Equilibrium Pyramid


Equilibrium Pyramid

is a triple oscillator specially designed for the production of harmonic drone sounds. It is based on a rather rare synthesis method: Phase Distortion, as it was featured by the Casio CZ series of old. This instrument attempted to emulate subtractive analog synthesizers by digital means, but sounded nevertheless completely different from modern devices that are labeled as Virtual Analog. Especially the filter resonances are much sharper and clearer than those produced by e.g. a modeled ladder filter, and this makes this synthesis method quite capable of producing all those overtone effects that are so much en vogue in Drone Music.

The "triangle"

structure contains push-buttons that let you cycle through the emulated filter types as well as tuning knobs for the three oscillators. These knobs translate to frequency intervals in three different ways:

  • When the Mode Selector in the middle of the triangular structure is set to No Mode, the tuning is measured in cent intervals (100th part of a semitone).
  • When it is set to Chromatic the knobs translate to chromatic steps - these can be fine-tuned via the Menu below.
  • When it is set to any other mode (such as Major or Minor) the knobs translate to diatonic steps - here again the tuning schemes found in the Menu will determine the exact frequencies.

The chords produced in this way will be memorized as one of eight scenes by the Scene Selector below. Automated chord progressions can be realized through an input jack beneath, which will translate signals from 0 to 5 volt.

A left click on the Mode display will re-tune all frequencies of a scene according to the currently displayed translation mode in case this hasn't happened yet.

The "square"

in the middle of the triangle section is actually a 2D-vector display for the resonance and timbre parameters of each oscillator. These parameters are controlled in a rather unique fashion especially suited for drone sounds, providing a lot of inner motion, but nevertheless maintaining a constant volume: All controls are actually balances and will raise a value while lowering another at the same time.

With the resonance parameter this will work as follows:

  • When Reso Y goes towards zero, the resonance of the lower oscillator in the triangle goes up, while the upper oscillators become non-resonant.
  • When Reso X goes towards zero, the resonance of the left hand oscillator in the upper row of the triangle goes up, while the right hand oscillator becomes non-resonant.

The timbre parameter is handled in exactly the same way.

This behavior can be modified by the Even Distribution sliders. These define a percentage of modulation that will be accrued to all oscillators alike, allowing the employment of the classic filter sweep effect.