Sound · aka Noise gate, Sidechain gate, Trance gate
Gated vocal / gated pad
A gate is an audio effect that chops a sustained sound — a vocal, a pad or a synth chord — into rhythmic on/off segments in time with the track. In classic trance the 'trance gate' rhythmically stutters a chord pad in eighth or sixteenth notes across a breakdown, producing the characteristic pulsing pad texture heard on records like Alice DeeJay's 'Better Off Alone' and Cygnus X's 'Superstring'.
Producers built classic-trance gates two ways. The traditional method used a noise gate keyed by a rhythmic sidechain — usually a hi-hat or ghost kick — so the pad only passed through when the trigger sound was above threshold. The later shortcut route used an LFO on the pad's amplitude, which achieved the same on/off pattern without the sidechain routing. Either way, the result is a wall of chord sound that pulses in time with the kick, and it is one of the two or three most identifiable sound-design tricks of the late-1990s / early-2000s peak era.
Gates are almost always paired with a filter sweep or reverb tail, so the gated pad rides underneath the lead melody and rises during the breakdown to signal an incoming drop.