Disco

Disco runs roughly 110-130 BPM with a kick drum on every beat, hi-hats opening on the off-beats, and a bass line that walks in octaves on every quarter note. On top of that rhythm engine sit lush string sections, punchy horn arrangements, choppy rhythm-guitar chords, and gospel-trained lead vocals that often resolve into full choral hooks. Tracks were mastered for the dancefloor at extended five-to-ten-minute lengths so DJs could blend them seamlessly. The arrangements are essentially orchestral pop scaled for a club sound system, which is why disco productions feel both bigger and tighter than most chart pop of the same period.

Disco grew out of early-1970s New York gay, Black, and Latino club culture — venues like the Loft and the Paradise Garage, and DJs such as David Mancuso, Larry Levan, and Nicky Siano. Producers Giorgio Moroder, Nile Rodgers and Bernard Edwards of Chic, and the writer-producer team of Kenny Gamble and Leon Huff in Philadelphia gave it a recognisable studio sound by the mid-1970s. The 1977 film 'Saturday Night Fever' and the Bee Gees soundtrack pushed it into the global mainstream, and Moroder's work with Donna Summer — particularly 'I Feel Love' the same year — replaced the live rhythm section with a sequenced synth bass, prefiguring almost every dance genre that followed. A racist and homophobic backlash culminating in 1979's 'Disco Demolition Night' at a Chicago baseball stadium pushed disco off pop radio almost overnight, but the music kept going underground and mutated into house and garage.

Tune in to the octave bass first — it is the single most identifiable disco signature. Then notice how the rhythm guitar plays very short, percussive 16th-note chords rather than strumming, and how the string section is used almost like a horn riff, stabbing on the off-beats rather than sustaining. On the longer 12-inch mixes, listen for the 'break' — an extended section where most of the band drops out and just drums, bass, and percussion play, designed to give DJs a clean stretch to mix into the next record.

If you only hear one song, make it Donna Summer, 'I Feel Love' (1977) — Moroder's sequenced synth bass is essentially the blueprint for the next forty years of electronic dance music. For an album, Chic's 'C'est Chic' (1978) shows the Rodgers-Edwards rhythm section at its peak.

The word disco is a clipping of the French 'discotheque', a venue where recorded music replaced a live band — a then-radical idea that French wartime jazz clubs adopted because Nazi censors had banned American records from public broadcast.