AudioEffect Struct

An AudioEffect struct stores the parameters used by an audio effect. You can change these values to adjust the effect in real-time.

This struct must be created using the audio_effect_create function. The parameters that are available in the struct depend on the type of audio effect that you pass to the function (see AudioEffectType Enum).

NOTE This is a built-in struct, and as such GameMaker has more control over its contents. This means access to its members is limited and some values may change automatically if invalid values were assigned. You may also have to create and destroy this struct through built-in functions provided by GameMaker instead of the new and delete operators.

All structs of this type have a type and bypass property. All other properties are specific to certain types of effects.

Below is a list of struct members depending on the type of effect created.

Reverb (AudioEffectType.Reverb1)

Variable	Type	Description
type	AudioEffectType Enum	A read-only property that stores the type of audio effect stored in this struct. It is set to AudioEffectType.Reverb1 for Reverb.
bypass	Boolean	Whether the effect should be bypassed (ignored).
size	Real	The size of the space [range: 0.0 - 1.0]. Larger sizes mean more reflections and a longer reverberation.
damp	Real	The amount that higher frequencies should be attenuated [range: 0.0 - 1.0].
mix	Real	The proportion of the original/reverberated signal in the output [range: 0.0 - 1.0]. A value of 0.0 gives 100% of the original signal, a value of 1.0 gives 100% of the reverberated signal. A value of 0.5 results in 50% of the original and 50% of the reverberated signal.

Delay (AudioEffectType.Delay)

Variable	Type	Description
type	AudioEffectType Enum	A read-only property that stores the type of audio effect stored in this struct. It is set to AudioEffectType.Delay for Delay.
bypass	Boolean	Whether the effect should be bypassed (ignored).
time	Real	The length of the delay (in seconds).
feedback	Real	The proportion of the delayed signal which is fed back into the delay line [range: 0.0 - 1.0].
mix	Real	The proportion of the original/delayed signal in the output [range: 0.0 - 1.0]. A value of 0.0 gives 100% of the original signal, a value of 1.0 gives 100% the delayed signal. A value of 0.5 results in 50% of the original and 50% of the delayed signal.

Distortion (AudioEffectType.Bitcrusher)

Variable	Type	Description
type	AudioEffectType Enum	A read-only property that stores the type of audio effect stored in this struct. It is set to AudioEffectType.Bitcrusher for Distortion.
bypass	Boolean	Whether the effect should be bypassed (ignored).
gain	Real	The input gain going into the effect. There is a hard clipper (clipping at ±1.0) directly after this stage.
factor	Real	The factor by which the original signal is downsampled [range: 0.0 - 100.0]. This is rounded down to an integer.
resolution	Real	The bit depth at which the signal is resampled [range: 1.0 - 16.0]. This is rounded down to an integer.
mix	Real	The proportion of the original/distorted signal in the output [range: 0.0 - 1.0]. A value of 0.0 gives 100% of the original signal, a value of 1.0 gives 100% the distorted signal. A value of 0.5 results in 50% of the original and 50% of the distorted signal.

LPF (AudioEffectType.LPF2)

Variable	Type	Description
type	AudioEffectType Enum	A read-only property that stores the type of audio effect stored in this struct. It is set to AudioEffectType.LPF2 for LPF.
bypass	Boolean	Whether the effect should be bypassed (ignored).
cutoff	Real	The cutoff frequency of the filter. Frequencies higher than the cutoff will be attenuated.
q	Real	The quality factor of the filter [range: 1.0 - 100.0]. This is a dimensionless parameter which indicates how peaked (in gain) the frequency is around the cutoff. The greater the value, the greater the peak.

HPF (AudioEffectType.HPF2)

Variable	Type	Description
type	AudioEffectType Enum	A read-only property that stores the type of audio effect stored in this struct. It is set to AudioEffectType.HPF2 for HPF.
bypass	Boolean	Whether the effect should be bypassed (ignored).
cutoff	Real	The cutoff frequency of the filter. Frequencies lower than the cutoff will be attenuated.
q	Real	The quality factor of the filter [range: 1.0 - 100.0]. This is a dimensionless parameter which indicates how peaked (in gain) the frequency is around the cutoff. The greater the value, the greater the peak.

Gain (AudioEffectType.Gain)

Variable	Type	Description
type	AudioEffectType Enum	A read-only property that stores the type of audio effect stored in this struct. It is set to AudioEffectType.Gain for Gain.
bypass	Boolean	Whether the effect should be bypassed (ignored).
gain	Real	The gain value applied to the input signal.

