What are the values ​​that can be applied to the inputs of the synth preset, gain, LFo frequency ...

You can also look in the code which defines the UPROPERTIES. I actually specified in many cases a UIMin/UIMax and ClampMin/ClampMax for most params. The UIMin specifies the range for the UI, but the Clamp specifies the true min/max. You have different ranges because of the 2 different input methods – one is a UI slider, but you can also enter values in by hand/typing. The UIMin/Max values are chosen for reasonable slider-style input but the clamps are the full range.


USTRUCT(BlueprintType)
struct SYNTHESIS_API FModularSynthPreset : public FTableRowBase
{
	GENERATED_USTRUCT_BODY()

	// Whether or not to allow multiple synth voices.
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	uint32 bEnablePolyphony : 1;

	// What type of oscillator to use for oscillator 1
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	ESynth1OscType Osc1Type;

	// The linear gain of oscillator 1 [0.0, 1.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "1.0", UIMin = "0.0", UIMax = "1.0"))
	float Osc1Gain;

	// The octave of oscillator 1. -8.0, 8.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "-8.0", ClampMax = "8.0", UIMin = "-8.0", UIMax = "8.0"))
	float Osc1Octave;

	// The semi-tones of oscillator 1. -12.0, 12.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "-12.0", ClampMax = "12.0", UIMin = "-12.0", UIMax = "12.0"))
	float Osc1Semitones;

	// The cents (hundreds of a semitone) of oscillator 1. -100.0, 100.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "-100.0", ClampMax = "100.0", UIMin = "-100.0", UIMax = "100.0"))
	float Osc1Cents;

	// The pulsewidth of oscillator 1 (when using a square wave type oscillator). [0.0, 1.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "1.0", UIMin = "0.0", UIMax = "1.0"))
	float Osc1PulseWidth;

	// What type of oscillator to use for oscillator 2
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
		ESynth1OscType Osc2Type;

	// The linear gain of oscillator 2 [0.0, 1.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "1.0", UIMin = "0.0", UIMax = "1.0"))
	float Osc2Gain;

	// The octave of oscillator 2. -8.0, 8.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "-8.0", ClampMax = "8.0", UIMin = "-8.0", UIMax = "8.0"))
	float Osc2Octave;

	// The semi-tones of oscillator 2. -12.0, 12.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "-12.0", ClampMax = "12.0", UIMin = "-12.0", UIMax = "12.0"))
	float Osc2Semitones;

	// The cents (hundreds of a semitone) of oscillator 2. -100.0, 100.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "-100.0", ClampMax = "100.0", UIMin = "-100.0", UIMax = "100.0"))
	float Osc2Cents;

	// The pulsewidth of oscillator 2 (when using a square wave type oscillator). [0.0, 1.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "1.0", UIMin = "0.0", UIMax = "1.0"))
	float Osc2PulseWidth;

	// The amount of portamento to use, which is the amount of pitch sliding from current note to next [0.0, 1.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "1.0", UIMin = "0.0", UIMax = "1.0"))
	float Portamento;

	// Enables forcing the oscillators to have no stereo spread.
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	uint32 bEnableUnison : 1;

	// Whether or not oscillator sync is enabled. Oscillator sync forces oscillator 2's phase to align with oscillator 1's phase.
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	uint32 bEnableOscillatorSync : 1;

	// The amount of stereo spread to use between oscillator 1 and oscillator 2 [0.0, 1.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "1.0", UIMin = "0.0", UIMax = "1.0"))
	float Spread;

	// The stereo pan to use. 0.0 is center. -1.0 is left, 1.0 is right.
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "-1.0", ClampMax = "1.0", UIMin = "-1.0", UIMax = "1.0"))
	float Pan;

	// The frequency to use for LFO 1 (in hz) [0.0, 50.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "50.0", UIMin = "0.0", UIMax = "50.0"))
	float LFO1Frequency;

	// The linear gain to use for LFO 1 [0.0, 1.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "1.0", UIMin = "0.0", UIMax = "1.0"))
	float LFO1Gain;

	// The type of LFO to use for LFO 1
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	ESynthLFOType LFO1Type;

	// The mode to use for LFO 1
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	ESynthLFOMode LFO1Mode;

	// The built-in patch type to use for LFO 1 (you can route this to any patchable parameter using the Patches parameter)
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	ESynthLFOPatchType LFO1PatchType;

	// The frequency to use for LFO 2 (in hz) [0.0, 50.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "50.0", UIMin = "0.0", UIMax = "50.0"))
	float LFO2Frequency;

	// The linear gain to use for LFO 2 [0.0, 1.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "1.0", UIMin = "0.0", UIMax = "1.0"))
	float LFO2Gain;

	// The type of LFO to use for LFO 2
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	ESynthLFOType LFO2Type;

	// The mode to use for LFO 2
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	ESynthLFOMode LFO2Mode;

