I think it's not so much backside radiation as delayed reflection from the dipoles. They sound perfectly awful till they get about 4 ft from the wall they're in front of, i.e., = 8msec delayed arrival. I put diffusors to catch sound from behind me (from waveguides in front) and reflect a diffuse arrival about 13msec after the first arrrival, which gives a very natural, 3D presentation (to my probably biased ears, anyway).