Quadraverb 20k

Quadraverb 20k
Released 1989 -

The Quadraverb is a very flexible and controllable multi-effects unit with EQ, reverb, delay, resonator, flanger, phaser, ring modulation etc.
It has midi control; 6 selectable realtime controllers based on which effects you have running in that patch.

The presets on the Quad are very good quality and inspiring to flick through.
It has flexible routing options and plenty ways to customize the sound.
The resonator has 6 channels so you can produce some great pitched sounds with that.


There are 4 basic effects available. They are reverb, delay, pitch shifting, and EQ. In the "QuadMode", you can have all 4 of these at work at the same time, and you have individual controls over each effect. There are several types of reverbs, several types of delays, several types of pitch shifting, and several types of equalizers to choose from.
The reverb department offers 5 types of reverb: Room, Chamber, Hall, Plate, and Reverse. The delay section of the QUADRAVERB offers 3 types of delays to choose from.
They are Ping Pong Delay, Stereo Delay, and Mono Delay. Maximum delay time is 1.5 seconds in the Mono mode.
In the Stereo and Ping Pong modes, each channel can have up to 750 milliseconds of delay. The Ping Pong delay bounces the output back and forth between the left and right channels. Delay time and feedback are variable for each delay. The 1.5 second delay time is a lot of delay for this little box, and it's very clean.


The Pitch Change function is used to create chorusing, flanging, phase shifting, and to detune the input. It is also used to create the common Leslie effect.

The EQ section is quite impressive.
There are 3 EQ's to choose from: 3 Band Parametric, 5 Band Parametric, and 11 Band Graphic. In both parametric EQ's, the middle bands are fully parametric in that you can also adjust bandwidth, while the high and low bands are shelving type equalizers. If that means little to you, just know that the equalizers in this unit could stand alone as a nice little digital equalizer. Test drive


Demo Quadraverb 20k standard patches

QUADRAVERB ( See more in Manual )

The Alesis QuadraVerb is a 16Hz-20kHz bandwidth stereo programmable effects box with four digital effects (EQ, Pitch Change, Delay, Reverb). The effects can be used in parallel or in serial (or a combination). Specs say the dynamic range is 85dB, less than .1% distortion. Processor speed is 24 MIPS (no Z80 in this baby!). Conversion scheme is 16-bit linear PCM. It's fully MIDI-fied.

Some features:

  • Touch sensitive (multi-speed!) programming buttons. Many have integral LED so you know what mode you're in. If you press harder you move the parameter faster.
  • 2x16 character LCD display.
  • Stores 100 programs. Comes with 90 (in ROM) that you can overlay into the RAM. At any time you can recall one or all the ROM programs into RAM.
  • Real-time control of 8 simultaneous parameters via MIDI (you pick the controller type and the parameter it controls).
  • All functions, parameters and volume levels are programmable per program.
  • Stereo In/Out (via four 1/4 inch jacks).
  • Effect bypass jack on the back (as well as a button on the front).
  • You can name your programs (up to 14 characters).


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