BEHRINGER PRO 1 ANALOG SYNTH Great care has been taken in engineering the PRO-1, including the true to the original analog circuitry, legendary VCO, VCF and VCA designs, all of which combine to make it easy to recreate the classic sound performance. This highly-focused attention to detail is what gives the PRO-1 its ultra-flexible sound shaping capability, which covers everything from super-fat bass and lead tones to stunning effects – and all the way out to the otherworldly sounds of your imagination.