*drone is a sound generator based on additive synthesis, also including the concept of vector synthesis.
Four sine oscillators with variable root frequencies can be provided with various harmonic spectra which can be set to change continuously.
The level of the individual oscillators can be modulated by a matrix or by LFOs.
Further documentation can be found in the Max for Live device if Ableton Live's Help View is turned on.
credits: This device was inspired by examples from the book 'Electronic Music and Sound Design - Theory and Practice with Max/MSP' - Volume 1 by Alessandro Cipriani and Maurizio Giri. It contains macros from VirtualSound by Maurizio Giri.