Guitars are naturally percussive—pluck a string, and a quick transient decays rapidly. Although we often try to violate the laws of physics with compression, feedback, limiting, distortion, E-Bows, and other techniques that increase sustain, there’s a parallel universe where the goal is making the guitar more percussive. Of course, muting strings is very percussive, but we can take this concept much further with signal processors.
Expanders. These are the opposite of compressors (which above a certain threshold, produce less output for an equivalent input increase). With expanders, signals below a threshold produce less output for a given input decrease. For example, if the input is below the threshold, and it drops 10dB, with 1:2 expansion, the output will drop 20dB. With 1:4 expansion, it will drop 40dB. This can make pick and note attacks super-prominent, while hastening decays. Expansion can help guitars avoid conflicts with drums that have a long ring, but with a fairly high threshold, they can provide a super-percussive effect. This also affects downstream processors, such as distortion (where the peaks distort much more than the rest of the signal) and delay, where you’ll get a quick “hit,” but not much else. A corollary technique is using expansion not on your main-guitar signal, but on a bus that your guitar feeds. With a reverb bus, for example, you’ll hear a quick ambient spike, which then gets out of the way so that the reverb doesn’t step on other instruments.
Noise Gates. These are like extreme expanders. Below a threshold, the guitar sound mutes completely (although noise gates usually allow for less drastic options). This can produce an extremely percussive sound, but you’ll need to pick with predictable force, so that the signals you want to hear are above the threshold, and the signals you want to mute are below it. You can also sidechain a noise gate to the guitar’s audio on and off using another instrument as a trigger. (I covered this option in a column a few years ago—search for “Hyper-Rhythm Guitar” at guitarplayer.com.)
Cutting. This involves cutting guitar parts recorded on hard disk, so it’s not suitable for live performance. For example, suppose you want the guitar to lock perfectly to a synthbass part (something I often need for EDM). MIDI notes trigger the bass part, so you can line up the MIDI track with the guitar’s audio track, and then chop the guitar part into slices that last exactly as long as the MIDI notes (see the example). You’ll probably need short fades (around 3 to 7 milliseconds) on the chopped guitar clips to avoid clicks at the beginning and end, but most DAWs let you apply mass fades to groups of selected clips.
DAW Tremolo. Some of the tremolo effects in DAWs provide pulse and sawtooth waveforms, in addition to the traditional sine or triangle waves. These not only impart a percussive quality, but often can sync to the host program tempo for rhythmic effects. Chopping up a power chord with percussive tremolo can be very cool.