"Easy Snappin'," recorded by Theophilus Beckford around 1959, is frequently cited by historians as a transitional record between Jamaican R&B/shuffle and the ska sound that would emerge within a year or two - one of the clearest audible steps in ska's formation.

The lacquer-coated disc a studio cuts one at a time, called soft wax because it wears out after a few dozen plays. It was meant as a test pressing on the way to a stamper; Jamaica made it a finished product instead. A dubplate is an acetate, and the whole economy of exclusive versions, specials and clash tunes rests on a format that was never supposed to leave the cutting room.

Late-1950s Kingston sound system remembered as the set where Percival "Sir Lord Comic" Wauchope worked first as a star dancer and then, from about 1959, as a toaster in the style pioneered by Count Machuki.

Adolphus "Addie" Shawn, from eastern Kingston, founded Addies Hi-Fi in Crown Heights, Brooklyn in 1983. It began as small as a sound can begin, one turntable and one speaker, with Shawn selecting alongside his friend Lenky. He then handed the set to his cousin Father Ethen, who built it out; with the veteran selector Danny Dread recruited it became Addies International, and the run of wins over New York and Jamaican sounds earned it the name King Addies. Through the 1980s and 1990s the sound gave early platforms to Super Cat, Shabba Ranks, Buju Banton, Beenie Man, Bounty Killer, Maxi Priest and Sean Paul.

Albert Malawi was a selector and vocalist for the Twelve Tribes sound Jah Love Muzik and a drummer in Augustus Pablo's circle, one of the figures linking sound-system practice to Rastafari organisation.

The iron-cored transformer that couples a valve amplifier to its speakers; in Jamaica the winding of these coils by hand, as King Tubby did to expand bass depth, became a signature electronics skill of the sound-system craft.

The heavy low-frequency loudspeaker at the heart of a bass bin, typically a fifteen-, eighteen- or twenty-one-inch cone, whose size and excursion the box is built around. Sound systems prize robust, high-excursion drivers.

A ported box loading that tunes a port to extend low frequencies, contrasted in sound-system practice with the horn-loaded scoop favoured for reggae weight. Used where a shallower, less horn-coloured bass was wanted.

A Greenwich Farm street cited in sound-system history as the location associated with Coxsone Dodd's early operations and West Kingston dance culture.

Hedley Jones's radio, electronics and record shop on King Street, Kingston; the amplifier Jones built in 1947 to play records outside the shop is credited as the first purpose-built sound-system amplifier in Jamaica.