Yoshimi User Manual ~ Oscillator Waveform

## Add/Pad Waveforms

This waveform editor is used for both AddSynth and PadSynth. There are quite a lot of controls that are highly specialised. Unfortunately, it is difficult to describe their operation without deep understanding of the mathematics involved.

At the top there are a pair of graphic views. On the left is the complete oscillator with all filters and harmonic effects applied, and on the right the basic wave it is derived from.
The narrow imags at the top are the harmonic distribution. Each vertical bar represents one actual harmonic. This is most obvious with a sinewave base.
The larger image below is a more familiar waveform as would be displayed on an oscilloscope.
Note: PadSynth doesn't have the Phase or Harmonic Randomness controls. Instead it has an Apply button, as the wavetable has to be rebuilt.

### Controls

The bank of sliders control 128 individual harmonics. The top row being amplitude, and the bottom row, relative phase.
Mag. Type (magnification type) This controls the amount of effect the harmonic sliders have on the waveform. Higher negative values giving less range but finer control.
Phase Randomness Provides a small random variation to the overall phase. Only really noticable with multiple voices.
Harmonic Randomness Provides a small amplitude randomness to each harmonic.
Base Function Decides the basic waveshape. This is applied per harmonic so, for example, a square wave can become a complex stepped wave.
Par. (for base function). This modifies the actual mathematical formula. For example, with the control anti-clockwise the 'power' wave is logarithmic and in the other direction, is exponential.
B.F.Mod (base function modulator) This sets the type and enables the three modulation controls for the base function. These change the modulation formula in ways we don't currently understand.
Use as base Turns the entire oscillator into a user base function.
Wsh (waveshape) Modifies the overall waveshape dependent on its parameter setting.
Filter (harmonics filter) Various filter types applied to the waveshape. The first parameter is the filter degree and the second one seems to be the Q factor.
F (first) If checked, this moves the filter ahead of the waveshaping (if it's used).
Mod. (harmonics modulator) This sets the type and enables the three modulation controls for the overall waveform. These change the modulation formula in ways we don't currently understand.
Sp. adj. (spectrum adjustment) This provides three different types of adjustment of the frequency spectrum of the overall waveform. The control varies the degree of change.
Harmonic Shift Changes the harmonic position in ways we don't currently understand.
Shift 1st Moves this function ahead of both Waveshaping and Filtering.
Adpt. Harm (adaptive harmonics) Changes the positions and amplitudes of the harmonics. The best way to understand the relationship between the slider and two parameter knobs is to watch the oscillator spectrum display (top left) while adjusting them.
Clear Returns the main harmonics sliders to their default positions.
Sine Coverts the the base function to a sine wave, producing the same final result by setting all the harmonics to the equivalent amplitudes and phases.

Next (Resonance) To AddSynth
To PadSynth