http://www.boss.info/global/gear/261/685
Utilizing the latest in DSP technology, the SYB-5 faithfully reproduces the fat and sharp sound characteristic of classic analog synthesizers. The 11 internal synth sounds are based on combinations of three oscillator waves (Saw, Square, Pulse) and filters that fluctuate according to the envelope and LFO changes. The external pedal input means that bassists can put their foot into the performance by connecting an EV-5 Expression Pedal (sold separately) to control the filter and LFO rate.