Volca Bass

Bass Synth w/ Sequencer

Aggressive sounds that stand up to the drums; fat sounds that support the rhythm; funky sounds that generate a groove - the volca bass is an analog bassline groove box that has what you need for a wide range of bass lines.
Although simple in structure, the analog sound engine has an unmistakable presence with subtle nuances that cannot be reproduced by a digital simulation; it's a great choice for acid house and many other styles of music. The step sequencer distilled from the Electribe is not only visually intuitive; it's also a powerful way to generate "free form" bass loops that will stimulate your inspiration.

http://www.korg.com/us/products/dj/volca_bass/