d-lusion Rubberduck.
d-lusion Rubberduck screenshot

Download Rubberduck Now!

With this bass synthesizer released for Windows 95 in 1996 (way before Propellerheads Rebirth, was available), d-lusion pioneered the market of realtime software synthesizers on standard processors. Roughly based on the the well known TB-303, Rubberduck's synthesis model consists of an oscillator wave with a resonant filter sweep applied to it combined with an efficient hardware sequencer design which resolves in the typical twisted, screaming, bubbling bass sound that is often used in Acid House, Goa Trance, or Techno productions. Rubberduck featured realtime digital resonant dynamic filters, frequency and volume envelope (DCA, DCF), 4 basic waveforms, dual oscillator sound generation (starting with version 2.0), a 224 note sequencer, a drum section where samples could be synchroneous played back, an effect unit (delay/feedback/distortion) and was fully Windows 95 compatible. User feedback was overwhelming, ranging from "the door-bending bass response makes rebirths 303 section sound like a touch tone device" to "fucking brilliant" and the most famous quote which says it all: "it is like fucking a hot hollywood bitch for the price of a corner crack slut". On the other side Rubberduck received impressive press couverage, from "KEYS" to "Future Music".
Potential interesting 3rd party stuff.
BHV Rubberduck.
BHV Rubberduck screenshot Rubberduck was also distributed in the german retail market in 1998 by the Düsseldorf-based puplisher bhv. The package designer was an acid addict for sure!
AIM Rubberduck.
AIM Rubberduck screenshot In the Netherlands and in Belgium, retail-Rubberduck was distributed by AIM. Somewhat less scary package design.
BHV RubberDuck 2000 Pro.
BHV Rubberduck 2000 Pro screenshot A bhv bundle of RubberDuck and DrumStation, just a new GUI was added.