Pushing the Envelope (of sound)

Attack, decay, sustain, release — those four control parameters have helped literally create the shape of modern electronic music through what’s called envelope generators. Bob Moog didn’t invent them, but their inclusion on early Moog synthesizers was a fundamental piece in constructing their iconic sound.

Fundamental enough that The Bob Moog Foundation and Asheville Area Arts Council have announced “Pushing the Envelope: Attack, Decay, Sustain, Release,” a three-week exhibit in the River Arts District showcasing Asheville artists’ interpretations of what it means to shape sound through envelopes, as well as workshops on electronic synthesis and sound visualization.

The show opens Saturday, July 9 at The Artery, where 12 local artists will have their work displayed around a collection of analog electronic instruments, schematics and notes from Moog’s archive, with a focal point on the history of the company’s sound and how the envelope generator came into it.

Artist contributions, like Gabriel Shaffer’s painting and sculptural theremin installation, focus on interactivity and imagining just exactly how sound is shaped through envelopes. Another artist, photographer Shaun Hollingsworth, will have his series on the inner workings of Moog electronics on display. Hollingsworth’s work finds the beauty in the often hand-assembled circuit boards inside Moog effects and filters. Other local artists featured include letterpress artist Bridget Elmer, percussionist River Guerguerian, and experimental musician Elisa Faires.

A suggested $5 donation for workshops includes discussions on topics like the ubiquity of music and cymatics, the study of visible sound and vibration. For a complete schedule and more information, check out moogfoundation.org.

So what is exactly is an envelope?

Think about tapping a key on a synthesizer — besides the electronics required to emulate a specific voice or keyboard sound, there are certain factors that change how long it takes the note to rise, how long the note rings-out, etc. Most commonly, these are controlled through attack, sustain, decay and release (ADSR). It’s not as complicated as it sounds – if an envelope filter were set to modulate simply the amplitude of a synthesizer voice, for instance, attack would control the time it took for the sound to reach its maximum volume, decay would control the time it took the volume to descend to the level specified by sustain, sustain represents the level which the note is held at until the key is released and release is the time the note continues after you let up on the key.

ADSR is simply part of constructing the sound a synthesizer makes. You’ll find similar controls on Virtual Studio Technology (VST), the set of tools at the forefront of computer-generated music. Want to find out even more? Wikipedia is your friend.