the record spot:I take it you're referring to my post, no you kind of misread, but I phrased it badly - two ports in all, one to the front and the other, as you say, at the back. Still reckon that's one too many given the speaker driver design!
By the way the RS6 only has one bass driver, the other large one is midrange. The effectiveness and effect of bass ports are a matter of debate - the number of ports does not necessarily make a lot of difference to the sound. I would let my ears judge how a speaker performs, rather than acoustics. Acoustics is not an exact science, by any means.