de la Mancha recently released subatomic, a very simple sub-bass drum-synth, generating a pure sine wave for that deep sub-kick sound when played a couple of octaves below middle C.

Features:

• Pure sinewave oscillator.
• Volume decay envelope.
• Pitch decay envelope.
• Variable pitch drop.
• 6 different vol / pitch decay shapes.
• Drum or synth mode.
• All controls have MIDI CCs assigned.

subatomic is free and functions as a VST instrument on Windows.