ShiftDelay - Frequency Shifter w/ Delayed Feedback [Befaco Lich]


A patch for the Befaco Lich/Rebel Tech OWL that combines a wide-range frequency shifter with a delayed internal feedback path.

This is a pretty straight forward effect, tailored to the way I like to combine frequency shifters with delays. Everything you need to make trippy, spiraling washes of sound that will make your head feel like it’s being twisted in half.


Befaco Lich, Rebel Tech OWL platform, Pure Data



The Left and Right Inputs are mixed down into a single, mono input. The Left input is also normalled to the Right, so it’s best to use the Right input when using a single source, leaving the Left Input available for a second source or non-delayed feedback.

Knob A controls the amount of frequency shift. The up-shifted signal comes out of the Left input, while the down-shifted signal comes out of the Right output.

In the default mode, the maximum amount of frequency shift is a little over 4,000 Hz.

Button 1 switches to low-frequency mode, indicated by the Gate Out LED. This is better for stereo phasing effects and has a maximum range of 9 Hz.

Knob C controls the amount of feedback from the up-shifted signal.

Knob D controls the amount of feedback from the down-shifted signal.

Both signals can be fed back together to create more complex frequency mixing through the feedback loop.

Knob B controls the delay time of the feedback. This only delays the feedback, and not the initial, shifted signal, so it is only audible when feedback is active.

Button 2 will set the clock rate of the delay, defining its maximum time. The delay does not lock to divisions or multiplications of that time.

The absolute maximum delay time is 2 seconds, and the minimum is around 2 milliseconds.

CV Outs 1 and 2 output the sine and cosine oscillators that drive the frequency shifter. These are unipolar and work best at sub-audio rate.


v1.0.0 - OWL Patch Library – Rebel Technology