The PerFOURmer is a true analog synthesizer, providing a nearly unlimited diversity of basses, leads, pads and effect sounds through its incredibly flexible sound generation circuitry and its easy user interface. In addition, the PerFOURmer can be used as a complex filterbank with its 6 filter inputs!

Even though the PerFOURmer is not a modular system, you can configure its structure as a semi-modular. The basic concept is reminiscent of classic synthesizers like the Oberheim 4-Voice or the Korg MONO/POLY. The PerFOURmer consists of four voices. Each of them is a completely separate synthesizer which can be played and tweaked individually . You can link the synthesizer channels in any combination with each other and play them in 3 modes.

Check out these :

Synthesizer Channels

The PerFOURmer's four synthesizer channels are identical and have the following structure:

• One VCO with six waveforms, which are divided into two different octaves and a noise generator which produces white noise. The pitch can be adjusted smoothly in a range of /- 13 halftones.
• A 4-pole lowpass filter with resonance and variable keytrack.
• A fast ADSR envelope that can modulate the VCA and VCF.
• An LFO with four waveforms which modulates the VCO frequency and the CUTOFF frequency, as well as the VCA.
• One VCA that can be modulated by the ADSR envelope, a fixed GATE envelope or the LFO.

FM
The synthesizer channels 1 to 3 can function as modulator for their neighbouring synthesizer channel. For example, synthesizer 1 can modulate the VCO frequency and the CUTOFF frequency of synthesizer 2. Or synthesizer 2 can modulate synthesizer 3, etc.
The modulation intensity can be adjusted separately for VCO and VCF.

MODES
All four synthesizer channels can be linked in arbitrary fashion and can be used in one of the following three modes:

• UNISON: All combined channels work as one monophonic synthesizer.
• DUOPHONIC: This mode separates the PERFOURMER into a two-voice synthesizer. Synthesizer 1 and 2 are voice no. one and synthesizer 3 and 4 work as voice no. two.
• POLYPHONIC: All combined channels work as a polyphonic synth.
  
  

Depending on the selected mode and in which way the synthesizer channels are combined, the PERFOURMER can be used as a fat monophonic synthesizer with 4 oscillators, 4 filters, 4 VCAs, etc., but also as a two, three, or four voice polyphonic synthesizer .
All synthesizer channels, that aren't combined with any other, work as simple monophonic synthesizers.

PERFOURMER as filterbank
The PERFOURMER has six filter inputs.
There is one filter input per channel. The input signal will be added to the oscillator's signal of the respective channel.
On the rear panel of the PERFOURMER are two more inputs that are routed in parallel to all four synthesizer channels and which can be used alternatively to the oscillators' signal.
The CUTOFF frequencies of the single synthesizer channels can be controlled by MIDI.

Connecting Features
As well as the filter inputs, there are individual outputs per channel that can also be used as a channel insert. It's easy to connect the PERFOURMER to other equipment! It's also possible to tap the unprocessed VCO signal from each synth channel.
You can increase the sonic possibilities of the PERFOURMER by "internal patching" between the channels. For example, you can create a synthesizer that consists of two PERFOURMER channels with two envelope generators and LFOs. It's also possible to double the slope of the filters by connecting two of them in a row.

The PERFOURMER can be controlled by MIDI, and optionally can be equipped with four CV/GATE inputs (1V/octave).