Need to buy a good monitor, suggestions please?

I bought a used one today and it turned out to be a waste, I'm very frustrated! I live in a 2 bedroom apartment and am looking for a monitor (sound only, not one with a camera) that is not constantly crackling. Interference is a problem because I live in such close proximity to other people, but I also need a good range of distance between the monitor and the receiver. Any suggestions? Thanks in advance.