Bucket-brigade chorus

ATMOSYNTH built-in module

The Roland Juno-6's chorus as a module, as one was heard to play: one triangle wave moving two bucket-brigade delay lines in opposite directions, one heard on each side beside the sound that came in, so while the left copy falls behind the right one catches up and the sound spreads out between the speakers. Mode is the Juno's three buttons. II sweeps each line between 1.14 and 5.60 milliseconds about two thirds of a time a second (0.68 Hz), and I is the same sweep slower (0.405 Hz), the gentle one. The copies' pitch moves about a ninth of a semitone either way in II and about half that in I, and what the wide sweep adds is the slow swirl of their peaks and notches across the sound. I+II is a quick shallow shimmer, 9.75 times a second between 3.3 and 3.7 milliseconds, its wave rounded nearly to a sine, which is closer to a rotary speaker than a chorus. Changing Mode while a note sounds glides from one to the next rather than clicking. Mix goes from the sound alone to the two lines alone, keeping the sound about as loud as it went in; it starts at 0.6, the Juno's own balance, where each line is a little under three decibels louder than the sound beside it, which is most of how wide the Juno is. Half way the two are at one level. What makes it a bucket-brigade chorus rather than the plain one: the lines are dark, filtered either side as a bucket-brigade line has to be, so the copies are softer than the sound beside them; a line is a row of buckets handed along at a clock, so as it lengthens its clock slows and it darkens a little further, and brightens again as it shortens, with every sweep; loud chords come out of the line rounded off, where quiet ones pass untouched; and the line hisses. Hiss is how much: where it starts, as quietly as the Juno, some seventy decibels under what is played, and at the top ten times that, a faint wash that is plainly there. It hisses under whatever is played and for a second after the last of it, then lets the hiss go over a second more, so a patch that has stopped playing falls silent and an export of it ends; the next sound brings the hiss straight back. A mono sound in comes out in stereo; a stereo one keeps its two sides in the dry path, and the lines are handed the two together. It holds a few milliseconds of sound past the note that made it, so it is added shared, as an effect at the end of the chain is. Version 1 is the same chorus at the figures published for the Juno-60, its sweep narrower and quicker, its lines at the sound's own level and its hiss twenty-two decibels louder. For a chorus with every setting free — its rate, its delay, its depth, the shape of its wave — the plain chorus is beside it. This module carries code, because a bucket-brigade line's darkening follows its clock, and its clock is the number of buckets divided by the delay, which nothing else here can divide by; and because nothing else here makes the random signal its hiss is.