Many characteristic effects can be created by configuring the delay in the right way. I will describe how to get some of these effects.

Comb Filtering

For comb filtering, the time needs to be very short, from about 40ms to .1ms. An exponential time control will help in tuning specific pitches. To get the filter to ring, the feedback should be very high, about 90% and above (even above 100%). There should be less compression (or no compression) in the feedback loop. Saturation in the feedback loop can make this effect really stand out.

Flanging

Flanging can be achieved by starting with the comb filter settings above. Modulate the time slowly (1/10th to 2Hz) with a triangle wave from the delay’s minimum time to 10 – 40ms. A low pass filter in the feedback loop can change the timbre of the flange effect.

Multitap Echo

A “tap” is a secondary output of the same delay with a different time. Implementation is fairly simple – add multiple reads of the delay buffer, each with a different delay time. These multiple outputs can create a rhythmic pattern, and each delay output could have a separate gain control. Mix all of the outputs, and be careful not to distort as the taps are summed.

Chorusing

This can be done with one or many taps. The delay times are modulated without much depth around 30ms (so from 29 to 31ms is typical). Modulation is typically done with a sine wave at a low frequency (like the flanger). If multiple taps are used, each one should be modulated by a different phase sine wave, and if possible, output to different spatial locations. Feedback is typically low when chorusing, unless a “seasick” pitch warble is desired.

Loop/Freeze

Delay looping is not the same as a full feature looper, but can be used for some loop applications. Simply set the feedback to 100% (1.0) and the input gain to 0.0, and the sound will be held and repeated.