Keep in mind that the MSPS (Modular Synthesis Plugin System, aka PLG) boards for the 9000Pro (and many other Yamaha devices, including the SW1000XG pro-quality PCI sound card for PCs, the S-03/30/80 line, the CS6x, the Motif line, the higher-end MU models, etc. etc. etc.) don’t work like other expansion cards for other brands. Theirs are for the most part just ROM memory loaded with more wave samples and presets. MSPS cards, on the other hand, add whole new synthesis and/or effects engines to the unit, enabling it to do whole new types of things it could not do before. Even the two that don’t really add new synthesis methods and do seem to merely add new AWM2 wavetable sounds in ROM(the PLG-150XG and and PLG-150PF boards) are still adding new AWM2 engines (which means more actual polyphony) and effects processors (more reverb, chorus, etc. units that can be assigned, added to the ones the host device already has!).

The others, though, not only add new engines and effects, but also (with the exception of the PLG-150VH) new synthesis methods! The VH board adds vocal harmony to devices that don’t already have it (the 9000pro would not need it, obviously), and may be able to add more harmony voices to those that do. But the really powerful ones are the PLG-150AN (emulates a Yamaha AN1X analog-modelled synthesizer, which in turn emulates the classic Prophet 5, the first mass-produced polyphonic analog synthesizer), the PLG-150DX (emulates the classic Yamaha DX-7 and its successors in the world of eight-voice six-operator FM synthesis), and my favorite, the PLG-150VL (emulates the Yamaha VL series of physically-modelled Virtual Lead synthesizers). Each of these works not by sampling the sounds of the Prophet 5 or DX 7 or real physical lead instruments into AWM2 samples in ROM, but by actually duplicating how those instruments worked! You don’t just get the sounds, you get all the powers (and then some) of those original instruments! The AN board can do frequency (with sync and/or ring mod, etc.) and filter sweeps, LFOs, etc. in real time, just like the original Prophet 5. Unlike the Prophet 5, all of that power can be controlled by MIDI! The DX board can change the frequencies, levels, envelopes, feedback levels, etc. of FM algorithms in real time, just like the original DX-7. Unlike the DX-7, this power is accessible through MIDI!

The VL board is best of all, in my opinion: it simulates the way real physical wind, brass, bowed and plucked strings, and other instruments work, not just duplicating their sounds but the real expressiveness that a professional human player of those instruments can do, variable in real-time under MIDI control! To hear that in action, check this Windows Media sound file out! Listen carefully to the sax throughout the first half and at the ending (especially that last note!), and the cornet-like brass solo that occurs about ¾ of the way through. Listen not only to the sound, but how the sounds change in the middle of notes, just as they would with a human player blowing on the reed or mouthpiece and varying breath pressure, embouchure (lips) shape, etc., and also how the attacks change from note to note depending on how the previous note was played. On the cornet solo, you hear some definite lip-slur going on. These aren’t effects that can be easily done with wavetable samples (not without huge multi-samples with specially-triggered cross-fades [like GigaSampler™], and even then the effect isn’t as real as this)! And keep in mind that my sample file isn’t anywhere near as good as VL can get. For one thing, what you’re hearing isn’t a 9000pro or other piece of high-end Yamaha gear with a VL board plugged in. It’s my PC’s $15 sound card with a Yamaha YMF724 chipset that has cheap low-quality implementations of basic sub-Level 1 XG and VL! The same MIDI stream would sound better on a 9000pro with PLG-150 VL installed. Better yet, I’d love to tweak it to use the 9000’s own Cool!, Sweet!, Live!, etc. voices for the backup instruments instead of the Level 1 XG voices it’s using now.