The CHORUS I switch gives a light, airy chorus, the CHORUS II gives a deeper effect. It only has three operating modes: Chorus I, Chorus II, Chorus I + II. It was designed by TC Electronic, le JUNE-60, inspired by the chorus of JUNO-60 Roland. Below is the CHORUS section consisting of three buttons. A DISTORTION knob controls the level of distortion, a TONE knob to filter the distortion (low pass), a LEVEL knob to adjust the distortion output level, and an ON/OFF switch to activate the effect. The DISTORTION section has three settings.
Interesting detail, to the right of each RANGE switch (feet-pipe) is a red LED indicating the activity of the VCO. To the left of this line I find the OSC 4 CONTROL switch which is called OSC 3 CONTROL on the Model D. So, in the OSCILLATOR BANK section there is an additional line named OSCILLATOR-4. For the rest of the synthesis, it's identical to the Model D, with one more oscillator, which I invite you to read here. In the CONTROLLERS section, to the left of Poly D, a MODE selector (MONO, UNI, POLY) and an AUTO DAMP switch (ON/OFF) have been added. The added value of Poly D is of course the fourth VCO and the UNISSON and POLYPHONY modes, Disto and Chorus, the sequencer and the arpeggiator. For more details, I invite you to read the page on the Behringer Model D. I'm not going to go back to the “moog” structure of the Poly D which is like the Model D, that is to say like the minimoog D. Behringer worked out a very nice synth there, as much on the architectural level - well "pumped" it must be said - as of the well polished realization. Behringer added analog effects to the Model D: distortion and chorus, as well as a 32-step arpeggiator and sequencer. Like the Behringer Model D, the Behringer Poly D is an analog with subtractive synthesis but with 4 voices taking up the principle diagram of the minimoog Model D: VCO, VCF, VCA. The novelty comes from the fact that the Poly D has four oscillators, therefore polyphonic 4 voices, and that we can play a chord of four notes. The Poly D models its model up to the control panel which can tilt forwards, adjustable in three positions, for comfortable use. The layout of the pleasantly spaced Poly D buttons takes on the physiognomy of its model ( minimoog model D), even fluted black buttons and black pointers with a plugged aluminum disc above, rocker switches in various colors, a wooden champlat 'back of the keys, all in a seventies seventies look. The body and the front of the Poly D are made of metal, with pretty wooden sides. This time it's not a small table module but indeed a synthesizer with a keyboard of 37 keys of normal sizes (not minis, yuck!).