ShadyJ, great feedback. From what most are saying, it seems the 3 speakers mentioned (HB-1, RC-10, and P162) will probably have similar performance. As you said, it would probably take something like the Kipsch to have a truly noticeable forward treble.
Thanks for the honest answer Nixon. I like how you said the RC-10 is a bit more forward and lively; however, not by much. The whole point of changing and "upgrading" is to attempt to have a noticeable improvement.
I have learned what many have said, it is not always about the speaker itself but the environment it is in. The slight concerns I have in my application is that the left speaker has a wall directly behind it, and the right does not. Also, the center speaker is in that fireplace cubby. Is say all this because I wonder if a front ported speaker would perform better. I know the HB1 and RC10 are rear ported, while the Primus is front ported. In the grand scheme of things, I think the final difference would be minimal.
The other concern is the dispersion of the tweeter. From what I have read, the horn tweeters inherently have a narrow spread with the material it plays. I have noticed that with the HB1 horns. The highs also sound a bit muffled at low volumes (they come to life when cranked). I keep asking myself if that is something I can live with. The other concern is that my listening area is a bit broader than the speakers. That causes a slight concern because the highs from the speaker immediately in front is apparent, while the further speaker is not. I know that will be the case in all applications as tweeters yield a narrow field; however, a speaker with better off-axis performance may help.
*The speakers are about 82" apart (6.5ft), while the seating area is about 96" apart (8ft)
I would only know the TRUTH by testing them myself. From the info I gathered from this thread, it seems that it may not be worth it. I just ran a lot of different material through the HB1s. They are impressive speakers, and seem to fit my application pretty well. I was tempted to pull the trigger on the Primus or maybe the RC10s; however, it seems like it may be more trouble than it is worth. I guess ignorance is bliss....sweet sweet HSU HB-1 bliss