Following up on the success of the popular Virus A, Access unleashed an upgraded model in 1999, the Virus B. The original Virus A had 12-voice polyphony, but the new OS in the Virus B doubles the polyphony from 12- to 24-voices and the oscillators, from 2 to 3 per voice. The new OS also added an enhanced programmable 32-band vocoder. There are now up to 82 simultaneous effects, a retro-phaser (6-stage stereo phaser with 24 filter-poles), chorus/flanger, ring modulator, multiple forms of distortion, an analog boost algorithm, and an envelope follower. Up to five FM (Frequency Modulation) modes are also on-board now instead of the 1 only in the Virus A and many new sounds have been created for this bigger and better version of the Virus.
OS 4.0 was released in late 2000 with even more amazing features! The update is downloadable from Access and comes installed in all new Virus synths to ship after its release. OS 4.0 adds a reverb with advanced features such as pre-delay sync-able to Midi clock. There's also a groove delay, surround sound capability, external effect sends using the individual outputs, an Intelligent Random Patch Generator, sound categories to sort all your patches in a logical order, Direct FX to use your Virus as an effects-processor while maintaining full polyphony, 16 independent arpeggiators with numerous patterns and realtime parameter access, and an advanced distortion module with lo-fi and filter dsp-effects. "Adaptive Control Smoothing" ensures ultra smooth parameter changes.
The KB packs all the guts of the Virus B into a full sized keyboard with 61 velocity and aftertouch sensitive keys. There are also individual and assignable Pitch and Mod wheels. A layout that remains faithful to the module's design make the Virus KB model an excellent dance and electronic music synthesizer for professional quality music and groovy results.