Monotone Bass Synthesizer Introduction The Monotone Bass Synthesizer is a great little monophonic bass synthesizer, designed for seamless integration of Reason Compact projects. Despite its fairly small size, it’s very versatile can produce really fat and punchy bass synth sounds. Monotone features two oscillators, a 24 dB lowpass ladder filter, amp envelope and chorus and delay effects. It also has an LFO and an additional envelope for modulation purposes.