A third sine wave-only oscillator is available on the pitch ('Pich') page. This third oscillator can be configured to either follow oscillator 1 or oscillator 2. When enabled, it will adopt the specified "parent" oscillator's amplitude and pitch. Using O3.Oc ("Osc3 Octv") parameter under 4/Ar, the third oscillator's pitch can be lowered (for a sub-oscillator) or raised by an number of octaves, or can alternatively kept at the same pitch as the parent oscillator.
To make the third oscillator audible, increase or decrease the O3.Lv ("Osc3 LevL") parameter under 3/Ld. Increasing it from 0 will see the third oscillator follow oscillator 1. Decreasing it from 0 will see the third oscillator follow oscillator 2.
The oscillator being a pure sine wave is useful in a number of ways, not just for adding an extra tone to your voice. A sine wave was chosen, because it only contains one harmonic ("the fundamental") at its exact specified frequency. Its addition to your mix will, for starters, therefore be extremely predictable and never muddy your mix. However, this surgical addition (or subtraction!) of one specific frequency is useful for a number of mix and sound shaping techniques.
To take advantage of the third oscillator beyond adding a simple tone at a specific octave detune (indicated by the number) vs the parent pitch, the 4/Ar options further provide the following mode selection;
Just like oscillator 1 and 2, the sub-oscillator's signal is sent to the dynamics block and counts towards any side-chaining, gating or ducking inputs.
The specific attributes of the third oscillator makes it a useful tool to further enhance your synthesized sounds, all without impacting the clarity of your mix.
Create a deeper and richer bass sound by lowering the third oscillator's pitch in relation to oscillator 1 and 2. This generates a sub-bass layer that reinforces the fundamental frequency of the bass sound, adding depth and warmth without overwhelming the mix.
Add subtle harmonic content by raising the third oscillator's pitch by one or more octaves relative to its parent oscillator. This can add a harmonic layer that enhances the overall sound without introducing additional harmonics, keeping the sound clean and pure.
Thickening leads or pads by keeping the third oscillator at the same pitch as its parent oscillator, blending it in subtly (or not so subtly). This can add a sense of fullness and body to lead sounds or pads without cluttering the harmonic spectrum.
Designing unique percussive sounds by using the third oscillator to create a clean and punchy low-end element that complements the percussive attack. An example is the non-noise component of a synthesized (for example 909-like) snare drum.
Set the mode to 'shr' and raise O3.Oc by one or two octaves to feed a pure high sine into the send effects without it appearing in the dry signal. With a long reverb or a feedback delay this produces an octave-up tail that seems to hang above the voice rather than in front of it. Because only a single harmonic enters the effect, the tail stays transparent even at high send levels, whereas a conventional shimmer reverb would smear the entire harmonic spectrum and lose definition.
The 'inv' mode turns the third oscillator into a surgical tool for removing content rather than adding it. Set O3.Oc to 0 to cancel the parent oscillator's fundamental, or to a positive value to cancel a progressively higher harmonic. Thinning a saw wave in this way hollows out its character towards a more reedy, clarinet-like tone, and is a quick route to timbres that would otherwise need a resonant notch filter. Remember that the phase start setting of the parent oscillator (11/A3/Ph.St) is taken into account, so a parent whose phase start is anything other than the default will need that offset accounted for before cancellation is complete.
A busy arrangement often suffers from two or three sounds all claiming the same fundamental. Rather than filtering the offending voice (which colours everything above the cutoff as well) use 'inv' with O3.Oc at 0 to cancel the fundamental of a pad or lead entirely, leaving its upper harmonics intact and giving the bass part unobstructed room underneath. The result retains far more of the original brightness than a high-pass filter set to the same frequency.
Small speakers, phones and laptop drivers cannot reproduce a deep bass fundamental, yet the ear will infer it from the harmonics that remain. Layering the third oscillator one octave above a low bass fundamental provides exactly the harmonic needed for this psychoacoustic effect, so the bass line remains audible on small systems while the true fundamental continues to carry the weight on a full-range system. Because the added tone is a single harmonic, it does not fatten the low-mids in the way that saturation-based bass enhancers do.
The 'clk' mode starts the sine at 90 degrees, at maximum amplitude, producing a discontinuity at note-on that is heard as a click. This can serve as the attack transient of a kick drum, the initial knock of a plucked string, the hammer noise of an electric piano, or the beater of a synthesized wood block. Layered under a soft pad it adds articulation to note onsets that would otherwise disappear in a dense mix. The lower the octave, the more the click reads as a thump rather than a tick.
Reverbs and delays applied to sub-bass content are a common source of muddiness, since the low end is smeared across the tail. Placing the third oscillator in 'dry' mode adds the sub after the send effects, so the low end stays tight and centred while oscillators 1 and 2 continue to be processed. Conversely, 'wet' mode places the third oscillator into the effects chain, which is the better choice when the goal is to have the added tone occupy the same space as the rest of the voice - a pad, for instance, where a separated dry sub would sound disconnected.
Set O3.Oc to a large negative value in 'dry' mode and raise O3.Lv only slightly. The resulting tone sits below the range of pitch perception and is felt more than heard, adding weight to impacts, risers and drones. Keeping it dry ensures the send effects do not build up energy at frequencies that offer no musical information but consume a great deal of headroom.
A pure sine at the fundamental is the easiest signal to tune against. Temporarily raising O3.Lv gives an unambiguous pitch reference for tuning a heavily detuned or noise-laden patch by ear, and for confirming that a patch's perceived pitch matches its notated pitch- the two often diverge once heavy waveshaping is involved. It is also a convenient signal for checking the low-frequency response of a monitoring system before committing to a bass sound.