Jump to content

Routing Help: Placing STEREO Effects IN FRONT of DUAL Amp+Cab


bobguido
 Share

Recommended Posts

This is a Question for Line 6 Helix customer support and Helix users
 

Can you run the built-in Helix effects or your external (Strymon etc) effects via the stereo effects loops, IN STEREO BEFORE two seperate amp+cab(or IR) models for a true stereo rig with your effects in front of the amp simulation instead of after the amp and cab simulation?
 

In the Helix manual, it says that if you put stereo effects in front of an amp or cab block that the stereo effect gets summed to mono.
 

With another modeller unit that I use, I can setup two seperate amp and cab blocks, pan one amp+cab 100% left and the other amp+cab 100% right. Then I can place any stereo effects blocks I want in front of those two left and right amp+cab blocks for a true stereo amp rig with all of my effects placed in front of the amp and cab. That's where I like my effects and I like them in stereo.

I originally came from using a completely stereo pedalboard with mostly strymon and boss pedals running all in stereo into two VOX AC30 tube amps so that is the rig that I am trying to maintain the sound of now.

Any help or advice would be greatly appreciated.  The Helix is a beautiful piece of technology Line 6!

 

Link to comment
Share on other sites

You could place your stereo fx (either internal Helix effects, or physical stereo effects units) early in the signal chain and then split the signal path behind them using a Y Stereo Split in Helix.  

 

So your stereo fx are feeding two separate mono paths now.  Then you can place amp blocks on those two separate paths and send those along to separate output blocks.  Then pan the outputs of both output blocks to L and R.

 

Depending on how much routing and DSP you need from Helix you're best be might be to have Path 1a on the top go to an output block (hard panned to one side).  And have path 1b continue on to path 2 on the bottom.  Then have path two's output panned to the other side.

Link to comment
Share on other sites

TL;DR: Yes, Helix can approximate this.

 

So your stereo fx are feeding two separate mono paths now. Then you can place amp blocks on those two separate paths and send those along to separate output blocks.  Then pan the outputs of both output blocks to L and R.

 

All of Helix's paths are stereo, and the Split Block splits both the left and right signals to both A and B.

 

With another modeller unit that I use, I can setup two seperate amp and cab blocks, pan one amp+cab 100% left and the other amp+cab 100% right. Then I can place any stereo effects blocks I want in front of those two left and right amp+cab blocks for a true stereo amp rig with all of my effects placed in front of the amp and cab. That's where I like my effects and I like them in stereo.

 

What's happening in your other modeler is that its split separates the left and right signals to two separate mono feeds into two mono amps, which if their downstream paths are panned hard left and right, will appear stereo. Any stereo effects are indeed summed to mono into the amp, but the path after the split was more than likely mono to begin with. With Helix, it sounds mono because both the left and right signals appear at both paths, and when merged to mono at the amps, don't give the same stereo width as two mono paths—the sonic difference between the amps and cabs give you a bit of separation, but you're right, the effects before them will appear mono.

 

However, you can do what you want in Helix with two additional blocks:

  1. After any stereo effects block but before the Amp block on each path, add a Volume/Pan > Stereo > Pan block.
  2. Pan one Pan block all the way left and the other all the way right. "Pan" is actually a misnomer, as the block actually acts as a stereo balance control; that is, when panned all the way to the left, it'll pass only the left side of, say, a ping pong delay. The reason we don't call that parameter "balance" is because few people know the difference, and "pan" is much more ubiquitous.
  3. Make sure your Merge > Mixer Pan parameters are panned hard left and hard right as well.

We have a wish list item for a new Split > Separate L/R block that would send the left side to Path A and the right side to Path B. Not sure how far down it is tho'. It'd save two block locations, but the DSP savings would be negligible.

 

EDIT: Since this writing, we've added Balance Parameters to the Split > Y block. Panning these hard left and hard right effectively accomplishes the same thing as adding two Pan blocks after the split.

Link to comment
Share on other sites

 

This is a Question for Line 6 Helix customer support and Helix users

 

Can you run the built-in Helix effects or your external (Strymon etc) effects via the stereo effects loops, IN STEREO BEFORE two seperate amp+cab(or IR) models for a true stereo rig with your effects in front of the amp simulation instead of after the amp and cab simulation?

 

In the Helix manual, it says that if you put stereo effects in front of an amp or cab block that the stereo effect gets summed to mono.

