Modulation Staging


I think the next "big thing" in effects might be modulation stacking. At first it sounds crazy to have, say, a flanger and chorus going into each other because the overall result will probably be a big, seasickness-inducing mess. But the technique offers a way to create complex effects that can be quite subtle.

We've all heard about gain staging; in guitar rig terms, it usually refers to the practice of passing your signal through multiple separate preamp stages, often in the form of several boost, overdrive or distortion pedals in front of the preamp in your amplifier.

These can give complexity to the overall tone and can allow for very specific shaping of the harmonic spectrum that results. Here's a that PedalShow episode all about gain staging:

Recently people have been talking more about the old practice of reverb staging. Typically this involves using two reverb units. The first provides a short, characterful reverb -- sometimes from an analogue spring. The second provides a longer, background wash that's heard after the first stage dies away. Here's a good video about that:

My interest in modulation stacking was sparked by the recent rash of Leslie speaker simulators in pedal form, because a leslie speaker's sound involves tremolo, chorus and phasing all happening at once, What's more, they can be happening at different speeds depending on how you set the motors in the speaker. For me, it all started with Greg Koch's advocacy of the Neo Instruments Ventilator:

Strymon, EHX and Hammond also make Leslie simulators. Pigtronix has just come out with one that for my money sounds the best of them all and has gone straight onto my want-list:

The Leslie effects give us a clue to stacking several modulation effects. First, you're often hearing modulations happening with very different speeds. Try setting one effect's LFO very slow, and the other noticably faster.

You can also get extremely interesting effects by having the two effects' speeds close, but not identical: then you get an extra modulation or rhythm happening as the two LFOs go in and out of phase, like a Steve Reich piece:

In the Leslie effects, each modulation stage is fairly subtle. If you're a "turn everything up to 10" kind of player, try backing off the depth (or wet/dry knob) on each effect; as they stack the overall effect becomes more pronounced.

There are a lot of modulation effects out there -- phaser, chorus, flanger, tremolo, ring modulation, vibrato and auto-wah for starters, and that's without getting into more exotic things like q-filters and formants. Personally, I get usually tired of hearing a single modulation effect going wa-wa-wa-wa over a whole section of time, but backing off the intensity of each effect and staging them opens up a world of possibilities, and we should then consider that many of these units can take a control voltage to modulate the modulation...

Vintage equipment often gets revived in guitarland. But for me the key is to find inspiration in the old gear and figure out how to do something contemporary with the ideas it provides. Personally I have no interest in faithfully imitating a Leslie speaker, but my ears are still open to the secrets it might contain.