## AddSynth

AddSynth is the most complex and feature filled engine, so is split up into various context levels. Although based on well-known additive synthesis, Yoshimi extends that considerably.
There are 8 voices that can all interact with each other to some degree. Each of those voices has a waveform oscillator and optionally a modulation one with five different modulation types. It also has Unison capability - effectively sub-voices.
The oscillators themselves have a wide range of waveform shaping controls, almost all of which can be changed in real time.
The image shows your entry point with all the global controls. Much of this actually consists of standardised inserts that are used across all engines. Detailed descriptions of these are provided in the following sections.

Volume and Panning
Filter Type and Style
Envelope
LFO

There are also subsections of this specific engine.
For a start, you can have up to eight quite different Voices and the leftmost button at the bottom of the window is the entry point for these.

Next in line is a button for the Voice List, which as its name suggests is a list of all the voices, whether active or not.

The last of these buttons gives access to an overall Resonance that can be applied to the engine.

### Local Controls

Stereo Determines whether the whole of this engine is to be Stereo or Mono. If the box is not checked (i.e. Mono), there will be no spread to the sound, but the Panning controls will not be affected, and neither will the stereo spread of any part effects.
Rnd Grp (random group) Normally each Voice has it's own harmonic amplitude random element. If this is checked, then all voices that use the same waveform oscillator will be grouped so they have the same harmonic randomness, assuming this has been set in the Waveform window.
D.Pop (de-pop) Sets the time of a very short attack ramp up, to suppress the click some sounds might produce.
P.Str. (punch strength) Sets the amount of amplitude boost at the start of a note.
P.t. (punch time) Determines how long the punch should last.
P.Stc. (punch stretch) Increasing this will give a longer punch time at low pitch notes relative to high ones.
P.Vel. (punch velocity) determines how much the punch amplitude depends on keying speed.
Detune Detunes the engine by a small amount.
Octave Allows you to change the overall pitch up or down by up to eight octaves.
relBW (relative bandwidth) Modifies the amount individual voice and unison detunes can deviate from the overall value.
Detune Type The menu options control the amount of detune of the slider and whether it is a linear change or exponential (i.e. has more effect the further away it is from the centre position).
Coarse Detune The inner single arrows make a coarse step change to the detune, and the outer double ones change by ten times as much.

Next (SubSynth Engine)
PadSynth Engine