Yamaha PSR-4500 PortaSound 80s PCM/FM Synthesizer Workstation w/ MIDIYamaha PSR 4500 PortaSound 80s PCM FM Synthesizer Workstation w MIDI Part of the very successful PortaSound line of musical keyboards, the PSR 4500 is an absolute behemoth and one of the line topping models in the PSR range, boasting an insanely huge 100 built in sounds with 100 rhythms, multi voice layering, built in effects, drum machines, music programmer section and a customisable digital synthesizer section. To add a bit of fun to the mix, it