The PolySynth is a flexible and powerful synth engine featuring 48 note polyphony and capable of producing almost any sound you want.
It is very similar to the MUX except that it can only use a selection of modules, the ones that are capable of doing polyphonic processing.
Although very similar as the MUX, within a PolySynth not all types of modules can be used, only modules that are capable of doing polyphonic processing.
For example, you can use an oscillator inside PolySynth but you cannot use a MuVerb.
To know which modules can be used inside PolySynth, simply open the PolySynth editor and add a new module, the popup list will tell you which modules are available.
Note that e.g. an oscillator can also be used outside PolySynth, e.g. in a MUX patch, but then the oscillator is monophonic!
The PolySynth is typically used within a MUX. Then the MUX can include effects like reverb and echo that will be applied to all of the PolySynth voices.
If you do want to build your own synth architectures, but you don't yet have the necessarry background info, visit this interesting page on Wikipedia.org: Intro To Sound Synthesis
Every PolySynth patch should have a "Main Envelope". This envelope defines when a PolySynth voice is finished.
For example, a patch with a short amplifier envelope and with a long filter envelope.
By default, the PolySynth will only finish the voice when all envelopes are finished.
But in this case this would create voices which will play (and consume CPU power!) for a long time, while you only hear them for a short time.
So indicating a proper Main Envelope is important in optimizing the voice allocation algorithm, and regarding CPU consumption.
Indicating a proper Main Envelope is the responsibility of the patch designer! A good patch has set a proper Main Envelope.
Most of the time the main envelope is the ADSR (or Multi-Point Envelope) that controls the final amplifier.
The Main Envelope can be set by right-clicking an envelope and choosing "Set As Main Envelope".