You’re welcome.
First, I have a low media sideboard between the speakers, and a large flat-screen TV on the wall. Neither are optimal, but with some movement of the sideboard away from the wall, there was a small improvement. For serious listening, I also have a fabric cover for the TV which improves the SQ by reducing reflections.
Secondly, I am not a cable skeptic, but only had one remotely high-end power cable in my system until fairly recently. It is a Shunyata Black mamba CX HC which I bought used some time ago, and use with the amp. The cables that I was using for my DAC and CD transport were a cut above basic, but nothing special. I was also using an Isotek Sirius power strip, with one of their lower-end cords to the wall.
As I was grappling with the bass issue, I spontaneously decided one day to switch the DAC and transport cords just for the hell of it, and lo and behold, the bass tightened up. I really was not expecting such a change, but because it happened, I decided then to upgrade, and bought a used Hijiri Nagomi power cord to use with my DAC. Further improvement noted.
I know that the skeptics will assume confirmation bias, etc., but this was my experience, and I do not consider it to have been subtle. I have no clue how changes in power cords might produce such a change, but they did. I then got a very good deal on an Ansuz Maniz8 X-TC "power distributor", and replaced the Isotek strip with it. I am confident that there was an overall improvement (likely a lowered noise floor, primarily), but can’t say for sure that the bass in particular was affected.
Then, there was the fine-tuning of the speaker placement. After many small changes, I ended up following the basic parameters suggested by Jim Smith in the video on this thread:
and found a noticeable improvement. Basically, instead of an equilateral triangle, Smith suggests that the distance between the speakers should be ~.83 the distance of the tweeters to the ears. So, a bit closer together, and it worked very nicely in my case. Again, I’m not referring only to the bass, but there was clearly improvement in the overall sound. I also fiddled with the toe-in, and ended up with a very good image based on the tweeters aiming roughly at my shoulders. I have noted that FinkTeam tends to toe the KIMs in at shows, as well.
Finally, I have found the integral stands of the KIM to be very well designed, and I don’t believe that there is any vibration between the cabinets and the top of the stands. The spikes are adjustable, which is good, but I found that it is very important, and particularly in terms of bass response, that they be well-tightened. That may seem obvious, but I did some belated, final tightening that caused an audible improvement.
The type of furnishings that you have are also likely to play a role. Sound absorbing fabrics and wood are likely to help mitigate the issue better than glass and other reflective surfaces. When my girlfriend’s (solid side-wall) oak desk was delivered, and placed only about 20" to the left of one of the KIMs, I was worried that it might emphasize the issue. But to the contrary, it actually seemed to help a bit.
Ultimately, a sealed speaker design would likely be best for the type of room limitations that we are discussing. But as happy as I was with the Harbeth that I was using previously, I prefer the KIMs, and am willing to sacrifice optimum playback of poorly recorded albums, given the superb sound and dynamics that they produce with well-recorded ones.