Norman,
I am using two Yamaha HS80M studio monitors as I use Pianoteq in my project studio. My audio interface is a Focusrite Scarlett 18i20. Latency is around 2 ms, so undetectable to me, at sample rate of 48000 Hz and buffer size of 88 samples and max polyphony of 256. Running on a PC I built 12 years ago (2007). The PC has an Intel Xeon X5675 overclocked to 4.0 GHz and 24 gig of ram. Pianoteq sounds fantastic on this combination.
On another note, I do have a sound system in my basement that I have been considering moving upstairs into my project studio area. It consist of two QSC K12.2 and EV Sub. I'm sure that Pianoteq would sound great through this system, but I have not auditioned it as of yet, but even on the most modest of settings, this would be LOUD! Should I decide to do it, I'll report the results.
@Groove On - QSC makes killer speakers!
If all things are possible, then it follows that it is possible for something to be impossible.