Prompt Audio · FM synth
Bessel
Six-operator FM synth with a free 8x8 matrix and about 15,400 built-in voices
Bessel has six FM operators, and in its 8x8 matrix any operator can modulate any other, feedback and cycles included. A saturator and noise operator and a dual morphing filter operator join the six. It comes with 42 factory presets and 481 built-in banks of about 15,400 voices, and it imports voices and banks in DX7 SysEx format.
- Operators
- 6
- Envelopes
- 9
- Built-in voices
- 15,400
- Effects
- 12
What it does
Any operator modulates any other
The 8x8 matrix allows feedback and cycles. A menu loads any of 32 six-operator algorithms when you want a known starting point.
32 waveforms per operator
Set each operator by ratio or fixed frequency, with detune, offset, velocity and keyboard level scaling. All 32 waveforms are band-limited.
Envelopes with 32 points
Nine multi-breakpoint envelopes have curves per segment, sustain loops, tempo sync and key and velocity scaling.
A filter inside the FM structure
The dual multimode filter operator morphs from low-pass through band-pass to high-pass, in serial or parallel. A saturator and noise operator adds drive and noise.
Imports DX7 SysEx
Load 32-voice bulk dumps or single voices. Bessel converts the algorithms, envelopes, scaling, LFO and pitch envelope.
Arpeggiator, morph square, 12 effects
The 32-step arpeggiator has per-step tie and accent, shuffle and host sync. An XY square blends four corner sounds, and the 12 effects include a tube amp, a cabinet and a talk wah.
Good to know
- Only the 42 factory presets were made for Bessel. The 481 built-in banks come from a public patch archive.
System requirements
- macOS 11 or later
- Apple silicon or Intel Mac
- Formats: AU, VST3, Standalone
- A host that loads Audio Units or VST3 plug-ins, for the plug-in versions
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