Used with BASS_FXGetParameters and BASS_FXSetParameters to retrieve and set the parameters of a phaser effect.

typedef struct {
    float fDryMix;
    float fWetMix;
    float fFeedback;
    float fRate;
    float fRange;
    float fFreq;
    int lChannel;


fDryMix Dry (unaffected) signal mix [-2....+2]
fWetMix Wet (affected) signal mix [-2....+2]
fFeedback Output signal to feed back into input [-1....+1]
fRate Rate of sweep in cycles persecond [0<...<10]
fRange Sweep range inoctaves [0<...<10]
fFreq Base frequency of sweep range [0<..1000]
lChannel The affected channels using BASS_BFX_CHANxxx flags   

Phasers use an internal low frequency oscillator to automatically move notches in the frequency response up and down the frequency spectrum. An important difference between phasing and flanging is that phasers space these notches evenly across the frequency spectrum, while the notches in flanging and chorus are harmonically (musically) related. You don't hear the notches as such (because they are the frequencies that are removed). What you hear is the resulting frequency peaks between these notches. Phasing works by mixing the original signal with one that is phase shifted over the frequency spectrum. For example, a four stage phaser signal (such as this) could be from 0 degrees at 100Hz, shifted to 720 degrees at 5Khz (these extremes are not quite possible practically, but are near enough to explain the effect). This is how the term phase shifter comes about. A 4 stage phaser has 2 notches with bass response, a central peak, and treble response. By using resonance to enhance the central peak, you can get a sound similar to an automatic wah. Using a phaser with lots of stages and setting the resonance high can give a sound similar to flanging, although they are really quite different.

The fDryMix is the volume of input signal & the fWetMix is the volume of delayed signal. The fFeedback sets feedback of phaser. The fRate and fRange control how fast and far the frequency notches move. The fRate is the rate of sweep in cycles per second, fRange is the width of sweep in octaves. And the the fFreq is the base frequency of sweep.


Dry Wet Feedback Rate Range Freq
Phase shift0.999 0.999 0.0 1.04.0100.0
Slow invert phase shift with feedback 0.999 -0.999 -0.6 0.2 6.0 100.0
Basic phase 0.999 0.999 0.0 1.0 4.3 50.0
Phase w/ FB 0.999 0.999 0.6 1.0 4.0 40.0
Med. phase 0.999 0.999 0.0 1.0 7.0 100.0
Fast phase 0.999 0.999 0.0 1.0 7.0 400.0
Invert w/ invert FB 0.999 -0.999 -0.2 1.0 7.0 200.0
Tremolo Wah 0.999 0.999 0.6 1.0 4.0 60.0

See also