Diffusion versus absorption behind speakers?

I asked the same question for my soundlab m2's and was advised by rives audio to use diffusion over absorption;I started playing and found both seem to work very well and even hanging rug art behind the panels seemed effective;not really sure what the correct answer really is,but your ear will be the deciding factor.

I had a full "Live end - dead end " set up at one time using Sonnex. I liked it at the time. My present room is 35'x13'x7' and had serious problems. I would also start with bass traps in the corner and go from there. I eventually added 7 more, mostly on the back wall as well as some wool area rugs. the room is still quite live but I can now hear things I never heard before. The amount of detail lost to cancelation due to reflections will astound you. I got mine from Ready Acoustics, who were very helpful, they also will send you a suggested set up if you provide them a picture. They are reasonable and my wife likes the look of their products. No connection, just satisfied customer.

Depends on room, radation of loudspeaker, no right or wrong just whats right for your room system etc.

Thanks everyone for your responses. I am not a novice on this subject. I know treating corners of the room and back wall behind the listening seat with bass traps has beneficial effects to tame room modes. Also treating first reflection points help in imaging. But I have a specific question regarding the front wall. Some use absorption that helps with better pinpoint imaging. Diffusion, I heard, makes the sound stage bigger but images get larger also. I probably will end up with a box speaker and a panel speaker. So I'm trying to to see which front wall acoustic treatment will help both types of speakers. I get the feeling absorption behind dipolar planar speakers may not be a good idea.