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Helix & PC 112 Plus: How best to control master volume?

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Hi Folks. Been a Helix LT user for a number of years, never totally happy when using it with a QSC K10, so I got a PC 112 plus last week. I'm exploring it, but one question I have is how does one control the overall stage volume? I usually run my K10 gain at 100% and then use the LT volume knob to control overall volume - practice vs. stage. But I read elsewhere that I should basically reverse my approach by putting the Helix volume at 100% and using the PC+ knob to adjust overall volume. However, I know that adjusting the input gain feeding into the PC is important (yellow lights up sometimes, preferably not much red at all). My question is how does one add a boost (or an overall adjustment) from the Helix side? In the past I've had the expression pedal control each preset's output block gain b/w 0 db and 7 dB, which worked great as a general volume adjustment tool. But that means I go into the red during solos (say). I hope that's not too confused. Looking forward to your advice!

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Best to provide a max and consistent signal to Powercab, and adjust the overall volume at the Powercab. That is, push tone, pull volume: use drive and master volume controls to set the amount and type of distortion, use channel volume to provide block unity gain and normalize levels across patches, run Helix into Powercab at full volume, and control the overall volume at the very end of the signal chain using Powercab volume.

 

To achieve a boost, its best set the normal output at -3dB, and when you turn on the boost, set the output to 0dB. This ensures a boost will never drive anything downstream into clipping.

 

General rule is to cut what you don't want rather than boost what you do want to preserve headroom.

 

 

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1 hour ago, amsdenj said:

use drive and master volume controls to set the amount and type of distortion, use channel volume to provide block unity gain and normalize levels across patches

 

Thanks very much for your comment! Question: I'm not sure what you mean by "provide block unity gain" - would you please explain a bit more? Also, I'll often find a model that is significantly louder or quieter than others. The Fenders are the latter, IIRC. How do you adapt those? Do you up the output block's gain? Thanks again.

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To avoid gain buildup, and any potential for digital clipping, I generally make sure any block I add is "unity gain". That means I set the level of the block so the overall level doesn't change much with the block on or off. This also helps level your patches, and ensures that each block is getting an input in its sweet spot - the input level it was designed to accept. Hopefully the 2.9 level meters will help with this. But you can use your ears to get pretty close, or a level meeter in your computer, or even a dB meter in your phone.

 

 

 

 

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Amsdenj's recommendations are critical to get good gain staging in your LT.  That is critical for getting good sound to whatever you are using whether it be front of house, K10's, or the Powercab.

 

One of the things I love about the powercab + is that it has an LED to indicate the input levels, and flashes RED when its starting to clip.  So as you build your patch, set your LT to unity gain (no blocks turned on) and adjust the input to your powercab so that it's flashing on your loudest strums in the yellow.  Some might say it could flash briefly in the red, but I adjust the input on the powercab until I get a flash of red, and then back it off a little.   Then you add your preamp/amp/cab/ blocks and watch that LED as you build the patch.  That has saved me lots of efforts in leveling my patches for live play even if gigging without my powercab.  Always check as you add distortion/overdrive blocks, or any block that has a level or gain settting.   The powercab is brilliant!

 

Gain staging is something that most folks overlook.   When using someone else's patches. The first thing you should do is follow the procedure I outlined above and get the amp sim to unity gain followed by all of the other blocks.   Oh and if you are going to add a "boost" to your patch, make sure it doesn't drive your powercab into distortion.  That might entail setting everything else lower to start with.

 

Hope you have great success.

 

Bob

 

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On 3/20/2020 at 4:12 PM, bobcoss said:

Amsdenj's recommendations are critical to get good gain staging in your LT.  That is critical for getting good sound to whatever you are using whether it be front of house, K10's, or the Powercab.

 

One of the things I love about the powercab + is that it has an LED to indicate the input levels, and flashes RED when its starting to clip.  So as you build your patch, set your LT to unity gain (no blocks turned on) and adjust the input to your powercab so that it's flashing on your loudest strums in the yellow.  Some might say it could flash briefly in the red, but I adjust the input on the powercab until I get a flash of red, and then back it off a little.   Then you add your preamp/amp/cab/ blocks and watch that LED as you build the patch.  That has saved me lots of efforts in leveling my patches for live play even if gigging without my powercab.  Always check as you add distortion/overdrive blocks, or any block that has a level or gain settting.   The powercab is brilliant!

 

Gain staging is something that most folks overlook.   When using someone else's patches. The first thing you should do is follow the procedure I outlined above and get the amp sim to unity gain followed by all of the other blocks.   Oh and if you are going to add a "boost" to your patch, make sure it doesn't drive your powercab into distortion.  That might entail setting everything else lower to start with.

