Visconti recorded Bowie's vocals in a large space using three microphones placed 9 inches (23 cm), 20 feet (6.1 m), and 50 feet (15.2 m) away, respectively. A different gate was applied to each microphone so that the farther microphone was triggered only when Bowie reached the appropriate volume, and each microphone was muted as the next one was triggered. "Bowie's performance thus grows in intensity precisely as ever more ambience infuses his delivery until, by the final verse, he has to shout just to be heard....The more Bowie shouts to be heard, in fact, the further back in the mix Visconti's multi-latch system pushes his vocal tracks [dry audio being perceived as front and ambience pushing audio back in the mix], creating a stark metaphor for the situation of Bowie's doomed lovers shouting their love for one another over the Berlin wall". Trance gating Envelope following (also called trance gating because of its prevalence in trance) is the use of a gate on a track additional to the one it attenuates, so called because the latter's amplitude profile will then match or closely follow that of the first. Envelope following may be used to create syncopated rhythms or to tighten sloppy performances. For example, a synth pad may play whole notes while keyed to a guitar or percussion part. Examples include DJ Nexus's "Journey into Trance" (1:11), Chic's "Everybody Dance", and Diana Ross's "Upside Down". Sound reinforcement Noise gates play an important role in drum mic'ing in heavy metal shows. The drum and cymbal mic channels will typically have noise gates so that the mics will only be turned on when the specific drum or cymbal is being played. This dramatically reduces "bleeding" between the drum mics. This is used to reduce audio feedback triggered by other highly amplified sounds onstage. See also Dynamic noise limiter Audio spill References External links SOS's Advanced Gating Techniques Part 1/2 SOS's Advanced Gating Techniques Part 2/2 Audio effects Noise reduction Dynamics processing