Hi Joe,
I have recently taken delivery of a setup exactly as you describe. It is called a Clarifier RS501 and consists of 2 x 15watts RMS Satellite speakers and a 30watts RMS Sub-Woofer. Although I have used it several times at my usual venues, last Saturday I played for a large Diamond Wedding Anniversary party in our local very large hall. (120-130 people) This hall has recently had a complete surround sound system put in which includes four speakers at 150 watts each. I was told I could use that if wanted but like you, I was afraid of blowing out my KN7 so I declined the offer and took along the Clarifier which can be used either through the Main Output on the keyboard or through the Phones socket. It was absolutely brilliant. Whilst the guests were eating I played soft background music, whilst the tables were being cleared to make room for dancing, I played singalong music, finally finishing off with dance music covering the 60 years. As the evening got noisier, I changed the reverb to Large Hall and upped the volume which if connected to the Output can be controlled by the keyboard, but you do have to watch the volume a bit more if connected through the Phones socket.
I bought this from a company called BCK so if you want to check it out, their web address is
www.bck.co.uk or, clarifier@bck.co.uk
Hope this helps, it really is worth checking out.
Aud (U.K.)