A continually falling lowpass filter sweep built on an illusion, the Infinitely Descending Shepard Filter breathes movement into a sound without the abrupt annoyance of that movement hitting an end or ricocheting back garishly. On the other hand, it has the controls to push it out of subtlety into the realm of shimmering vibrations and then viscous lasers. It can be modulated freely for dynamic behaviors that don’t exactly sound like one effect or another. It’s perfect for those times where you’d like to use a lowpass filter, but want a more complex though subtle result that can be cv controlled into occasional drama.
At default settings, the illusion is optimized and slight adjustment based on source material can help make the ear convinced that the filter is somehow closing without end. Of course, it is merely an illusion and the controls allow you to liberally leave the realm of believability to enable the complex results of shifting resonances navigating movable ranges amid growing and shrinking summits. Connect the “top” control to an envelope generator to track playing with a charismatic “w”, speed up the delta control for something like tape wobble or chorus but not, raise the resonances to bring the sound of breath into a phrase, and make use of the bottom-most envelope and pitch cv outs to coordinate it with oscillators producing Shepard tones that sound like they are endlessly lowering in pitch.
Try the Infinitely Descending Shepard Filter if you’re looking for excitement out of a lowpass, if you like a good sweep but not the abrupt end or rebound, if you want an effect that smoothly transitions from acting like a filter to acting like a chorus/flanger, if you want some new techniques for sound design, or if you just want to hear something new.