Amboea is a modulated multi-tap/multi-delay effect designed for a specific effect for ambient music. It was designed to delay parts of the sound by different synced periods with modulated feedback to transform pads, arpeggios etc. Into expansive, shifting, panoramic environments.
Acoustic is a simple Acoustic body resonator model, consisting of a first order mass-spring for modeling the helmholtz or 'air' frequency, and a banded waveguide.
Arp4midi combines chris kerry's arpeggiator with contemporary synchronization functions, adding gate offset (e.g. Early or late) host position based sync, and "lobster" ("humanize") functions.