When it comes to playing with pedals, few things are handier than an expression pedal for real-time parameter adjustments, especially if your hands are normally occupied by playing a guitar, keyboard, or another instrument. But believe it or not, foot-based treadles aren't the only way you can control your effects, and I'm not just talking about switching over to MIDI-capable pedals. In fact, there's a number of alternative options for automating expression, ranging from other pedals to standalone sequencers, and much more.
Indeed, there's a number of great tools out there for opening up your pedals to be controlled by synthesizers, sequencers, and more! In this article, we'll show off several of our favorite devices, and share some audio and video examples that demonstrate how these can be used with pedals.
A while back, we shared an article on using control voltage with effects pedals, and that article serves as an excellent starting point to thinking about how to extend your usage of expression pedal inputs. I'd recommend starting there if you're curious to know more about how expression pedals work and understand why certain precautions are necessary to keep your pedals safe from damage.
Simple Alternate Forms of Expression Pedals
When most people think of expression pedals, the first thing to come to mind is a foot controller that resembles a wah or volume pedal. And this certainly remains the most common type of expression pedal, but it's not the only kind out there.
For compact, hands-on control, it's hard to beat the Expression Slider from Old Blood Noise Endeavors. Rather than using a rotary potentiometer connected to a pulley system inside of a foot pedal, this tiny friend simply sports a slide pot, allowing for a much smaller form factor. In noise scenes and other styles of music where direct pedal manipulation is warranted, we've definitely seen pedal boards stacked up with several of these Sliders for control of several effects simultaneously.
Maybe you don't need the full sweepable range of an expression pedal all the time, and would rather toggle between two different values. In that case, Electro-Harmonix has just the thing: Cntl Knob is a very small, static expression pedal that switches back and forth between the values specified on its two Exp knobs. How might one put this simple pedal to use? My immediate thought would be to pair this with a delay pedal where the time of the delay repeats is open to expression control. By using one value of the Cntl Knob to be your base rate, the other could be tuned to be twice as fast or slow, and with high feedback settings this will result in fun, octave pitch-shifting. You can hear this idea put into practice in the adjacent audio example, where I used this with the Delay Llama Xtreme from JAM Pedals. But there's countless other applications for abruptly shifting between two static expression values, and could lead to some interesting performance opportunities.
Of course, if traditional expression pedals still seem like the best approach for you, it's worth knowing that EHX also makes a Dual Expression Pedal. Exactly as the name suggests, this offers two separate channels of expression in one unit, with the option to scale and reverse them individually.
Sometimes, a performance might be so intensive that you need external help modulating expression parameters. Likewise, you may crave incredibly precise values, precise repeatability, or some shape of movement which is impossible for humans to achieve. In these situations, you'd need to turn to something which can generate fluctuating or sequenced voltages for you, and there just so happens to be a few available in a pedal-like format, once again from our friends OBNE and EHX.
Expression Ramper is a similar concept to the Cntl Knob, with the main difference being that it can automatically switch between the two values. With a central Rate control, players may glide between states with a tap of the footswitch, or engage the triangle or square waves to continuously modulate your expression-capable pedals. This is a great way to add synth-like LFOs to any basic pedal with an expression input, or expand a more-adventurous pedal that already has built-in modulation, like Strymon's NightSky.
If two stored expression values aren't enough for you, try eight! The EHX 8 Step Program is an eight-stage sequencer, boasting presets, tap tempo, glide, and a host of other features. Back in the day, Electro-Harmonix offered a straightforward, eight-step analog sequencer that was a compact, affordable way to control synthesizers, but today it can be used as an expression sequencer too!
One of the more interesting applications for sequencing expression would be in controlling pitch effects, like the EHX Pitchfork Plus or even the Meris Hedra. With some attention to musical composition and clever tuning of the eight stages, it's easily possible to add flowing counterpoint to any monophonic part. For the audio example below, I carefully tuned a sequence on the 8 Step Program to control the amount of pitch shift on the Pitch Fork, and then wrote brief guitar lines that would harmonically complement the intervals being generated.
With the following sections of the article, we're starting to venture into more general territories with control voltages, so be sure to proceed with caution and use floating ring cables where necessary.
If you've ever been inspired by the Roland D-Beam, then Sunobuono's LAZER is for you. Though it seems functionally similar to a theremin, LAZER is based around an infrared sensor, using just a single axis of proximity detection compared to the two antennae found on a theremin. And thanks to its CV output, it can be patched into a number of different instruments and effects! Similar to the LAZER is Koma's Kommander, which operates on the same principle, but contains two IR sensors in one box. Each channel has its own outputs, so they may be patched independently, though of course by sharing an enclosure, it's highly possible (and intentional) that you may have optical crosstalk between the channels.
But if you prefer to physically touch your controllers, there are plenty of options for that too. On the more straightforward side of things, Low Gain Electronics has their Variable Force Generator, which through the use of force-sensitive resistors can provide four channels of voltages. If you're looking for something more atypical, Expressive E's Touché is a favorite for gestural control. This wibbly, wobbly wooden friend can spit out a number of different signals based upon the direction it's moving.