 

With another modeller unit that I use, I can setup two seperate amp and cab blocks, pan one amp+cab 100% left and the other amp+cab 100% right. Then I can place any stereo effects blocks I want in front of those two left and right amp+cab blocks for a true stereo amp rig with all of my effects placed in front of the amp and cab. That's where I like my effects and I like them in stereo.

 

I originally came from using a completely stereo pedalboard with mostly strymon and boss pedals running all in stereo into two VOX AC30 tube amps so that is the rig that I am trying to maintain the sound of now.

 

Any help or advice would be greatly appreciated.  The Helix is a beautiful piece of technology Line 6!

 

 

You can do this with the Helix as well. You can split a single stereo path into two paths and feed two separate amps. The only trick is that when you split a path, it actually splits it into two stereo tracks (not two mono tracks as mentioned above). To get two mono paths, you need to insert pan blocks in front of each amp model and pan one hard left and the other hard right. This will give you a true stereo spread so you have the left side going into one amp and the right side going into the other.

Link to comment
Share on other sites

You can do this with the Helix as well. You can split a single stereo path into two paths and feed two separate amps. The only trick is that when you split a path, it actually splits it into two stereo tracks (not two mono tracks as mentioned above). To get two mono paths, you need to insert pan blocks in front of each amp model and pan one hard left and the other hard right. This will give you a true stereo spread so you have the left side going into one amp and the right side going into the other.

 

So much more succinct, amigo. I type way too much.  :P

Link to comment
Share on other sites

TL;DR: Yes, Helix can approximate this.

 

 

All of Helix's paths are stereo, and the Split Block splits both the left and right signals to both A and B.

 

 

Ahhh, I did not realize that.  I appreciate the correction. Sorry for any added confusion

Link to comment
Share on other sites

If I use an IR instead of the built in Cab blocks can my IR run as a DUAL or Stereo Cabinet or do I need to use two IR's?

Can the Helix run two IR's for a true stereo cabinet setup?

 

Helix currently supports mono IRs, but yes, it can run up to four IRs—two per path (DSP permitting).

 

May I suggest that at some point down the line, you revise the Helix so that stereo effects can be placed before and after a stereo amp and cab (IR) setup?

 

Let's take a Ping Pong Delay with echoes that jump from left to right and back every 300ms.

 

If a Split block splits a stereo signal into separate mono Left and mono Right paths (which Helix does NOT do), the Amps will be fed different signals—Amp 1 gets the Left at 300ms, Amp 2 gets the Right at 600ms, Amp 1 gets the Left again at 900ms, Amp 2 gets the right again at 1200ms, and so on. Doesn't matter whether the amps are mono or not (they are), they're passing different signals through at different times. If the two paths are later panned hard left and hard right at the mixer block, the signal bounces between your ears and these differences make the resultant signal sound wide and stereo-like. See diagram A below.

 

But if a Split block splits a stereo signal into two identical stereo Left+Right paths (as Helix does), the Amps are being fed the same signals—Amp 1 and Amp 2 both get the Left at 300ms, the Right at 600ms, the Left at 900ms, and the Right at 1200ms. And because they merge these two duplicated stereo signals to mono (like amp models in all other modelers), the result sounds mono-ish, because they're passing the same signals through. See diagram B below.

 

Adding Pan blocks to each Helix path before the amp forces the paths to pass through different sides of the Ping Pong delay at different times, which makes them sound stereo. See digram C below. Or if we eventually add a Split > Separate L/R block, it'd do the same thing, but wouldn't waste two block locations.

 

EDIT: Since this writing, we've added Balance Parameters to the Split > Y block. Panning these hard left and hard right effectively accomplishes the same thing as adding two Pan blocks after the split.

 

There are good reasons for not making stereo amp models:

  • (Almost) no real guitar amps are true stereo; that is, they don't accept a stereo guitar, process each side separately, and spit them out separate outputs
  • Stereo amp models would take literally twice the DSP; as Helix's Amp+Cab models are the most DSP-intensive category, you might not have enough horsepower to add stereo effects to pass through them anyway!
  • Any true stereo amp model would effectively be just two identical mono amp models with virtual pan blocks before them anyway. So really, by adding those Pan blocks before the two Helix amps, you're effectively creating one big stereo amp model :)

EDIT: Wasn't entirely satisfied with my verbiage, so I drew a picture. Think of the green dashes as Ping Pong Delay echoes; if it's above the line, it's in your left ear, if it's below the line, it's in your right ear, if it's on the line, it's mono.

