For keyboards, the SoloAmp features a 1/4 inch stereo (TRS) Aux Input which mixes the signals to mono when amplified.
The Monitor Input may also be used an another audio input, just like the Aux Input.
User manual can be downloaded from the Fishman site.
According to one of Jack Campbell's postings on the Acoustic Guitar Forum:
"...to cut through the technicalities, in reality, in a small club environment of, say, 100+ capacity or so, Fishman's product should sound better for guitar + vocal than the much more expensive Bose L1 -- even with my grumbling. Why?
I am familiar with the active feedback servo bass augmentation scheme they've implemented with these truly terrific 4-inch drivers. Believe me, the bottom of that fat acoustic sound we all love is there in a way an L1 cannot produce, even with a couple of their cute little "bass" cabinets. Other applications/instruments, I can't say. But, for the specific acoustic player/singer this thing was designed for, the Fishman product is better, theoretically and in practice.
No. I haven't heard one, but I can close my eyes and 'hear' the result of the technology approach they've implemented. There's no way it doesn't stuff the Bose for this usage."
Michael