Envelope of sound - in electronic musical instruments, as well as in programs that generate an artificial sound, it's a short record digital audio amplitude, which as far as possible reflect the original wording of "true " musical instruments. Envelopes are usually created by extracting them from the digital records sound best instruments. Program or an electronic instrument "playing " in the appropriate moments earlier saved by giving outlines broad impression "playing " in a standard instrument. Envelopes are usually the form known acronym "ADSR ": Attack - growing, Dec