 

ameoVHl.jpg

  • Upvote 1
  • Downvote 1
Link to comment
Share on other sites

Helix currently supports mono IRs, but yes, it can run up to four IRs—two per path (DSP permitting).

 

 

 

Let's take a Ping Pong Delay with echoes that jump from left to right and back every 300ms.

 

If a Split block splits a stereo signal into separate mono Left and mono Right paths (which Helix does NOT do), the Amps will be fed different signals—Amp 1 gets the Left at 300ms, Amp 2 gets the Right at 600ms, Amp 1 gets the Left again at 900ms, Amp 2 gets the right again at 1200ms, and so on. Doesn't matter whether the amps are mono or not (they are), they're passing different signals through at different times. If the two paths are later panned hard left and hard right at the mixer block, the signal bounces between your ears and these differences make the resultant signal sound wide and stereo-like. See diagram A below.

 

But if a Split block splits a stereo signal into two identical stereo Left+Right paths (as Helix does), the Amps are being fed the same signals—Amp 1 and Amp 2 both get the Left at 300ms, the Right at 600ms, the Left at 900ms, and the Right at 1200ms. And because they merge these two duplicated stereo signals to mono (like amp models in all other modelers), the result sounds mono-ish, because they're passing the same signals through. See diagram B below.

 

Adding Pan blocks to each Helix path before the amp forces the paths to pass through different sides of the Ping Pong delay at different times, which makes them sound stereo. See digram C below. Or if we eventually add a Split > Separate L/R block, it'd do the same thing, but wouldn't waste two block locations.

 

There are good reasons for not making stereo amp models:

  • (Almost) no real guitar amps are true stereo; that is, they don't accept a stereo guitar, process each side separately, and spit them out separate outputs
  • Stereo amp models would take literally twice the DSP; as Helix's Amp+Cab models are the most DSP-intensive category, you might not have enough horsepower to add stereo effects to pass through them anyway!
  • Any true stereo amp model would effectively be just two identical mono amp models with virtual pan blocks before them anyway. So really, by adding those Pan blocks before the two Helix amps, you're effectively creating one big stereo amp model :)

EDIT: Wasn't entirely satisfied with my verbiage, so I drew a picture. Think of the green dashes as Ping Pong Delay echoes; if it's above the line, it's in your left ear, if it's below the line, it's in your right ear, if it's on the line, it's mono.

 

pTpWeKc.jpg

Nice Work, DI! 

But it seems as a PR stunt to say that the Helix way is "more" stereo than what you categorize as "other modellers" - Its the same thing :p 

 

But any way - it is a clear explanation :D Tumbs up :) 

Link to comment
Share on other sites

But it seems as a PR stunt to say that the Helix way is "more" stereo than what you categorize as "other modellers" - Its the same thing :P

 

Hmmm, that wasn't my intention; thanks for the heads up. I'll change that when I get to the office.

 

EDIT: Updated illustration, added two lines where the signal integrity is stereo.

Link to comment
Share on other sites

2.  One amp model you are missing is a neutral preamp.  Many experimental guitarists like the sound of just plugging the guitar straight into a Neve 10 series mic preamp with a DI.  This direct sound involves no amp simulation or cabinet simulation but provides a unique tone with a very wide frequency response for the guitar and once you add effects, you really hear the benefit of going direct because the effects sound huge, being fed from a full frequency guitar signal instead of one limited by the small frequency range of a guitar amplifier speaker.  It's a different and non-traditional guitar tone but it would be a standard option to have for any modeler I do believe.  A preamp block modelled after a Neve 1073 preamp with maybe the 10 band graphic EQ modeled after the very popular and standard studio EQ on guitar in a final mix - the API 560 Graphic Equalizer.

 

 

There actually is a preamp model in the Helix. It's not modeled after a Neve, but it's a nice way to warm a signal up a little. It's under the "Preamp" section of the menu, and under the "Mic" heading. But you don't have to use with a mic. I use it for my acoustic guitar and mandolin patches.

