Dave Smith Synthesizer Keyboard The Dave Smith Sequential OB-6® is a once-in-a-lifetime collaboration between the two most influential designers in poly synth history, Dave Smith and Tom OberheimThe OB-6 takes the classic bold Tom Oberheim soundwith its true voltage-controlled oscillators, 2-pole filter, and amplifiersand adds modern enhancements such as studio-quality effects, a polyphonic step sequencer, an arpeggiator, and more. No other modern analog poly synth can boast such a pedigree or such a massive, in-your-face sonic signature. The OB-6 sound engine is inspired by Tom's original SEM, the core of his acclaimed 4-voice and 8- voice synthesizers. It features two discrete voltage-controlled oscillators (plus sub-oscillator) per voice with continuously variable waveshapes (sawtooth and variable-width pulse, plus a triangle wave on oscillator 2). The classic Oberheim-inspired 2-pole, state-variable, resonant filter provides low-pass, high-pass, band-pass, and notch functiona