Here’s a tutorial of sorts for a subset of the many features of the Hexinverter Mindphaser Complex Oscillator. In this tutorial I walk through five ways to modulate the Carrier oscillator with the Modulation oscillator. This doesn’t cover the fabulous Through-Zero Phase Modulation, but takes a focus on amplitude and ring modulation, linear and exponential frequency modulation, wave folding modulation, and feedback (i.e. wave shape) modulation.
There isn’t a detailed user manual for Mindphaser, but you can watch any number of demonstration videos. Some of those consist of a lot of knob twiddling and button pushing and exclamations of “Wow!” Mindphaser certainly has great sounds, especially when using the TZ Phase Modulation alone or in combination with other modulations. The many variables and their combinations confound any efforts to show them all systematically. So for this “tutorial” I mostly stay away from the Phase Bus. And I don’t review all the features, presuming that you have seen other presentations of those.
To aid in understanding the internal routing and normalizations I drew a diagram.
A couple of things to point out. Both oscillators have full +/-5V output jacks. The Carrier has a fixed square wave output, while the Mod has a pulse with PWM. The Carrier’s sine wave goes through all the wave shaping, including the TZ-PM. The Carrier direct outputs are not affected by any wave shaping. And in particular, the internal waves selected by a slide switch for the default Mod Bus Source are unipolar, i.e. 0 to +5V. Any of the external outs of the Mod VCO can be patched directly to any CV input, including to the Source jack of the Mod bus, replacing the internal selection with a bipolar signal.
I suggest watching the video first and then listening to the following monaural recordings that demonstrate the modulations. Each demo shows one modulation by itself with various modulation depths and frequencies being manually varied.
When listening to this AM, notice that the Carrier frequency (that I called the base frequency in the video) remains constant. At LFO rates you just hear the volume going up and down. At audio modulation rates the modulating frequency comes through. This is a two-quadrant multiplication.
In Ring Modulation, a four-quadrant multiplication, the Carrier frequency is suppressed and we hear both frequencies changing.
Linear FM was performed through the unipolar Mod Bus connection.
Exponential FM takes a patch cord from the Mod oscillator sine out jack to the Exp FM input with its attenuverter.
Wave folding modulation was done with the shape mode switch indicating Yellow. A direct patch from the Mod Sine to the wave folding CV input was used.
Using Yellow shape mode, Feedback does a gentle change between sine and a lower amplitude triangle. This is a subtle modulation when used in isolation.
Feedback shaping in Green mode modulates between a sine and a falling sawtooth. This is pushed only to half depth and so it doesn’t reach into the distortion area.
