I like distortion — most guitar players do, right? And the sound of distorting each string individually with hex distortion is also pretty cool. But I always found standard distortion a bit too dirty and hex distortion a bit too clean. So in the mid-’80s, I created the Quadrafuzz multiband distortion processor, which split the guitar into four bands and distorted each one individually. This reduced the intermodulation distortion associated with standard distortion to produce a far more “focused” sound, yet it still retained a dirtier, more “rock and roll” sound than hex distortion. (It has since been virtualized by both Steinberg and MOTU and offered as a DIY kit by PAiA Electronics.)
When the Line 6 Helix appeared, its four independent processing paths provided a fantastic platform for creating multiband effects — and when the Native version appeared as a plug-in, I was in multiband heaven.
That’s the good news. The bad news is that coming up with really good multiband presets is a challenge. First, the Helix doesn’t have a dedicated crossover module or multiband dynamics processor that could split the guitar easily into four separate bands. Second, with four bands there are so many parameter adjustments and variables that tweaking the settings can take forever. Third, amps and cabs require a lot of CPU: put four of them in a preset, and there’s not a lot of CPU left over for anything else.
Fortunately, it’s possible to gain many of the benefits of multiband processing simply by splitting the guitar into two bands — and the Helix makes it incredibly easy to do that. Furthermore, because you need only two amps and cabs, there’s lots of CPU left over for other goodies.
Before continuing, note that multiband distortion is an alternative to conventional distortion, and single-band distortion still has its merits. However, what’s even better than either one by itself is being able to choose the type of distortion that fits your music like a glove.
Split the Difference
Figure 1 shows the layout for a basic multiband processing setup. You can run two parallel paths in a mono in/stereo out or stereo in/stereo out configuration (upper image in fig. 1), or two independent stereo paths (lower image in figure 1). When using Helix Native to do independent stereo channels, remember to set both channel inputs to Host so that the guitar track goes through both paths.
Figure 1: Block diagram for 2-band Helix processing, based on splitting the signal through two EQs, showing mono processing in the upper half and stereo processing in the lower half.
A Low and High Cut EQ precedes each Amp+Cab block. We’ll cover the Volume blocks later, because they’re more about preset development and diagnostics.
The Low and High Cut EQ is perfect for creating a 2-band crossover. I tested this by feeding white noise into the Helix with only a Low and High Cut EQ block in each path. The goal was to have a flat response whether the Helix was bypassed or split into two paths, each with its own filter (see fig. 2).
You can also use the Split’s Crossover function when working with a single path, but there may be times when you want the Low and High Cut frequencies to overlap so they emphasize a specific frequency, and besides, you can’t use the crossover across the two independent paths.
Figure 2: Teaming the Low and High Cut filters creates a crossover between high and low frequencies.
The top image shows the white noise’s frequency response with the Helix bypassed. The second image down shows the response for the audio path with the high cut, and the image below, the path with the low cut. Summing them together gives the response in the bottom image — which is essentially the same as the Helix being bypassed.
Figure 3 shows the settings for the Low Cut and High Cut EQs. It couldn’t get any simpler — for the low-frequency path, move the High Cut slider all the way to the left (1kHz). For the high-frequency path, move the Low Cut slider all the way to the right (1kHz). Increase each filter’s level by +5dB to compensate for signal loss going through each path, due to the filtering action.
Figure 3: Adjusting only a single filter parameter on each of the two EQ blocks (outlined in green) creates a frequency split.
Plus More!
Multiband distortion not only gives a more articulated sound with heavy distortion, but as intimated before with the reverb, we can process the two splits separately. This means you can tweak the amp and cab for each path optimally for the high and low frequencies. It helps to be able to solo each path as you tweak; although the Helix doesn’t have a solo button per se, it’s easy to create a mute button to silence the path we don’t want to hear.
To do this, insert a Volume/Pan block (fig. 4) and set the Gain parameter to minimum (-120.0dB). When you enable the Gain block, because the volume is the minimum possible, it becomes a mute block. (What’s more, if you’re into snapshots, you can assign the Gain parameter to snapshot control and adjust the blend of the two channels easily — but getting fully into snapshots is beyond the scope of this article, so let’s proceed to tweaking the split.)
Figure 4: It’s easy to turn a Gain block (outlined in light blue) into a mute button.
Now for what I feel is an enhancement. If you listen carefully to audio example 2, note there’s some high-frequency buzziness (which you may or may not like — but personally I’m not a fan of it). This is because the split isolates the highs, making the fizzy sound more apparent. However, isolating the highs also makes it easy to address this issue.
Referring to figure 5, I’ve pulled back the High Cut on the cabinet to get rid of the buzziness. And why not? A traditional, physical guitar cab rarely goes much over 5kHz, unless it has a high-frequency speaker of some kind. However, this makes the sound seem subjectively a bit duller than if you keep the highs. So you can add a Simple EQ and boost the High Gain parameter a bit.
Figure 5: Being able to tweak cab settings independently for the high and low frequencies is a big deal. Here, the cab’s high cut combined with a post-cab high-frequency boost (the blocks are outlined in orange at the top, with the relevant parameters outlined in light blue) reduces buzziness yet retains brightness.
Often +1.0dB of High Gain is enough, but if you want some brightness that goes beyond the original sound, you can always increase this a bit (in the audio example, there’s a +2.1dB boost). Pulling the cab High Cut down further cuts down even more of the buzz, but you’ll need to increase the EQ’s High Gain parameter to compensate — and there’s definitely a point of diminishing returns. I also trimmed the cab response on the low-frequency split, tweaked the drive a little bit, and reduced sag for both amps to give a more dynamic effect.
This just scratches the surface of the flexibility that splitting the sound provides. You can use different mics on the two cabs, choose different Amp+Cab blocks for the two paths, apply the Dual Delay module for faux stereo effects, and much more.
Finally, a Note About CPU Consumption
Each path has its own CPU limit, so it’s preferable to use a setup with two independent paths, compared with a single path with parallel effects. Even though the EQ modules required to do the splitting draw very little CPU, you’ll be able to add more modules overall with two independent paths.
That’s enough for now, but I hope you find this technique as useful as I have. Granted, moving to 3-band and 4-band presets takes this concept even further — but for good sounds, fast, without going down a rabbit hole of tweaking, check out the virtues of doubling down on your Helix tone.
To find out more about Helix pedals, give your Sweetwater Sales Engineer a call at (800) 222-4700.