Generate Expression with Gestures
Unlocking Expression Inputs with Synthesizers
With such free usage of pure voltages to control pedals, it only makes sense to mention some synthesizers that could be a ton of fun to use. We touched upon the specifics of using modular synthesizer control voltages for expression in a previous article, so we're going to focus more on some creative applications of standalone synthesizers controlling pedals.
There's a number of synthesizers out there with CV outputs, ranging from keyboard synths to drum machines and semi-modular pieces. Personally, I'm a huge fan of Elektron's Analog Four, and while it's obviously a highly capable analog synthesizer, it also provides four channels of control voltage outputs, each under the control of Elektron's powerful sequencing workflow. This is especially fun to use with pedals, because if you want to process the sound of the A4 with something other than its internal chorus, delay, and reverb effects, you're already equipped with a way to make it highly dynamic and responsive.
Another one of my favorite, flexible synthesizers with CV outputs is the ASM Hydrasynth. Among the many things that these cool instruments can do, the CV outputs are fully accessible to routing within the Mod Matrix, making it possible to output control signals from LFOs, envelope generators, aftertouch, and more. One thing I particularly enjoy doing is enabling Step Mode for an LFO, and using it to generate precise step sequences that can be patched out to other instruments, or even pedals! In fact, that's exactly what I'm doing in the video example below, where I'm running the Hydrasynth through Red Panda's Tensor for sequenced loop mangling. Before filming, I configured the Tensor's Time knob to be under expression control, allowing me to capture loops of arpeggios that are then time-stretched and rearranged by the Step LFO.
Inspired by Eurorack: Sequencers and Envelope Followers
But of course, standalone sequencers are a thing too, and while they're typically used with Eurorack systems, they can be just as useful for patching into pedals. It's hard to beat the value of the Korg SQ-1, with its number of different playback modes and support for control voltage and MIDI sequencing. Another one of our favorites is the Make Noise 0-CTRL, which extends standard sequencer behaviors with timing adjustments, pressure control, and extensive patchability. One of the neat things about the 0-CTRL is that the sequencer clock may be turned off, thus stages are manually addressed by the touch pads. With eight steps across three independent channels, it then becomes possible to treat the 0-CTRL as a sort of effects preset manager, recalling expression values for connected pedals upon instantly pressing a pad.
In the video below, I've routed the Hydrasynth through the Meris Ottobit Jr., Red Panda's Raster 2, and Dark World from Chase Bliss. I'm controlling each pedal's expression inputs via floating ring cables connected to each of the sequencer channel outputs on the 0-CTRL, allowing me variable control over the filter cutoff, delay time, and reverb dwell parameters on all of the above pedals, respectively. As I'm playing, I'm able to tap on pads to change sounds, but if I wanted to (and I do in the video), I can patch the Hydrasynth's Clock output into the 0-CTRL clock input to sequence through the defined parameter values.
Some of the most dynamic effects out there make use of something called an envelope follower. Typically found within envelope filters and auto-wah pedals, envelope followers track the dynamics of your playing, and when applied to any effect can lead to an incredible number of interactive sounds. Envelope followers have started popping up in other effects too, but how would you add one to a pedal that doesn't already have it? Of course, one route would be to dive into Eurorack synthesizers, but although it's totally possible to build a small, pedalboard-sized modular synth purely for control purposes, it's still overkill for most situations. Worry not, for there are other options in the form of pedals.
For a more traditional approach, the Mu-Tron Micro-Tron IV serves as an incredibly straightforward envelope follower, in addition to its sculptable envelope filtering capabilities. So long as you have a cable or adapter to transfer the 3.5mm CV output to the more standard 1/4" size that's typically used for expression pedals, you've got a handy way to add dynamic control to nearly any effect. Of course, if you don't want the sound of the Micro-Tron IV to be heard, you'll need to rig up an ABY switcher or something similar, as bypassing the pedal will also disengage the envelope follower.
In the adjacent audio clip, I'm using the Micro-Tron envelope to control various parameters on the Chase Bliss Warped Vinyl, first resulting in a lo-fi, tape-stop sound for my guitar, then dynamic chorusing with a Teenage Engineering Pocket Operator. In the second example, after a few bars of the dry signal, listen closely to when the effect first comes in without the envelope follower. Especially listening to the kick drum, the definition of the transient becomes a bit smeared and tightness is lost. But once the Micro-Tron's envelope follower is engaged just a bit later, the automated sweep of the chorus rate leads to a more coherent use of the effect, thickening the beat in a nice way without sacrificing any rhythmic drive.
If you're looking for an option with more bells and whistles, Second Sound's UniSyn not only contains an envelope follower, but also a preamp, pitch-to-CV conversion, an internal synth voice, and more! This is a great option for anyone hoping to control not only other pedals, but synthesizers and other electronic instruments with their favorite acoustic or electric instrument. You can also find envelope followers as part of expansive virtual modular pedals like the Empress Zoia and Poly Effects Beebo. In this context, the envelope followers may control other modules internally, or routed to hardware outputs for external control of other devices.
If this article is any indication, the traditional foot-controlled expression pedal isn't the be-all, end-all method of controlling your effects. With some creativity, new worlds of effects manipulation are in easy reach, and can put a whole new spin on your sounds. While modular synthesizers certainly reign as the champion of complex, dynamic effects processing, some of the tips and products shared here should set you on a path to crafting your own wild effects processing chains.