 

Hope you have great success.

 

Bob

 

Heya Bob, what do you mean set the Lt to unity gain? And how do you do that?

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Unity gain is the output is at the same level as the input. That will be the case for a Helix patch that has no blocks, assuming the output block level is set at 0dB. 

 

Now as you add blocks to the patch, they may add or remove gain depending on the block. To gain stage a block to unity gain, adjust the block to get the tone you want, then use the block's Level control to make the overall volume the same with the block on or off. This doesn't need to be exact, just close.

 

If you do this, you will 1) provide consistent inputs into downstream blocks, 2) avoid any possibility of digital clipping, 3) drive blocks with the levels they were designed for, and 4) have consistent output to your Powercab, FRFR or direct FOH from patch to patch.

 

 

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On 3/29/2020 at 2:42 PM, amsdenj said:

Unity gain is the output is at the same level as the input. That will be the case for a Helix patch that has no blocks, assuming the output block level is set at 0dB. 

 

Now as you add blocks to the patch, they may add or remove gain depending on the block. To gain stage a block to unity gain, adjust the block to get the tone you want, then use the block's Level control to make the overall volume the same with the block on or off. This doesn't need to be exact, just close.

 

If you do this, you will 1) provide consistent inputs into downstream blocks, 2) avoid any possibility of digital clipping, 3) drive blocks with the levels they were designed for, and 4) have consistent output to your Powercab, FRFR or direct FOH from patch to patch.

 

 

 

Heya, thanks so much for the reply, I kind of get you but not fully. I just recently got the Helix lt and Powercab 112plus together so have no pre built patches.

 

Would you mind taking me through a step by step guide from starting from scratch whenever you have the chance? There's no info on thus stuff in the manuals of both at all and being an ocd head wanna make sure I have everythign right from the start!

 

I havnt changed values on anything from default except 1/4 output to line level and am currently using the big volume knob up full.

I'm also not very good with technical terms!

 

You really seem to knwo your stuff from reading posts around here so help would be so much appreciated,

 

Tom

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On 3/16/2020 at 9:02 PM, amsdenj said:

To achieve a boost, its best set the normal output at -3dB, and when you turn on the boost, set the output to 0dB. This ensures a boost will never drive anything downstream into clipping.

 

OK, a question on this. First, by "normal output" do you mean the preset's output block? (That's the one I used to use to control my master volume, via my expression pedal from 0 to +7dB. Basically I prefer a control range rather than a single boost footswitch.) Second, if I set my input to the PC+ at -3dB so that the signal LED is green with a little yellow, then won't the 0dB push it into the red? I guess there's a balance there... Thanks!

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So 0 to +7dB is what I'm suggesting you avoid. Rather gain stage for unity gain though out your signal chain, ensuring your loudest patch is not clipping Powercab input. Then go to the output block and set a controller to min -3dB, max 0. Set your stage volume and FOH volume with the output set to -3dB (boost off). Then when you boost to 0dB, you're back where you started from with your gain staged signal path, no chance for digital clipping, and you're 3dB louder. Same outcome, but less chance of clipping anything. Of course FOH will need to gain stage similarly.

 

I think of it as "push tone, pull volume". That is, all you're up front patch parameters should focus on getting the tone you want to deliver to the final output stages. Then you get the venue volume by turning up the power amps at the end of the signal chain instead of turning up volumes in the front or middle of the chain as these consume headroom. Want the PA louder, you turn up the master first, not all the faders. Turning up the faders can clip the master bus, turning up the master fader can't. 

 

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Much obliged, @amsdenj. That's what I was thinking. I guess I set the PC+ input with the Helix at -3dB so that the PC+ LED is green with a little yellow flashing, and then trust that the increase to 0dB will not be red? Or is it vice versa (set PC+ input level for 0dB)? I'm also going to post a question about using MIDI to control the PC+ master, as another possible option...

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Hi @bobcoss

 

Where are you making this adjustment , on the input gain on the Powercab ? 

 

“One of the things I love about the powercab + is that it has an LED to indicate the input levels, and flashes RED when its starting to clip.  So as you build your patch, set your LT to unity gain (no blocks turned on) and adjust the input to your powercab so that it's flashing on your loudest strums in the yellow.  Some might say it could flash briefly in the red, but I adjust the input on the powercab until I get a flash of red, and then back it off a little.”

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Sorry.  I just saw your question.

 

Sometimes I make the adjustment on the PC+, but that is only if the helix, or other modeler doesn't have enough output.

 

The LT does have a lot of headroom, so you can adjust the level in the output section until it starts to flash red and back it off.   Since I saw this thread, I saw Jason Sadites created a video to address this.     In another video he addressed how to do the gainstaging properly also.

 

 

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