Getting Started
Top Toolbar and Preset Browser
Panel View Mode
Oscillators
Mix
Control Oscillator
Filter
Envelope Generators
Output
Keyboard Panel and Voice Modes
Keyboard Pressure
Scale Keyboard
Arpeggiator
Effects
MIDI Controllers Setup and the MIDI Tab
QWERTY Musical Typing Keyboard (MTK)
Settings

This is a simple mixer for combining the two oscillators and noise source prior to the Filter section.
Osc.1- Sets the audio level of Oscillator 1.
Osc.2- Sets the audio level of Oscillator 2.
Noise Signal- Sets the audio level Yellowjacket's white noise generator. For those not familiar with white noise, it's a non-pitched hissing sound where all frequencies across the frequency spectrum are represented equally.
Depending on filter settings, white noise is useful for wind, cymbals, radio hiss, and most importantly, explosions, which according Devo, leave us feeling good.