ABSTRACT
The most interesting kinds of audio effects, from both listening and engineering standpoints, are the modulated delay effects. They include the chorus, flanger, and vibrato; additionally, modulated delays are also found in some reverb algorithms. These time-varying filters are actually quite sophisticated and fun to implement. The flanger effect gets its name from the original analog method of running two tape machines slightly out of sync with each other by placing a thumb on the flange of one machine’s reel and applying pressure to slow down the tape ever so slightly. The chorus effect is usually designed as a stereo effect. Its intended use is that of simulating multiple musicians or of simulating recording the same musical part many times. The modulated delay produces the timing shifts that occur in both situations. Manufacturers tend to really go out of their way to differentiate the chorus effect in the marketplace.
