Hi,
I want to jump in here with a different point of view about the upper bass of the RM-40. Over the years I've had speakers with large enclosures, most with transmission lines. The only subwoofer I've had long-term experience with was the Sunfire "True" Mk. II. I don't find the RM-40s too thin in the upper bass, when live un-amplified acoustic music is used as the criterion for judging their sound. On the contrary, I believe almost all amplified music sources, whether from a live presentation, or from reproduced music in the home or in other venues, has a bit too much bass energy in this region. My test for this is whether male vocals remain natural without the prominent chestiness which may make some sound sexier

than they really are. It could be argued that many microphones, especially cardioid types, will exaggerate this chestiness, and therefore, if this exaggeration is in the recordings, it should be reproduced by the speakers. Perhaps so, but I find the lack of this coloration in male vocals to be very refreshing and life-like. Has anyone measured the RM-40s to see if they have a dip in frequency response between 150 and 250 Hz. with the "conventional" 166 Hz. crossover point?
I'm left with two points to ponder. First, I agree with the observation that a subwoofer mated to the RM-40s wouldn't appear to address the upper-bass thinness issue, and whether allowing Brian's excellent woofer to operate a little higher isn't really just adding more coloration to the sound, in part due to the slower transient response of the woofer vs. the ribbon around 200 Hz.
Anyway, I await the observations of those who try the new higher crossover point for the RM-40s.
Enjoy the music!
Curious if these RM40s had the crossovers updated to the ~200Hz+ corner freq? As for adding subs, I'm still thinking the bass thinness is due to lack of presence in the upper bass (like 150-200Hz) region. So, your typical sub will not fill this void. I have the same problem with my current system. I'm thinking that raising the xover freq will definitely bring a more chesty, warmer sound to the mix. I totally agree with your assessment of the rest of the system, however...and I found that it seemed to ...