speakers in a bad room

The room will need some form of acoustical treatment, but I suggest you mate that with a speaker that is designed with narrow dispersion characteristics which you can set up for near field listening. This will probably limit you to single driver or two way speakers.

Onhwy61 gives good advice that had not occured to me. Listening in the nearfield (which really means with you and the speakers forming a near equilateral triangle, about 6-8 feet from the speakers) significantly reduces room effects.

Also having the speakers well away from the rear and side walls (like 2-3 feet) and toed in towards the listening position will all help. Hopefully this will work for you aesthetically .... it doesn't work for my wife so I have a dedicated listening room in the spare bedroom.

Also a highly reflective room will tend to sound bright, and will not tolerate loud music without starting to sound muddled. Hopefully you enjoy listening at moderate volumes.

As for suggestions what is your price range and the rest of your system ?

18 X 24 is a small room??? I guess we live in different economic circles but I know of very few homes that have a room that big.

Set your system up. Use the rug. Talk to Nathan at Eighth Nerve about treating your room. His stuff really works and it is not that expensive in the grand scheme of things. Actually, very cheap for what you get.

Depending on your ceiling height you could actually have a wonderful room. Certainly 18 x 24 dimensions can accommodate all but a couple of the largest speakers out there. The concrete walls are a great asset and will help the bass and add solidity to the sound. Yes, your room is probably bright and reflective right now, but it could have a lot of potential. Its much easier to tame a hard room than try to bring life to a dead one. You'll certainly need room treatment and need to work with knowledgeable people on this. Pile thickness of a rug is very important for its acoustic benefits and character. The wall treatments should be chosen very carefully as well, many of commercial audiophile products do little to help with reflections and if anything do more harm with their coloration. If your ceiling height is 10' or more, you could have an amazing listening room.

Innersound speakers have a narrow radiation pattern which means less reflection off the walls.

This is the direction you need to take.

There may be other speakers that beam Quad ESL 57 maybe?