Modulator Class

Modulator Class

Represents a single Modulator.

Properties

All numbers

sourcePolarity

The primary source's polarity.

sourceDirection

The primary source's direction.

sourceUsesCC

If the primary source uses a MIDI controller.

sourceIndex

The index of the primary source.

sourceCurveType

The primary source's curve types.

secSrcPolarity

The secondary source's polarity.

secSrcDirection

The secondary source's direction.

secSrcUsesCC

If the secondary source uses a MIDI controller.

secSrcIndex

The index of the secondary source.

secSrcCurveType

The secondary source's curve types.

modulatorDestination

The destination of the modulator. -1 if linked as it's not supported.

transformType

The transform type to apply.

transformAmount

The amount of transform to apply.

Modulator sources

Below is the table of modulator sources if the usesCC flag is set to 0.

Index	Name
0	No controller = 1
2	Note on velocity
3	Note on key number
10	Poly pressure
13	Channel pressure
14	Pitch Wheel
16	Pitch Wheel range
127	Link (UNSUPPORTED)

Modulator curve types

Below are the defined curve types of modulators:

• 0 Linear - normal linear scale
• 1 Concave - exponential ramp
• 2 Convex - logarhitmic ramp
• 3 Switch - 0.5 and below is 0 (or -1 for bipolar), above is 1

Default Modulators

Below is the default modulator list for SpessaSynth.

Note: cB - centibels, 1/10 of a decibel

Source	Secondary source	Destination	Transform amount	Notes
Note On velocity Negative Unipolar Concave	No controller	Initial attenuation	960 cB	SF2 Default
Modulation Wheel Positive Unipolar Linear	No controller	Vibrato LFO to pitch	50 cents	SF2 Default
Volume Negative Unipolar Concave	No controller	Initial attenuation	960 cB	SF2 Default
Channel Pressure Positive Unipolar Linear	No controller	Vibrato LFO to pitch	50 cents	SF2 Default
Pitch Wheel Positive Bipolar Linear	Pitch wheel range Positive Unipolar Linear	Fine tune	12700 cents	SF2 Default
Pan Positive Bipolar Linear	No controller	Pan	500 percent	SF2 Default
Expression Negative Unipolar Concave	No controller	Initial attenuation	960 cB	SF2 Default
Reverb depth Negative Unipolar Linear	No controller	Reverb effects send	1000 percent	SF2 Default, amount increased
Chorus depth Negative Unipolar Linear	No controller	Chorus effects send	1000 percent	SF2 Default, amount increased
Poly Pressure Positive Unipolar Linear	No controller	Vibrato LFO to pitch	50 cents	⚠️ NOT STANDARD ⚠️
CC 92 depth Positive Unipolar Linear	No controller	Mod LFO to volume	24 cB	⚠️ NOT STANDARD ⚠️
CC 72 Positive Bipolar Linear	No controller	Volume envelope release	1200 timecents	⚠️ NOT STANDARD ⚠️
CC 74 Positive Bipolar Linear	No controller	Initial filter Cutoff	6000 abs cents	⚠️ NOT STANDARD ⚠️
CC 71 Positive Bipolar Linear	No controller	Initial filter Reasonance	250 cB	⚠️ NOT STANDARD ⚠️

Reverb and Chorus modulators

SpessaSynth has custom behavior for these modulators, emulating BASSMIDI:

• The modulators affected are all modulators that use Reverb depth Negative Unipolar Linear or Chorus depth Negative Unipolar Linear as a primary source and *No Controller as the secondary source and either reverbEffectsSend or chorusEffectsSend as the destination
• The transform amount is multiplied by 5 if initial transform amount is below 1000
• If the transform is multiplied, it is capped at 1000

Reasoning

Amount of 200 (SF2 default) is too low for these modulators, according to Ian from Un4seen. I agree with him, and also set the default to 1000 (actually it's 200 multiplied by 5 which is 1000). But this poses a few problems without using the solution above:

• soundfonts that assume default reverb of 200 will have almost inaudible effects. For example, a soundfont might want to slightly decrease the reverb, by setting it to 150 for example. It is way less than the default 1000 and the approach above will make it 150 * 5 = 750 which is still less than default, but more audible.
• This approach still allows to disable these modulators.
• Some soundfonts assume a default reverb of 1000 and set some to 800 or similar. Using the default 200 will cause big imbalance between the custom and default modulators.