Knaster

Das Ekdahl Quad Massager

The Ekdahl Quad Massager is now in production, the price is $450 per unit!

The Ekdahl Quad Massager is a quad VCA, joystick-controlled mixer / quadrophonic panner for Audio or CV. It comes with a voltage-controlled quadrature sine LFO and no less than 18 x 1/4" ins and outs.

In short, the Ekdahl Quad Massager can be used to "move" a signal on a 2-dimensional surface, giving the effect of quadrophonic panning. In reality, the joystick position only sets the volume of the four outputs. At center position all outputs are at their maximum output volume, the further the joystick moves from the center, the less the amplitude of the opposed outputs of the travel.

Each output is controlled by a VCA, each VCA has one signal input, one signal output and one CV input. If connected, the direct CV input breaks the connection to the joystick and LFO routing so that the VCA can be used as stand-alone. The Ekdahl Quad Massager also has CV inputs for both the X and Y axis, serving the same function as the joystick movements.

The Ekdahl Quad Massager is equipped with a voltage-controlled quadrature LFO that can give both sine and cosine outputs. Traditionally, the LFO is used to move the sound in circular or elliptical patterns as well as back and forth along either the X or Y axis. The LFO also has two CV outputs (Sine / Cosine) and one CV input (Speed). The X and Y axises CV input goes full range on +/-2.5V, the direct VCA CV inputs reacts to 0-5V.

Some hookup and usage examples;

Example 1 - Setup for quadrophonic panning from a monophonic source

VCA A In - whatever sound you wanna pan
VCA A Out - Left front speaker
VCA B Out - Right front speaker
VCA C Out - Left rear speaker
VCA D Out - Right rear speaker
Combination Out - subwoofer (optional)

Use:
Manual panning: set the "cosine to y" knob to 0 and the "sine to x" knob to 0 and move the joystick around.
Automatic panning: to have automatic panning controlled by the internal LFO, set for example the "cosine to y" knob to 25% and the "sine to x" knob to 25% and set the "LFO Speed" knob to 25% - this will create circular panning. By changing the "cosine to y" knob and "sine to x" knob to different values from eachother, eliptical panning movements will result. By setting either knob to 0, panning will only happen either left-to-right or front-to-back.

Note about patching: by putting an audio cable into the "VCA A In" jack and leaving the "VCA B In", "VCA C In" and "VCA D In" jack disconnected, the audio from the "VCA A In" jack will automatically be connected to the other inputs - it's like if you had four cables, from the same source going to the four inputs. The way it works is quite simple: audio from "VCA A In" goes to "VCA B In" which in turn goes to "VCA C in" which then goes to "VCA D In", this means that if you connect two sources, one to "VCA A In" and one to "VCA C In", it works like this:
VCA A In -> VCA B In and VCA C In -> VCA D In

Example 2 - Setup for quadrophonic panning from a stereo source

VCA A In - Audio source left
VCA C In - Audio source right
VCA A Out - Left front
VCA B Out - Left rear
VCA C Out - Right front
VCA D Out - Right rear
Combination Out - subwoofer (optional)

This setup might seem unintuitive to some.

Example 3 - Setup for mixing four audio sources to one monophonic output

VCA A In - Audio source 1
VCA B In - Audio source 2
VCA C In - Audio source 3
VCA D In - Audio source 4
Combination Out - to your amp, mixer, stereo, whatever you got

Example 4 - Setup for having one dedicated sound per speaker in a quadrophonic system, using the joystick as a quadrophonic volume control

VCA A In - Audio source 1
VCA B In - Audio source 2
VCA C In - Audio source 3
VCA D In - Audio source 4
VCA A Out - Speaker 1
VCA B Out - Speaker 2
VCA C Out - Speaker 3
VCA D Out - Speaker 4

Example 5 - Setup for using any or all of the VCAs as a stand-alone unit

Inserting a cable into any of the "VCA [X] CV In" will disconnect the VCA from the joystick action and make it work as a standalone VCA.

VCA A In - Audio source
VCA A Out - To your amp, mixer etc.
VCA A CV In - To your CV-source (ADSR, LFO etc.)

Example 6 - Setup for using any or all of the VCAs as a ringmodulator

Note: This requires the "carrier audio" to be a very loud signal like that of a modular synthesizer, a preamp could be used to bring a line-level signal to the desired volume. This does not result in "true" ring-modulation but is close enough and sounds awesome, no complaining.

VCA A In - Audio source to be ring-modulated
VCA A CV In - Audio source that is the "carrier audio", that controls the modulation
VCA A Out - To your amp, mixer etc.