A feedback delay line which allows moving the buffer read position using the switch-and-ramp technique as described by Miller S. Puckette in his Theory and Techniques of Electronic Music book. http://msp.ucsd.edu/techniques/latest/book-html/node63.html
Altering the buffer read position, in order to affect the perceived delay speed/timing, creates a discontinuity in the signal, typically causing unwanted audible artefacts. The switch-and-ramp technique seeks to neutralise these artefacts and allow switching with minimal clicks. See examples.
a signal to be filtered
level of dry signal (default: 1.0)
level of delayed signal (default: 1.0)
seconds to delay signal (default: 1.0)
multiplier for feedback level, affects the length of the feedback tail (default 0.7). limited slightly below 1.0 to avoid speaker damaging mistakes
buffer size (default 20.0)