The M1 Plus 1 by InVision Interactive is an M1 with 4 megs of additional Multisound waveform data. These are not the same 4 megs of additional Multisounds that Korg put in the M1 EX/M1R EX and T-Series. These Multi's were custom made by InVision and were sold as a new M1 Plus 1 keyboard and as an M1 upgrade. The Plus 1's came with a factory sound card that offered 100 Combinations & 100 Programs based on the new Multisounds.
The Multisounds are quite good... certainly on par with Korg's. Although there are 2 electric pianos, surprisingly there isn't an acoustic piano. The guitars are standouts. The 46 new Multisounds and 45 new Drum Sounds increase the M1's total to 146 Internal Multisounds and 90 Internal Drum Sounds.
The only outward indication that an M1 is an M1 Plus 1 is a sticker that was placed on the synth. Over time that sticker may have been lost or removed.
The Plus 1 Manual, Factory Files, and Demo MP3's are included as part of the Plus 1 Pack.
