Fourm 4-Voice Analog Keyboard Synthesizer

Sequential Fourm

Fourm from Sequential is a four voice analog keyboard synthesizer with polyphonic aftertouch, delivering the iconic sound of Prophet-5 voices in an expressive, compact instrument. Built on the same architecture as their legendary Prophet-5, the four voices of Fourm offer exceptional analog tone with plenty of flexibility for diverse sound design. Dual oscillators provide waveform mixing with multiple ways to expand and manipulate timbre, including sync, pulse width, and frequency modulation. Mix oscillators together with a dedicated noise source and feedback path, enabling versatile tones from pointedly percussive to pleasantly melodic. Lush polyphonic chords and powerful unison basses are at your disposal in Fourm, giving you a vast range of tones to explore for virtually any instrumental application.

The onboard 4-pole resonant low pass filter sculpts spectral content while adding warm and rich coloration, with dedicated ADSR envelopes for both amplitude and filter frequency enabling precise note shape control. Other modulation sources include the dedicated LFO, as well as the option to use the second oscillator in LFO mode. Fourm's expressive polyphonic aftertouch keybed provides another source of performative modulation alongside the mod and pitch wheels, allowing you to create nuanced changes per note within a chord for deep expressive potential. Each of these modulation sources can be intuitively routed to a wide range of destinations with the Pro-One inspired modulation section, making complex patches easy to program on the fly. Finally, a powerful multimode arpeggiator is provided, perfect for spiraling arpeggios, random rhythmic melodies, and playable sequences.

For connectivity, Fourm provides all the essentials you need for deep studio or stage integration. A main mono output and a dedicated headphone output get sounds out of the instrument, while a full suite of MIDI input, output, and thru give you plenty of connectivity for interacting with your other devices. Additionally, USB-C connection supports bidirectional MIDI communication with a computer. For even more realtime control, another input is provided for connecting a foot switch or expression pedal. Whether you are just starting out with your first synth and need a versatile source for rich, analog sounds, or a veritable synth veteran looking for a compact unit deserving of a place atop your other keyboards, Fourm delivers legendary Sequential sounds in a form factor fit for any workflow.

Fourm Features

• 4-Voice analog synthesizer with polyphonic aftertouch
• 37-key slim-key keyboard with polyphonic aftertouch for compact expressive potential
• Design inspired by Prophet-5 voice for authentic Sequential sound
• Dual oscillators with simultaneous waveform selection
• Multiple unison modes for powerful monophonic playing
• Oscillator B features LFO ranges
• Oscillator sync capability
• 4-Pole resonant low pass filter with bass compensation
• Oscillator mixer section with noise source and aggressive feedback drive
• 2x ADSR envelopes
• Multimode arpeggiator with glide-per-step sequencer mode
• Multi-wave LFO with S+H
• Pro-One inspired modulation section for intuitive routing
• Main mono output and headphone output
• MIDI 5-Pin DIN input, output, and thru
• USB for bidirectional MIDI
• Footswitch or expression pedal input