	// The built-in patch type to use for LFO 2 (you can route this to any patchable parameter using the Patches parameter)
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	ESynthLFOPatchType LFO2PatchType;

	// The overall gain to use for the synthesizer in dB -90.0, 20.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "-90.0", ClampMax = "20.0", UIMin = "-90.0", UIMax = "20.0"))
	float GainDb;

	// The amplitude envelope attack time (in ms) [0.0, 10000]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", UIMin = "0.0", UIMax = "10000.0"))
	float AttackTime;

	// The amplitude envelope decay time (in ms)[0.0, 10000]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", UIMin = "0.0", UIMax = "10000.0"))
	float DecayTime;

	// The amplitude envelope sustain amount (linear gain) [0.0, 1.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "1.0", UIMin = "0.0", UIMax = "1.0"))
	float SustainGain;

	// The amplitude envelope release time (in ms) [0.0, 10000]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", UIMin = "0.0", UIMax = "10000.0"))
	float ReleaseTime;

	// The built-in patch type for the envelope modulator
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	ESynthModEnvPatch ModEnvPatchType;

	// The built-in patch type for the envelope modulator bias output. Bias is when the envelope output is offset by the sustain gain.
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	ESynthModEnvBiasPatch ModEnvBiasPatchType;

	// Whether or not to invert the modulation envelope
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	uint32 bInvertModulationEnvelope : 1;

	// Whether or not to invert the modulation envelope bias output
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	uint32 bInvertModulationEnvelopeBias : 1;

	// The "depth" (i.e. how much) modulation envelope to use. This scales the modulation envelope output. [0.0, 1.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "1.0", UIMin = "0.0", UIMax = "1.0"))
	float ModulationEnvelopeDepth;

	// The modulation envelope attack time (in ms) [0.0, 10000]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "10000.0", UIMin = "0.0", UIMax = "10000.0"))
	float ModulationEnvelopeAttackTime;

	// The modulation envelope decay time (in ms) [0.0, 10000]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "10000.0", UIMin = "0.0", UIMax = "10000.0"))
	float ModulationEnvelopeDecayTime;

	// The modulation envelope sustain gain (linear gain) [0.0, 1.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "1.0", UIMin = "0.0", UIMax = "1.0"))
	float ModulationEnvelopeSustainGain;

	// The modulation envelope release time (in ms) [0.0, 10000]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "10000.0", UIMin = "0.0", UIMax = "10000.0"))
	float ModulationEnvelopeReleaseTime;

	// Whether or not to use legato mode.
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	uint32 bLegato : 1;

	// Whether or not to use retrigger mode.
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	uint32 bRetrigger : 1;

	// The output filter cutoff frequency (hz) [0.0, 20000.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "20000.0", UIMin = "0.0", UIMax = "20000.0"))
	float FilterFrequency;

	// The output filter resonance (Q) [0.5, 10]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.5", ClampMax = "10.0", UIMin = "0.5", UIMax = "10.0"))
	float FilterQ;

	// The output filter type (lowpass, highpass, bandpass, bandstop)
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	ESynthFilterType FilterType;

	// The output filter circuit/algorithm type (one-pole ladder, ladder, state-variable)
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	ESynthFilterAlgorithm FilterAlgorithm;

	// Whether or not stereo delay is enabled on the synth
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	uint32 bStereoDelayEnabled : 1;

	// The stereo delay mode of the synth
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	ESynthStereoDelayMode StereoDelayMode;

	// The stereo delay time (in ms) [0.0, 2000.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "2000.0", UIMin = "0.0", UIMax = "2000.0"))
	float StereoDelayTime;

	// The amount of feedback in the stereo delay line [0.0, 1.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "1.0", UIMin = "0.0", UIMax = "1.0"))
	float StereoDelayFeedback;

	// The output wet level to use for the stereo delay time [0.0, 1.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "1.0", UIMin = "0.0", UIMax = "1.0"))
	float StereoDelayWetlevel;

	// The ratio between left and right stereo delay lines (wider value is more separation) [0.0, 1.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "1.0", UIMin = "0.0", UIMax = "1.0"))
	float StereoDelayRatio;

	// Whether or not the chorus effect is enabled
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	uint32 bChorusEnabled : 1;

	// The depth of the chorus effect [0.0, 1.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "1.0", UIMin = "0.0", UIMax = "1.0"))
	float ChorusDepth;

	// The amount of feedback in the chorus effect [0.0, 1.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "1.0", UIMin = "0.0", UIMax = "1.0"))
	float ChorusFeedback;

	// The chorus LFO frequency [0.0, 20.0]
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset", meta = (ClampMin = "0.0", ClampMax = "20.0", UIMin = "0.0", UIMax = "20.0"))
	float ChorusFrequency;

	// The modular synth patch chords to use for the synth. Allows routing the LFO1/LFO2 and Modulation Envelope to any patchable destination. 
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Synth|Preset")
	TArray<FEpicSynth1Patch> Patches;