The Beat

An identifying characteristic of both rap and hip-hop is the heavy use of drum loops. Rather than trying to imitate the performance of acoustic drums played by a human -- groove, interpretation, variation, artistic looseness, sloppiness, mistakes and all -- drum loops offer rhythms with the mechanical steadiness only a machine can produce. Drum loops emphasize the machine in the words ‘drum machine’. Beyond feel, drum loops have a sonic signature as well: the sounds are ‘low fidelity’ almost by design. The audio goal is not the sound of an acoustic drum kit in a room, but the sound of ‘the street’ – unique, distorted, phased, flanged, anything-goes sounds that whet your listeners’ interest. Grooves that can only be created through the sampled and synthesized world of the drum machine are a centerpiece of hip-hop and rap tunes. The artistic appeal is increasingly universal as drum loops have crossed over into more mainstream music, with success. One pop music imitation comes in the form of a drum loop break. Peter Gabriel’s “Steam” on his most recent release US provides a good example. The great drummer Manu Katche plays electronic drums for that drum loop ‘sound’ throughout the tune. And it is showcased in the bridge, a drum and bass breakdown. It is also worth checking some mega-selling albums offering a human drum loop. U2’s Achtung Baby and Depeche Mode’s Songs of Faith and Devotion contain many songs in which a human drummer in some cases does a damn good job of sounding quantized – human imitating machine – and in other cases actually plays along with a sequenced drum loop, a human doubling the sounds of the drum machine.

Rap and hip-hop musicians have led the creative expedition into uses of drum machines. One proven strategy is to use a drum loop as the rhythmic foundation of a song. It is often a very steady pattern full of notes (hi-hat: steady eighth and/or sixteenth notes; snare: beats two and four plus accents and grace notes; kick: simple one bar pattern, constant quarter notes is not unusual). The time of the song is unmistakable. The tempo is established through the entire drum loop pattern, based not solely on the kick, but on the whole ‘drum kit.’ This provides a strong, paced groove over which syncopation is usually added through rapping, scratching, additional percussion, etc. with tremendous results. The loop effectively becomes a drone which, in spite of any complexity it may contain, conveys a beat impossible to ignore. Any change-up of the pattern is immediately noticed: dropped notes, breakdowns and complete stops are used for powerful rhythmic and musical effects.

With the beat well established through the entire drum loop arrangement, the kick may no longer be the primary communicator of meter. As a result, it is freed from the spectral constraints discussed in our earlier look at the kick and bass in rock and pop music. Recall that the ‘rock and roll kick’ can be thought of as having two distinct parts: an initial attack which covers a broad band of frequencies from 100 Hz. to 15 KHz. followed by a (pitchless) decay in the 40 Hz to 100 Hz range. The initial broad-band hit, the ‘click,’ cuts through the mix and conveys the ‘rock and roll meter’ of the tune. Hip-hop and rap, with drum loops keeping time, don’t need a kick with click. The kick is part of an entire drum loop arrangement and can have a more interesting timbre and envelope. And one listen will confirm it: rap and hip-hop kicks definitely have interesting timbre and envelope! Very common is the nearly attackless drum machine thump. It can have a variety of sounds which might, for example, be described as sounding like a wet cardboard box or a heartbeat. Look into Digable Planets’ “Last of the Spiddyocks” on the Grammy-winning Reachin’ for a kick that simply doesn’t ever happen with an acoustic drum. It has an enormous, deep tone and positively no attack – so big, and yet so gentle. A particularly interesting kick can be found in The Beastie Boys “Paul Revere” on the multi-platinum record, Licensed to Ill, which uses a kick/gated oscillator combination (described below), but played backwards. Don Henley and Sting haven’t gotten around to this one yet.