Haas Zone Processor

In 1951 Helmut Haas wrote the paper On the Influence of a Single Echo on the Intelligibility of Speech, describing the psychoacoustic effects of delay on sounds. Since the paper describes short delays, “The Haas Effect” generally refers to delays shorter than 50mS. The Haas Zone Processor enables the effects in this range, including chorus, flange, phase cancellation, doubling, ADT, waveshaping and others.

At the core is a multi-tapped digital Delay Bank largely influenced by vintage studio processors including the Marshall Time Modulator. Tap1 can be switched and swept from less than 1mS up to 20mS. Tap2 is chained from the output of Tap1, adding an additional 1mS-20mS. Tap3 ranges from 9-42mS. In addition to having their own full volume outputs, all 3 delay taps can be blended with the Dry input signal in a voltage controlled mixer.

Also included is a Bandpass filter built from a 2 pole hipass followed by a 2 pole lowpass. Bandwidth can be swept from very narrow all the way to full bandwidth. Frequency can be swept across the full audio range and voltage controlled through a bipolar attenuator.

To the left is a Voltage Controlled Oscillator, similar to the modulation side of a Complex Oscillator. Included is a Triangle, Square and Sawtooth wave that range from 0-10v. The Frequency can sweep from more than 1 minute per cycle all the way up to audio range and tracks volt/octave.
There is an envelope Follower on the input and both it and the triangle output from the Oscillator are normalled to the c.v. inputs on the Delay Time. The output of Tap3 is normalled to the input of the Bandpass filter and the output of the Bandpass filter is normalled to the Feedback In. Through tweaking the Delay Time, Oscillator Frequency and Bandpass Frequency multiple resonance points can be accentuated. The Haas Zone Processor is intended to be used as an effect, inside a patch as waveshaper or as a voice on its own.