Source Audio: Hot Hand Midi-Exp

Source Audio's Hot Hand Phaser/Flanger— which was introduced in the August ’07 GP— features a ring worn on the player’s picking hand that controls the stompbox’s parameters.
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Source Audio's Hot Hand Phaser/Flanger— which was introduced in the August ’07 GP— features a ring worn on the player’s picking hand that controls the stompbox’s parameters. The ring sends expression-pedalstyle control voltages via a wireless signal. Though a system requiring the use of a limb already involved in playing the guitar might, at first, appear counter-intuitive, I’ve found that using subtle hand gestures to create tonal variations is more relaxed and freeing than being tied to a foot controller, such as a wah or expression pedal.

As good as the Source Audio effects sound, my first thought after integrating gentle and wild gestures into my arsenal of audio-creation tools was, “Wouldn’t it be great to control other manufacturers’ effects— and even plug-ins—the same way?” Source Audio was already investigating this concept (great minds…, etc.), and a few short years after introducing guitarists to the idea of using their right hands for more than strumming, picking, tapping, and, well, other things, they are introducing the Hot Hand MIDI-EXP (price TBA). This unit will allow pickers to control almost anything that accepts MIDI input or control voltage with the wave of a finger. The MIDI-EXP is still in Beta testing, but I got a sneak peak at this radical piece of gear.

The MIDI-EXP pedal comes housed in the same lightweight, solid casing as Source Audio’s Soundblox pedals. Though far from a MIDI expert, I found it surprisingly easy to leap right in and begin employing some of the features that had stirred my initial excitement. I plugged the ring sensor and a MIDI cable into their appropriate receptacles, and then ran the MIDI cable from the EXP’s output to my M-Audio Firewire 1814’s MIDI input. Firing up Ableton Live, I ran my guitar into one of its Session channels, and set it to recognize MIDI input from the 1814. In the channel’s plug-in chain, I added Live’s Auto Filter to Native Instruments Guitar Rig 3 amp simulator.

MIDI-EXP’s center knob works three ways: You can turn it to increase and decrease parameter values (which are shown on a large, bright LED display), you can push it down and release it to jump from Message Bank controls to Utility Bank controls, and you can hold it down while turning it to choose controls within the banks. It defaults to the Continuous Controller setting—which was all I needed to quickly become “Lord of the Ring.”

Luckily, Ableton makes it super easy to set up MIDI control of plug-ins in Live. I just clicked Live’s MIDI learn button, chose the Frequency parameter on the Auto Filter by clicking on it, and waved my hand. As if by magic, I was now controlling the frequency of the Filter with the ring. MIDI-EXP offers separate control of the X and Y axis—that is, you can control one parameter by moving the ring up and down, and another by moving it back and forth. So by assigning the Frequency to the X axis, and Resonance to the Y axis, I was able to achieve a wide range of subtle and extreme tonal effects with various ring movements. But that’s just the beginning. I assigned the filter frequency to X, and the wet/dry blend of Live’s reverb plug-in to Y to control two effects simultaneously. As Live lets you program multiple MIDI messages, using it with the MIDI-EXP opens up the possibility of controlling dozens of parameters and effects by just moving your finger up, down, or sideways. In addition, I also could manipulate some of Guitar Rig’s parameters, such Studio Delay’s wet/dry blend, or Tremolo rate.

Should I feel self-conscious about waving my hand like a testifying church lady, the MIDIEXP’s Depth control lets me reign in the distance I have to move my finger to manipulate an effect. An Invert button switches the direction of the effect, which, in the case of the filter, allowed me to choose whether moving my hand up increased or decreased the treble.There’s still more. Ramp/Trigger mode lets you start an automatic parameter change by moving your hand past a set point. In Ramp mode, the ring acts more like a switch, and one of my favorite things to do with this mode is set it so that when I move my hand across a particular point in space, it causes the feedback of my TAL-Dub delay plug-in to gradually increase to infinite for cool “runaway” effects. Waving my hand in the same direction across the same point sets the feedback gradually ramping back down to a predetermined level. You can control the start and stop points, as well as the speed of the ramp up, and this approach sounds way more musical than instantly jumping between infinite feedback and none.

All this, and I still haven’t discussed the MIDI-EXP’s Expression function. Source Audio’s other Hot Hand pedals have an Expression out jack that allows you to command the parameters of more than one Hot Hand pedal with a single ring, as well as control other manufacturer’s devices that permit voltage controlled expression pedals—like Line 6’s DL-4 delay, or IK Multimedia’s StompIO. By plugging one end of a 1/4" TRS cable into the MIDIEXP’s Expression output, and the other into an Electro-Harmonix Holy Stain’s expressionpedal input, I could control the pitch-shift function like a Theremin player, or speed up and slow down the tremolo rate at will. The DL-4’s design made it a little trickier, requiring that I power it up with the Source Audio unit already connected, but it then let me use finger wizardry to control wet/dry mix, feedback amount, or delay length.[Note: Source Audio states that the MIDI-EXP’s Expression output is designed to work with most expression-pedal inputs, but cautions that this function is not standardized, and users should check the manuals for third-party devices to understand what is expected at the expression input.]

Source Audio’s Hot Hand MIDI-EXP expands tremendously on the promise of its Hot Hand pedals, offering digital control (as in fingers) of both analog and digital (as in ones and zeros) effects, DAWs, plug-ins, synths (both hardware and software), and anything else than can be manipulated by control voltage or MIDI. Space, time, and the current limits of my MIDI knowledge permitted me to merely scratch the surface of what a creative guitarist can do with this new product. For example, I haven’t yet figured out what to do with the MIDI Note On/Note Off messages the MIDI-EXP can send, but trust me—I will. The beta preview unit I checked out was largely bug-free, and production models should be available soon. As with any new performance idea, it will take some time to master, but if you want to add some visual and expressive zip to your Moogerfooger, laptop rig, or multieffects pedal, you owe it to yourself to check out the MIDI-EXP as soon as it hits the streets.