> Step by step

5. Understanding Vacuum Pro’s oscillators

1 The two analogue-style oscillators are found in the VTO One and Two sections. Instead of having fixed waveforms, the Shape knob is continuously variable: turn it from left to right to smoothly fade between Triangle, Sawtooth and Pulse. The latter range of motion sweeps the Pulse wave’s width, creating – yep, you guessed it – pulse width modulation! 2 This Shape dial is a prime candidate for automatic sweeping, hence both oscillators featuring an Env 2 to Shape knob. Twisting this sets the amount by which Envelope 2 modulates Shape. Just like classic 70s and 80s synths, octave Range tuning is set in feet via the stepped knob, with a Fine dial for finer tuning in cents. 3 If you want thick, supersaw-style timbres, flip the Quad switch to activate four-voice unison, then Detune the voices for thickness. Unlike the Roland JP-8000’s supersaw, however, this effect works on all the waveforms, not just the saw. 4 Both oscillators house a single-cycle delay line, dialled in with the Delay Time and Delay Amount controls. This creates interesting timbral variation, which AIR say is useful for “simulating the electro-acoustical feedback that occurs when playing instruments such as electric guitar.” This is ‘free-running’ by default, but when Re-Pitch is activated, the delay is instantly reset. 5 Flip VTO Two’s Sync Mode switch to the central Start Phase position. This syncs the phase of both oscillators, so both restart at identical points in the waveform over each new note. Set Sync Mode to Full for classic hard sync sounds. When oscillator one restarts its wave cycle, oscillator two will also restart. Wiggling or modulating oscillator two’s pitch now creates that well-loved ‘pow’!