Tremolo (AudioEffectType.Tremolo)

Variable	Type	Description
type	AudioEffectType Enum	A read-only property that stores the type of audio effect stored in this struct. It is set to AudioEffectType.Tremolo for Tremolo.
bypass	Boolean	Whether the effect should be bypassed (ignored).
rate	Real	The frequency of the LFO modulating the gain (0.0-20.0 Hz)
intensity	Real	The proportion of the input signal which should be modulated by the LFO (0.0-1.0). Put differently, it is the proportion (or fraction) of the signal's/sample's amplitude that is affected by the LFO.
offset	Real	The proportion of a waveform's period that the right-hand channel's LFO should be offset by compared to the left-hand channel (0.0-1.0) At a value of 0.0 and 1.0 the left-hand and right-hand channel's LFO waveforms coincide (because the shape is periodic, i.e. repeats)
shape	AudioLFOType Enum	The waveform shape that the LFO should output.

EQ (AudioEffectType.EQ)

Variable	Type	Description
type	AudioEffectType Enum	A read-only property that stores the type of audio effect stored in this struct. It is set to AudioEffectType.EQ for EQ.
bypass	Boolean	Whether the effect should be bypassed (ignored).
locut	AudioEffect Struct	A filter of type AudioEffectType.HPF2.
loshelf	AudioEffect Struct	A filter of type AudioEffectType.LoShelf.
eq1	AudioEffect Struct	A filter of type AudioEffectType.PeakEQ.
eq2	AudioEffect Struct	A filter of type AudioEffectType.PeakEQ.
eq3	AudioEffect Struct	A filter of type AudioEffectType.PeakEQ.
eq4	AudioEffect Struct	A filter of type AudioEffectType.PeakEQ.
hishelf	AudioEffect Struct	A filter of type AudioEffectType.HiShelf.
hicut	AudioEffect Struct	A filter of type AudioEffectType.LPF2.

PeakEQ (AudioEffectType.PeakEQ)

Variable	Type	Description
type	AudioEffectType Enum	A read-only property that stores the type of audio effect stored in this struct. It is set to AudioEffectType.PeakEQ for the Peak EQ Filter.
bypass	Boolean	Whether the effect should be bypassed (ignored).
freq	Real	The frequency (in Hz) of the filter [range: 10 - 20,000]. This represents the centre frequency of the peak. NOTE The upper limit is either 20,000 or half of the audio device's sample rate, whichever is lower.
q	Real	The quality factor of the filter [range: 1.0 - 100.0]. This is a dimensionless parameter which narrows the peak created, so that a smaller range of frequencies around the centre frequency are affected. The greater the value, the narrower the peak.
gain	Real	The linear gain applied to the centre frequency [range: 0.0 - inf]. Frequencies around the centre frequency will also have a gain applied, which reduces depending on the quality factor and distance from the centre frequency. A gain lower than 1 represents a decrease in volume.

HiShelf (AudioEffectType.HiShelf)

Variable	Type	Description
type	AudioEffectType Enum	A read-only property that stores the type of audio effect stored in this struct. It is set to AudioEffectType.HiShelf for the HiShelf Filter.
bypass	Boolean	Whether the effect should be bypassed (ignored).
freq	Real	The frequency (in Hz) of the filter [range: 10 - 20,000]. This represents the midpoint of the shelf's slope. Frequencies higher than this value will have a constant gain applied. NOTE The upper limit is either 20,000 or half of the audio device's sample rate, whichever is lower.
q	Real	The quality factor of the filter [range: 1.0 - 100.0]. This is a dimensionless parameter which increases the steepness of the filter's slope, at the cost of some resonance at frequencies around the top of the shelf's slope. The greater the value, the steeper the slope, and the greater the resonance.
gain	Real	The linear gain applied to frequencies in the shelf [range 0.0 - inf]. A gain lower than 1 represents a decrease in volume.

LoShelf (AudioEffectType.LoShelf)

Variable	Type	Description
type	AudioEffectType Enum	A read-only property that stores the type of audio effect stored in this struct. It is set to AudioEffectType.LoShelf for the LoShelf Filter.
bypass	Boolean	Whether the effect should be bypassed (ignored).
freq	Real	The frequency (in Hz) of the filter [range: 10 - 20,000]. This represents the midpoint of the shelf's slope. Frequencies lower than this value will have a constant gain applied. NOTE The upper limit is either 20,000 or half of the audio device's sample rate, whichever is lower.
q	Real	The quality factor of the filter [range: 1.0 - 100.0]. This is a dimensionless parameter which increases the steepness of the filter's slope, at the cost of some resonance at frequencies around the top of the shelf's slope. The greater the value, the steeper the slope, and the greater the resonance.
gain	Real	The linear gain applied to frequencies in the shelf [range 0.0 - inf]. A gain lower than 1 represents a decrease in volume.