I’ve had 6Ks twice. First time bass was overwhelming, second time it was all perfect. Same room. Tweeters and re-cap on the second pair - makes a huge difference on 6Ks as they tend to be quite old by now… Also periodically carefully re-tighten bass drivers - nothing crazy, just nip them up to make sure they’re not loose.

Also important to position well in the room. The second time I played a little more and found more of a sweet spot.