Since I already had the architecture for a pattern tremolo in hand, I thought: why not do a pattern phaser, too! If you are familiar with a pattern tremolo, then this is the same idea, but with phasing instead–sequenced clock multiples of a phaser, with adjustable waveoform.
The audio modules required for a phaser are considerably more CPU-expensive than those for a tremolo, so certain cuts were made to the number of waveforms (which is fine… the all-pass filters seem to play poorly with a lot of waveforms–you can hear odd clicking/beating sounds from both the square and ramp waveforms–sometimes this is cool, mostly it is kind of annoying).
Still, it preserves the options to select waveform and clock multiple per step, randomize the waveform (albeit with fewer options) and the clock multiple, freeze the sequence, and determine the sequence length.
The signal path is stereo throughout.
Footswitches:
Left — tap tempo
Middle, latching — freeze/unfreeze sequencer; this allows you to stop on a certain step, play, and then reintroduce the sequencer
Front page:
Arrayed across the front page’s first four rows are identical, color-coordinated controls for each step of the pattern, beginning with:
Wave select per step — press one of the three buttons sine, triangle, and square (steps 1 & 2) or ramp (steps 3 & 4) on a given step
Random — randomly selects a waveform per step (note: cannot be applied when the sequencer is frozen or the pattern is limited to one step)
Swing — bipolar control to adjust waveform’s swing per step; this can be used to introduce some interesting variations in sequences using similar clock multiples and waveshapes or to change the sound/rhythm of a given step
Multiplier — this is a value control; I tried to get it to scale as well as I could such that 1/100ths were equival to multiple increements: e.g. a value of .030 = equals a 3x multiple for that step; .100 = a 10x multiple, etc. Select from 1x multiple (synced to tap) to 32x. The scaling is not perfect, but it is fairly accurate.
When the multiplier control is raised above .5, the multiplier per step will be randomly determined from values between 1x and 8x multiples (note: cannot be applied when the sequencer is frozen or the pattern is limited to one step)
Blinky lights — shows the current rate of a given step; when the step is active, it will light up solidly and brightly
Count buttons — three pushbuttons; each corresponds to length of the sequence. When the first is on, the sequence is limited to the first step, when the second is on, two steps; etc.; when none are on, the sequence runs through all four steps
Along the bottom row:
Depth — depth for the phaser
Feedback — increasing this will make the phaser more pronounced; at high feedback it takes on a metallic-flangey quality and can begin to oscillate at extreme settings
Centerpoint — a bipolar control for the centerpoint of the all-pass coefficient; negative values will produce darker, more subdued phasing, positive values will produce brighter, more percussive phasing
Mix — mix!
Sound clip:
0:00-0:24 — Four step pattern with random waveform per step.
0:25-0:48 — Two step, sine pattern alternating between fast and slow multiples.
0:49-1:18 — Two step square pattern with very high rates and very high feedback. This produces a… ring mod, broken radio, formant weirdness… I change it to a four-step sequence midway through and then back to a two-step sequence. The mix is turned down fairly low in this example.
