Dynaudio C1 compared to Harbeth Super HL5 plus?

Yes Pdreher, I do not find the SHL5plus to sound warm too. Though many who are used to lean and bright sounding speakers such as Revels, Magicos etc. will find the Harbeth to sound slightly (or overly) warm. Personally I find the Harbeth to sound just right, natural. Not too warm and not too lean or bright.

Yashu, two of my favorite Harbeth speakers are the C7s and SHL5plus. Some folks like the M30.1 more than the SHL5plus but I find the sound of pianos and guitars to sound muted and dull on the 30.1s although vocals sound very nice. Everyone hears differently so it is best if the listener listens and judge for himself whether the speaker will suit his taste or preference.

It is silly to compare any Harbeth to an Electrostatic speaker. Electrostats are fast and transparent speakers. They dont have any extra bass bloom in general. Harbeth is totally opposite. They are warm and bloomy speakers. They are not really fast or transparent like a ESL at all. An ATC is much more like a Electrostat in that sense. Harbeth is good in other ways. It is warm, forgiving, easy to listen to.

Are Harbeths deficient in bass and high frequency extension?

Nope. 

I've owned them both

the harbeths are much easier to drive than the dynaudios. The harbeths are smoother and have almost no listener fatigue at any volume

the dynaudios need a ton of current and are voiced to play loud t sound their both, yet the dynaudio is a fabulous speaker in its own right

i prefer the harbeth

i now own harbeth 40.1s
they kill anything I have ever owned including Avalon eidolons