House Music Production : Synthetic percussion

Zaps, clicks and glitches are the bongos of the tech age, and an essential beat element in minimal and electro.

Synthetic percussion has been steadily rising in popularity to the point where it has become a staple ingredient of minimal and electro grooves. Synth-derived hits are used to spice up the rhythm in place of tradicional acoustic and ethnic percussion with zaps, clicks and glitches taking the places of congas, bongos and shakers, introducing detail and rhythm to the groove.

When choosing percussive synth sounds it can be helpful to think in terms of the tonal qualities (in terms of size, shape and frequency) of traditional percussive instruments and use similar sounds for similar purposes. Clicks, high frequency metallic noises, for example, are ideal substitutes for hi-hats; thick, chunky, snappy noises are good snare replacements; and hits with a recognizable pitch can be used instead of toms, bongos and congas.

The most obvious synthetic percussion is that offered on drum machines like the 808 and 909, where the drum sounds are synthesized versions of their real-life cousins, each sound offering a tonal and frequency approximation of the acoustic original. These machines are tweak able, with may of the sounds editable using front panel controls. Toms can be tuned and hat decay times altered, giving producers the tool to fit individual sounds into the mix. This tweak ability accounts for the multiple variations of percussive sounds in vintage beatbox sample collections.

Old-school percussion remains popular today. But house producers have widened their sonic palette to make use of many other sounds  - often used sparsely and picked solely for the way they work in the groove.

Sound Sources

The beauty of synthetic percussion is that the source material can be almost anything, from a vinyl click to a sampled burst of digital feedback.

Sample CDs are a great source of ready-made noises (often in percussive 'hits' folders). Once loaded into a sampler these hits can be sculpted to fit the track's beat using filters envelopes and any number of effects.

Synthetic percussion is also easy to create from scratch. Any analogue synth can be used as a source. For more complex textures such as atonal or metallic sounds, use frequency modulation (FM synthesis), ring modulation, cross modulation or phase distortion techniques. These techniques sound good when used with basic sine waves as the sound source. For subtle sounds spread the tuning between the two oscillators by a few semitones. For more extreme effects detune two by several octaves. Swapping the carrier and modulation modulators around will change the tone dramatically. Digital FM and wavetable synthesis can also create unusual textures.

For more sophisticated sounds try drum synthesizers such as the Waldorf Attack, Elektron Machinedrum or Sonic Charge's micro tonic. These offer a number of drum models specifically designed to create kicks, snares and cymbals. They also have advanced programming functions.

Glitched effects

Some effects are perfect for processing glitch percussion. These include bit-crushers, ring modulators, frequency-shifters, multi-band distortion and FFT-based ('Fast Fourier Transform') filter effects

With bit-crushers, changing the sample-rate value will introduce atonal harmonics to the sound, while lowering the bit-depth will make it more chunky and abrupt.

DestroyFX make an essential series of freeware plugins including Buffer Overide while Audio Damage have the reasonably priced Replicant, Automaton and Big-Seq. These can transform a tiny splinter of sound into something wildly different.

Tip / White noise can be used on it's own or as an extra layer of a percussive sound. Use hi-hats and low-pass filters to shave off unnecessary frequencies around the sound.

Tip / Use reverb to position a sound in the groove. Keep it up-front and snappy with early reflections. Use a long reverb for occasional dramatic hits.

Tip / Distortion transforms thin, weak hits into thick strikes madden with character.

Tip / Any short, simple sine wave blip can be mutated into a lo-fi computerized percussion noise with the help of a bit-crusher. Lower the sampling frequency to introduce tonality.

Reduce the bit length to add noise.

Tip / Up the expression by automating a few parameters in a percussive line over time. Try changing a sound's amp attack / decay, filter cutoff and oscillator pitch.

Tip / Create a hooky, highly personalized beat by introducing a distinctive hit or sound effect into a straight rhythmic pattern. Use the hit sparingly - once in eight bars is often enough.

You can read about the kick drum with more detail in Sample Magic's book "The secrets of house music production".