Audio Damage Phase Two - Manual (Page 9)

Sweep Generators
The Sweep Generators control the two phase shifters in PhaseTwo. A phase shifter creates its distinct effect by
introducing a series of notches or cancellations in the frequency content of the signal passing through it. The
Sweep Generators move these notches higher and lower in frequency, producing the upward and downward
“whooshing” effect usually associated with phase shifters.
1, 5 The RATE knobs control the speed of the Sweep Generators. Rotating the knobs clockwise increases
the speed. Each knob varies the speed of its sweep generator from 0.1Hz (or one complete sweep every 10
seconds) to 20Hz (20 sweeps every second).
The behaviors of the
RATE knobs are the only respect in which we deliberately made PhaseTwo differ from
the original Bi-Phase. In exploring the Bi-Phase, we found that the Rate knobs do not allow precise control of
the lowest sweep rates. The sweep rate jumps from its lowest frequency of 0.1Hz up to several cycles per
second within only a small range of rotation of the knob. Since we at Audio Damage prefer slower phase-
shifter sweeps, the
RATE controls on PhaseTwo are scaled so that the lower rates are spread over a greater
range of knob rotation than on the Bi-Phase. Hence if you have used a Bi-Phase, you may find that
PhaseTwo’s
RATE knobs have a different “feel” as you rotate them and listen to the sweep rate change. We
also found that while the Bi-Phase manual states that the sweep generator rates range from 0.1Hz to 18Hz,
both our particular Bi-Phase and our simulations created from its schematics show that the upper rate is
approximately 20Hz. We choose 20Hz as the upper limit for PhaseTwo’s sweep generator rates.
2 The RATE CONTROL switch allows you to choose whether Sweep Generator 1’s rate is controlled by
its RATE knob or by the Sweep Control. If the switch is set to MAN, the Sweep Generator’s rate is MANually
controlled by its RATE knob. If it is set to CC, the rate is controlled by the Sweep Control. The Sweep Control
is a hidden control that replaces the function of the Bi-Phase’s optional foot pedal, allowing you to sweep the
frequencies of the phasors and the rate of Sweep Generator 1 with a MIDI controller and/or your host’s
automation features. We’ll describe it in more detail later.
3, 4 The SHAPE switches allow you to choose between two different shapes for each Sweep Generator.
The upper setting chooses a smoothly varying sweep up and down, producing a familiar phase-shifter effect. If
the switch is set to the lower setting, the Sweep Generator jumps from one extreme to the other.
The front-panel graphics of the Bi-Phase depict a sine wave and a square wave above and below the shape