User manual

Table Of Contents

Prophet-10 User’s Guide

Filter Envelope

The Prophet-10 lter has a dedicated, 4-stage envelope generator

(attack, decay, sustain, release). The Filter Envelope is used to shape the

harmonic characteristics of a synthesized sound by giving you ltering

control with these stages.

This is one of the most important aspects of a synthesized sound. With-

out an envelope, the lter would be static and unchanging. It would stay

open or closed by a xed amount that wouldn’t change over the duration

of a sound. That’s not very expressive or interesting to listen to and it’s

not how most real-world instruments behave.

In general, sounds produced by an acoustic instrument are brighter at

their beginning (the attack stage) and grow mellower as they die out

(the decay and release stages). In other words, their harmonic content

changes over time. This is exactly what the lter envelope is designed to

emulate.

The REV Switch Changes Filter Envelope Shape

The rev switch not only changes lter type, but also the Filter Enve-

lope’s shape/response to match the original Prophet Rev 1/2 or Rev 3

respectively.

The Rev 1/Rev 2 Prophet 5 used SSM envelope generators, and the basic

shape was very at, almost linear. The Rev 3 Prophet-5 used a Curtis

envelope generator, and it had more of a curve than the SSM parts, so it

had a slightly different sound. When you change the lter type with the

rev switch, it also changes the Filter Envelope shape to match the SSM

or Curtis parts, making the Prophet-10 sound authentic in both cases.

Filter Envelope controls