Ronnie,
Kind of a tough one. You’re right in the middle of needing more speakers because of the size of the room but not having the ability to drive more than a 4 ohm load. The amp you have should be able to drive two pairs of 8 ohms speakers but you may not get enough coverage for the size of the room.
If you know how to wire in series, I suggest 4 pairs of speakers wired in series. The speaker I’d say you got the best bang for the buck is this one. If that’s too much, look at this one.
Brian
Hi! My choir room is 30 x 40. I`m looking at putting ceiling speakers in for 2 reasons. 1) even sound throughout the room and 2) appearance. I have an Alesis GigaMix6FX which is 300 Watts/4 ohms x2 (600 Watts total). Can you recommend in-ceiling speakers that would work with this powered mixer and how many speakers would you suggest? Thanks!
Ronnie