple of amp models had reversed polarity and when used together in parallel paths the would create phase cancellation, especially when the Path B mixer block was engaged.

 

Oh, hum - one more beer then time to sleep!
 

:-)

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Thanks for the input. Very interesting... So what I did so far:

 

First I used a new patch without any effects and just added the Effects-Loop 1+2 in parallel with the Mixer set 100% left and 100% right. With this setting it stayed the same: better/thicker sound when inverted and not normal.

On 9/19/2022 at 2:18 AM, datacommando said:

Although when running parallel paths it is possible when using some circumstances to have blocks that may create the phase anomaly and then I think that is when the polarity switch is required

So it can't be blocks that are causing it, I would say.

 

Then I checked the cabs. 

On 9/18/2022 at 7:00 PM, rd2rk said:

Thanks for the link. Everything fine here (red=+ and black = -). I also used two different cabs and used all possible configurations with 4 cabs - still the same: better/thicker sound when inverted and not normal. And also: I checked every constellation with including the ping pong delay: every time in normal mode the repeats of the delay sounded distorted, thin and much too quiet (maybe you can argue about the sound in normal and inverted. Maybe it is just my ears but the ping pong delays in normal are 100% not intended). With inverted everything normal.

 

So maybe that is just what it is and inverted is the new "normal"?

 

On 9/19/2022 at 1:13 AM, datacommando said:

If you’re running parallel signal paths, when you mix them back together, ideally you need to invert the signal from Path B

 

But then again: 

On 9/19/2022 at 1:40 AM, rd2rk said:

I run parallel paths in almost every preset, with FX, Amps, and/or cabs, and have never needed to invert the phase.

 

So still, no clue what is going on.

 

The one thing I learned from all this: always have one footswitch assigned to the normal/invert in every patch so that you can fastly switch if needed. OK, if you use the same setup (cabs etc.) all the time it wouldn't be necessary but if you are running into different cabs (maybe share a stage and use the backline there etc.) the normal/inverted-footswitch is, hopefully, a good solution.

 

:-)

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On 9/19/2022 at 2:01 PM, b418me said:

So still, no clue what is going on.

 

Hi,

 

O.K. I downloaded the your preset and as I don't have the HXFX, I loaded into my Helix floor. Also I don't have two external amps and cabs available, but I have lots of other things around that I can stick into an FX Loop. This I what I discovered.

 

I patched in a Mooer Ocean Machine to the Helix L/R FX Send and Returns on the Helix. I turned off both delays and the reverb on the Ocean Machine, just using in as a routing device. In your preset with only FX Loop 1 active, everything is fine and the following stereo Ping Pong delay performs as anticipated, - no problem there. When the second FX loop is engaged, again there is no apparent issue other than the sense of a level increase when adding the second path (psychoacoustics probably) - the ping pong works as normal.

 

What does happen is - when you switch Loop 2 on Path B to "Inverted Polarity", and the Mix Block A & B pan are centred you get total silence. Just like a "Null" test, the same frequencies from both Path A and B cancel each other out. Now, when the Mix Block pan A & B are set to 100 Left and 100 Right and the Polarity is set to Normal then the Ping Pong and 2db boost work, but switch the Polarity to Inverted, you can still hear the guitar, but the Ping Pong delay and the boost on the EQ block vanish completely - just as if they had been switched off on the footswitches, except they haven't. Also, changing the Split Y to Split A/B made no difference. I could, for example, switch on a Reverse Reverb on the Ocean Machine and have that playback through the Left and Right Returns into the Helix Ping Pong and Boost normally, but once again, engaging the "Invert" seemed to make the verb sound thin and the built in Delay and EQ boost were no longer audible. Weirdest thing that I've come across for a long time. As you said "So still, no clue what is going on". Same here.

 

I had quick glance through "The Big Book of Helix Tips and Tricks 1.1" by sometime forum contributor @craiganderton , my guess he would be the man who could best explain what is going on. His book contains lots of references to the "Inverted" polarity setting for special effects such as Blooming Reverb.

 

That's as far as I got with this thing - maybe the fine Mr Anderton will chime in with an idea.

 

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I had another go at your preset. This time I loaded it on my Helix.

 

I set the split block back to center as you originally had it. Sounds better that way.

Since I don't have two amps I bypassed the FX Loops and added a WhoWatt preamp to each path in the split.

I routed the L/R outs to two channels of my mixer and panned them hard L/R.

I added a FS to the INVERT switch on the mixer block.

Essentially, I duplicated your rig except for the different speaker cabs, which shouldn't matter for this experiment.

I now have Path A on my LEFT monitor and Path B on the RIGHT monitor.

 

RESULTS:

 

With the Delay ON, if I invert the B Polarity the Delay disappears. Cancels itself out.

With the Delay OFF, if I invert the B Polarity there's a SLIGHT change in tone - as you say, "thicker" - but nothing you couldn't duplicate easily with EQ.

With the EQ Block OFF there's an overall change to the tone as expected.

With the B Polarity inverted the level of change is equivalent to the change when inverting with the EQ ON.

I'm not hearing the "distorted" Ping Pong delays. Different ears maybe. See conclusions.

 

CONCLUSION:

 

The polarity question is interesting, but not really important. If you want "thicker" tone, use EQ.

