INSTRUMENT design – comb-filter (delay) objects
The Ocomb and Ocombi objects are used to build feedback delay lines known as “comb” filters. In fact, the Ocomb and Ocombi objects are essentially just wrappers for the Odelay and Odelayi objects. However, the parameters used to set and control the Ocomb and Ocombi objects are more convenient for many computer-music applications. Comb filter delays are used extensively in room-simulation and reverberation algorihms, and the effect has also figured prominently in many ‘classic computer music pieces.
Ocomb is non-interpolating, so that requests for delay times that translate into a fractional point between two samples will be ‘rounded’ to the nearest sample value. This fractional delaying can happen quite often with dynamically-changing delay lines, which makes Ocombi probably a better choice in those cases. Shifting the delay time of Ocomb may result in audio “glitches” because of this round-off error, but these may be a desirable effect. Ocombi is slightly less efficient because of the interpolation math to calculate a fractional sample-point.
Ocomb and Ocombi replace the older CMIX comb and combset functions.