Large room fix

I presume, from your question, that significantly treating the room is not a practical option. Still, if you have slap-echo, that really has to be dealt with. The more stuff you put into the room to break up the energy that would otherwise reflect off of hard parallel surfaces, the better. Perhaps a bookcase, some large leafy plants, or a wall tapestry or two?

That being said, a room that's on the "live" side is my preference. I don't like dead rooms.

Now in a large, live room the loudspeaker's power response (summed omnidirectional response) will tend to dominate the percieved tonal balance. So in such rooms, I prefer loudspeakers that have a smooth power response. This implies consistent radiation patterns over most of the spectrum, which is something that horns and dipoles tend to do better than direct-radiator cone-and-dome loudspeakers (although there are exceptions).

If you have a large room where the speakers can be placed fairly far from nearby reflective surfaces, wide-pattern loudspeakers (including dipoles, bipoles and omnis) can work quite well. If you have to place the speakers fairly close to the walls, then a controlled-pattern monopole would probably be the best bet.

I don't think that changing amplification just for your room is called for, but changing speakers may be and a speaker change might in turn call for an amplification change.

Best of luck to you,

Duke
dealer/manufacturer

The simplest fix is to throw down an area rug to absorb some of the reflected sound. Next is to reposition the speakers and where you sit. Portable/temporary room acoustic panels may be the best answer. The bass panels and mid/hi absorbers are not hard to make if you have time and skills and will save you lots of $$$$$$$.

I need to place the speakers very close to the back wall around 8 feet apart. They are far away from the side way though. Can you please give some specific examples of the speakers you would recommend.

Steady now, as others have advised, tweak the room. Avoid thinking of any equipment changes, especially the purchased kind.