Short answer NO! I used to own the 550. With the 550 there is no sound editing, no loading of new sounds and samples via disk. The 550 is a "what you see is what you get" arranger. Not a bad arranger, but limited in some areas.
You could use the 550 as a controller for software applications for sequencing. If you want to use the 550's sounds you'll have to record the 550's sounds as audio tracks with the software.
Squeak
[This message has been edited by squeak_D (edited 08-10-2007).]
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GEAR: Yamaha MOXF-6, Casio MZX-500, Roland Juno-Di, M-Audio Venom, Roland RS-70, Yamaha PSR S700, M-Audio Axiom Pro-61 (Midi Controller). SOFTWARE: Mixcraft-7, PowerTracks Pro Audio 2013, Beat Thang Virtual, Dimension Le.