Hi Trevor, I have a Bk9 for home use only- especially as it has no external speakers unlike my previous E86! Sorry ex-neighbours..
I have a set of Roland headphones that seem to make the sounds a bit `tinny`?
Having never tried the Bk9 through speakers, I am a little surprised that it doesn`t sound too great, as I would love to hear a big noise.
I think the sound engine is capable , but not really up to say Fantom capability?
I am curious to know whether routing the Bk9 through an Fa would produce the live sound required? That way , one could have the styles and the sound.
Maybe , as Roland are a bit out of the `Arranger` market probably not having sold enough G70 and E80s to continue improvements.
As `Fellwalker` said , the E09 is just as good.
My personal choice of brand is Roland, but I did have a PSR??? keyboard for our daughter which was huge fun and the most incredible Grand piano sounds through headphones at least and very sorry to have lost some of the arrangements when I sold it to make room for the Bk9 - the E86 having become terminal and in the way of the ironing board!
Try looking up Peter Bartmann on Utuub demonstrating the Yamaha Genos- oh my g*d! If it wasn`t for wanting to make my own music I would give up and just listen to him and the Genos. But how much £???
Back to your original question though, I imagine one would require a decent stereo PA system or provide the audience with bluetooth headphones and give the bar staff a break!
Best wishes,
Nicodo