Aalto is a semi-modular software synthesizer. Aalto's sound engine lets you create sounds that have been difficult or impossible to make with other softsynths. The heart of Aalto is a Buchla-inspired complex oscillator, with FM, timbre and waveshape controls that enable a wide range of expressive sounds. These sounds are uniquely malleable and alive, in part because they are made with dynamic calculation, not static wavetables.
Aalto is designed as much for sequencing patterns as for playing individual notes. Each voice has a separate, built-in sequencer with a patchable, independently controllable rate and offsets that make it easy to achieve evolving, chaotic textures.
Each voice also includes a lowpass gate module with a vactrol emulation in the control path. The vactrol equation slows down the response to incoming control signals through a complex nonlinear filter. You can turn the vactrol response down to instantaneous, or up to a pronounced ring.