Each Part has two Layers (A and B), and each Layer has a set of synthesis controls.
Each Layer has its own polyphonic Primary Oscillator, which can be set to either Sample Mode (using Soundsources) or Synth Mode (using DSP Waveforms). Because each Layer has its own independent Primary Oscillator, you can mix and match the modes by using two Layers.
Using Omnisphere’s unique Harmonia feature, each Layer can add up to 4 additional oscillators, giving a single Part as many as 10 separate oscillators!
To learn more, please refer to the extensive Oscillator section of the Reference Guide.
NOTE: It isn’t necessary to use both Layers when creating sounds. In fact, very complex sounds can be achieved using only one Layer.