@gosta
I wouldn’t call the Harbeth bass "muddy," but it’s definitely not as punchy or dynamic as ATC. - that goes for all the BBC derivatives. What bothered me about the C7s, especially, was their cabinet was very easy to localize in the sound "picture." They didn’t perform the disappearing act very well. The bass was sort of like what I find in stock automotive speakers - overblown in the upper bass. It’s hard to describe, other than to say it sounded like the cone was working a little too hard and the cabinet needed a larger port. That wasn’t the case as much with the SHL5 but it was with the M30s.
The Harbeth midrange is pretty good but they just don’t resolve as much of the music as the competition. They have a brighter treble and upper midrange, which I suspect may be mistaken for greater detail by many listeners. I think the inherent benefits of a plastic cone are lost on Harbeths, because to my ears, they sound like what I associate with ceramic-coated aluminum drivers. It’s as though their goal of creating a very stiff plastic cone resulted in negating the inherent dampening properties of the plastic - so they sound almost like a metal cone. That’s just how I hear them and it goes for the whole range, from the P3s to the M40s.
I’m reluctant to provide these opinions because as you’ve probably noticed, their fanbase is an extremely sensitive and defensive bunch. As I’ve said before, this isn’t to say they’re bad speakers in the grand scheme of things, but I strongly feel they are over-hyped. I can only guess their popularity has to do with their much larger distribution network (in the U.S. anyway), their greater presence at hi-fi shows, and Alan Shaw’s subtle but effective prowess in content marketing. I also have to wonder if some of the audio rags are on their take. Tone Audio wrote a comparison piece where they claimed the C7s were a much better speaker than the Stirling Broadcast SB-88s. I couldn’t have disagreed more with that review. IME and opinion, the reality is quite the opposite. The SB-88s are the better speakers unless one judges them solely on expanse of the soundstage.
Being that you’re accustomed to ATC and Tannoy, I don’t know that you should bother with a BBC type speaker unless you want something a little warmer, in which case I’d recommend either the Grahams or Spendor Classics.