Link to comment
Share on other sites

4.  CPU -  Running a stereo guitar rig in the Helix with for example, a stereo chorus block, two stereo delay blocks and two stereo reverb blocks in front of a stereo amp setup. I don't think something like this should be intensive or impossible. If running out of processing power, while creating this (very standard these days) kind of effects chain, I think the Helix processing resources may have been overlooked. Most guitarists interested in this kind of product are looking to setup complex stereo rigs with lots of effects to downsize the footprint of their live and studio pedalboard + amp setup. I love the looping being built in but for me, I would like to run lots of effects plus the looping machine with a stereo amp setup with the effects in front of the amp and I am sure that many other guitarists would like to run similar and even more complex setups.

 

Note that each of Helix's two paths gets its own DSP. If you attempt to build everything on Path 1, you're only using half the available horsepower. Check out the 8 TEMPLATES > 01B Parallel Spans preset as an example of how both paths can be utilized to make one huge parallel dual amp tone. Also, page 19 in the Helix Owner's Manual provides a few tips and tricks for getting the most out of your DSP.

Link to comment
Share on other sites

I know now that I need at least two paths to achieve a stereo amp+cab setup with effects running in front of them.

 

Correct; you'd have to do that in the real world with real amps too. The only way to hear stereo effects through 99% of amps is to... have two amps.  :) In the studio, stereo effects are typically added after the amps, but yeah, they sound very different. Effects before amps tends to shave off their squirrelly bits in a pleasing way.

 

With Helix, I am able to replace everything except for my Strymon Big Sky and my Boss RV3. Oh, and once in a while, I need to pull out my Line 6 DL4 for the Auto Volume Echo effect that nothing else can do quite like the DL4. I would love to be able to replace everything with the Helix and not have to use any other gear. What a dream that would be. I am getting closer than ever before though.

 

I have Helix Rack/Control, Helix floor (at work), POD HD Pro, and M9. I still play through my DL4 all the time, mainly because it's so easy to make killer weird ambient noises with the expression pedal:

  1. Connect an expression pedal to DL4.
  2. Move the expression pedal to the heel down position and move any or all of the knobs.
  3. Move the expression pedal to the toe down position and move any or all of the knobs. Now moving the expression will morph all knobs. Instant weird tape echo madness. I've made entire ambient pieces with only a DL4.

Why everyone and their mom isn't using expression with their DL4 is beyond me. It's killer fun.

Link to comment
Share on other sites

  • 1 year later...

Or if we eventually add a Split > Separate L/R block, it'd do the same thing, but wouldn't waste two block locations.

 

 

Is the currently available Split Y actually doing this if you setup Balance A 100L and Balance B 100R on the Split controls? If so, I guess that Pan Blocks are not requested anymore to achieve stereo.

Link to comment
Share on other sites

Is the currently available Split Y actually doing this if you setup Balance A 100L and Balance B 100R on the Split controls? If so, I guess that Pan Blocks are not requested anymore to achieve stereo.

Good eye. We were going to add a new Split block type and then realized it's way easier to just add those parameters to the default Split block.

  • Upvote 1
Link to comment
Share on other sites

However, you can do what you want in Helix with two additional blocks:

  1. After any stereo effects block but before the Amp block on each path, add a Volume/Pan > Stereo > Pan block.
  2. Pan one Pan block all the way left and the other all the way right. "Pan" is actually a misnomer, as the block actually acts as a stereo balance control; that is, when panned all the way to the left, it'll pass only the left side of, say, a ping pong delay. The reason we don't call that parameter "balance" is because few people know the difference, and "pan" is much more ubiquitous.
  3. Make sure your Merge > Mixer Pan parameters are panned hard left and hard right as well.

We have a wish list item for a new Split > Separate L/R block that would send the left side to Path A and the right side to Path B. Not sure how far down it is tho'. It'd save two block locations, but the DSP savings would be negligible.

 

I run all of my effects into the front of two amps in the helix as well. I'm just using the controls on the split block itself to hard pan, same on the merge block. I recorded a few reverbs yesterday with this preset and they sound stereo to me, particularly when I switch to the boss RV6 (0:28) the stereo image is extra obvious. Am I doing something wrong? I don't really understand the difference between what I'm doing and what you recommended. I'd really appreciate if you could take a look at my split/merge block settings. 

Recording:  https://www.dropbox.com/s/kw64819m7ost4ss/2017-04-29%20Helix%20RV6%20Polara%20Reverbs%20Demo.m4a

Preset: https://www.dropbox.com/s/w87wdy4o73bo9uo/AC30%20Dual%20Amps.hlx

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...