I can't explain the distorted delay since I don't hear it, but distortion is usually a result of gain staging problems. Maybe there's a difference between the levels you're getting back from the MVs in the FX Loops vs the WhoWatts I used for the test? 

 

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Well thanks for testing around with my problem with interesting results. I will work a little more on that. For now:

On 9/19/2022 at 7:02 PM, rd2rk said:

The polarity question is interesting, but not really important. If you want "thicker" tone, use EQ.

 

why use EQ when I can switch to "Inverted". Or do you think it should stay on "Normal" and better use EQ? 

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On 9/20/2022 at 7:13 AM, b418me said:

why use EQ when I can switch to "Inverted". Or do you think it should stay on "Normal" and better use EQ? 

 

Exactly. To my ears the difference in tone was minimal. To your ears, you will probably find that having the much more precise control that EQ would afford will give you more options than the ON/OFF nature of the invert method, without unknown and probably unwanted side effects. Also, you may find that placing a Parametric EQ before the delay and sweeping various frequency bands might turn up the cause of the distortion that you hear in the delay.

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On 9/19/2022 at 6:02 PM, rd2rk said:

I had another go at your preset.

 

So did I - following your example of substituting the FX Loops with WhoWatt preamps I went through it again.

 

The results are the same no matter if the split point is a Y Centred or A/B Even Split into the pair of WhoWatts then the Merge Mixer Centre Pan A & B Polarity Normal the audio goes through the PingPong Delay and 2db boost of the stereo Simple EQ block then out through the Left and Right XLRs to my Tannoys. No Problem, unless you hit the B Polarity Footswitch and the result is silence, because just as in a Null Test, the 180 degree inverted phase signal cancels out the other path. This is exactly what I would expect to happen with this setting. Now if you change only the Merge Mixer A/B pan to 100 left and right, you only get a partial cancelation of the audio because the panning means the inversion of the signal is not 180 degrees, which makes the resulting signal sound somewhat weedy and thin.

 

Now, because you had used the PAIR of WhoWatt preamps, I thought that this not going to get us any further if both Preamp blocks are on the default settings. The audio cancels out because the sound waves are identical, therefore I messed around with the Bass, Mid and Treble on each one and then checked. Sure enough, more signal passes through when inverted because the waves are different and they only cancel the same frequencies. 

 

It suddenly struck me that the OP "b418me" says he is using a pair of Vox MV50 AC, that are essentially micro versions of the AC30, therefore swap the WhoWatts for a pair of A30 Fawn Nrm blocks. I guess this would put me as close as possible to the rig brother "b418me" is using. He says is running identical amps into slightly different cabs, (that probably doesn't have much bearing on this), but I seriously doubt both amps are dialled in the same, so the phase cancellation will not be as great. Correct, using the Fawns dialled in differently gets a lot more of the signal through without as much obvious phase cancellation even when the panning is centred, and it is far more noticeable when hard panned. Conclusion is that  "b418me" is suffering from phase cancellation, but it is controllable to a point. Maybe he is more sensitive to it than we are.

 

On 9/20/2022 at 2:13 PM, b418me said:

Well thanks for testing around with my problem with interesting results. I will work a little more on that. For now:

why use EQ when I can switch to "Inverted". Or do you think it should stay on "Normal" and better use EQ? 

 

Hi,

 

As you have already noted, in the Owner's Manual it states: "Typically, this should be set to "Normal". Well, as far as this digital stuff goes there are no real rules, just use what sounds good to you. Having said that - the fact the there are some obvious frequency anomalies happening when the phase of the signal is inverted, I'm with "rd2rk" on this one and would suggest that fixing it with using "Normal' and using the EQ block to iron any issues out.

 

Hope this helps makes sense.

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On 9/20/2022 at 9:23 AM, datacommando said:

The results are the same no matter if the split point is a Y Centred or A/B Even Split into the pair of WhoWatts then the Merge Mixer Centre Pan A & B Polarity Normal the audio goes through the PingPong Delay and 2db boost of the stereo Simple EQ block then out through the Left and Right XLRs to my Tannoys. No Problem, unless you hit the B Polarity Footswitch and the result is silence, because just as in a Null Test, the 180 degree inverted phase signal cancels out the other path.

 

Interesting that you got silence, while I got the expected signal minus the Ping Pong Delay.

 

I ran the test over again to see what the difference might be.

I replaced the WhoWatts with Fawn Nrm for apples to apples.

When my mixer is panned hard L/R invert gives the results I reported previously - expected signal with only the delay canceling out.

When I center the channels on my mixer I don't get silence, but the signal is so weak I have to put my ear to the speaker else the guitar strings drown it out.

The Delay still cancels out.

 

What's it all mean? IDK. The lesson I choose to take from this is that inverting the polarity opens a door to a parallel universe where anything might happen, so I'll just leave it alone until someone explains a real world practical application for using it!

 

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On 9/20/2022 at 5:34 PM, rd2rk said:

What's it all mean? IDK. The lesson I choose to take from this is that inverting the polarity opens a door to a parallel universe where anything might happen, so I'll just leave it alone until someone explains a real world practical application for using it!


I’m gonna blame this guy!

 

 

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