Latin hits, non-stop
Salsa is the most heavily arranged music on this list. A rhythm section, a percussion battery and a horn section all lock to a single two-bar pattern, and once you can hear that pattern the arrangements stop sounding busy and start sounding organised.
The musical grammar of salsa is Cuban: son montuno above all, with mambo, guaracha and cha-cha-cha alongside it. What happened in New York from the 1960s onward was a re-orchestration of that grammar by Cuban, Puerto Rican and other Caribbean musicians working in the same city and the same clubs.
The label itself was a commercial one, applied to a catalogue rather than invented by the players. It stuck because it covered a real thing: a harder, brassier, more urban treatment of Cuban dance forms that spread back across the Caribbean and through Colombia and Venezuela.
Son clave is a two-bar pattern of five strokes, three in one bar and two in the other. It can be played three-two or two-three depending on the arrangement, and the direction is a property of the whole piece, not a choice each player makes.
Every other part is built against it. The piano montuno is a repeating rhythmic figure rather than a chord chart, the bass plays a tumbao that leans away from the downbeat, and the congas, bongo and timbales each carry a different layer of the same cycle.
A typical arrangement opens with sung verses, then moves to the montuno section, where a short repeated chorus alternates with improvised vocal lines. That call and response is the engine of the form.
From there the arrangement usually pushes through a mambo, a written horn passage that raises the intensity, and often a percussion break before the final choruses. Knowing that shape is what lets a programmer place a seven-minute salsa record without losing the hour.