Patching an oscillator to Maths trigger input and mixing EOR with the main VCO generates sub-harmonics

Sub-harmonic division on Maths: mult the principal oscillator to CH.1 Trigger IN while the main VCO feeds a mixer directly. Set VariResponse to linear, FALL full CCW, then gradually increase RISE time. Maths fires an envelope on each oscillator cycle; as RISE increases, Maths only completes its function every N cycles — generating sub-octaves/divisions. Mix the Maths Signal OUT or EOR with the main VCO through a filter. Adjusting FALL time alters sub-division timing.

Examples

VCO OUT → mult → (main mixer channel) and (CH.1 TRIG IN). Set RISE near 0, FALL near 0. Gradually increase RISE to hear sub-octave emerge. Mix CH.1 Signal OUT with VCO through filter.

Assessment

Why does increasing the RISE time on CH.1 in this patch produce lower-pitched sub-harmonics of the original oscillator?