'Phaser' Guitar Fx VST Plugin

This creates a phasing effect. Phasers pass the signal through 'allpass' filters (one or more) and then remix it with itself. An allpass filter passes all frequencies at the same amplitude, but the phase response changes suddenly with frequency. At the allpass centre frequency the phase shift is 90 degrees. If passed though two (or more) then at some point the phase shifted and unphase shifted signals will cancel out producing a dip in the response.

Phase shifters pass the signal though multiple stages and also vary the centre frequency, causing the dips in response to sweep up and down the frequency band.

The centre frequency is settable, and also range (above and below) over which it sweeps. The rate of sweep is settable as is the type of sweep (stepped, smooth with various profiles). Gain control if any of the signal is to be fed back for a stronger response, and dry/wet controls the mix of the phase processed and original signal. In this case the centre frequency is 302Hz, the range is 2.3:1 (therefore the sweep is from 131Hz to 695Hz), the sweep rate is 0.9Hz using the smooth 'multiply' profile, 18% of the signal is fed back, and the processed wet mix is at -6dB.

Specification: