The other day I came across this request on one of the audio sites I frequent. "Hi all. I will soon be buying my last speakers. One option I have is a demo pair of Dynaudio Confidence C4 Platinum. But since I have zero experience with the brand, I am curious to know what some of you who heard or own them have to say. Another option I have for about the same price is Harbeth 40.2 Aniversary for the same price...Please feel free to comment. Two very different speakers!"
As you would expect the poster got plenty of replies. Such as "If it's either the Harbeths or the Dynaudios don't rule out the Joseph Audio Perspective 2 Graphene." Or "I own the Harbeth Super HL5 and did own Dynaudio Contour 1.4s. In between I owned the Harbeth C7s."
He continued, "The Dynaudios were a little dark and needed a good amount of juice to come alive." or, "If I had the money to buy the Harbeths, I'd buy Magnepan 3.7s and appropriate amplification." And finally this comment, "Given the differences between the two speakers - make sure that you evaluate them with comparable amps / sources in reasonably similar rooms - while I know that this will be hard - esp. if different dealers etc. You could walk away from the Demos with a strong opinion only to be disappointed with how the speaker works w/ Your amp/source in Your Room...."
After reading the whole comment string only one poster, the last one I quoted, brought up the issue of the room...
Looking at the two loudspeakers the original poster was interested in, the first difference I noticed is the Dynaudios are a much taller, floor-standing loudspeaker while the Harbeths are large bookshelf loudspeakers that will require a stand for most applications. They both use dynamic drivers in a ported enclosure, so in some ways these two loudspeakers are similar - both have basically omni-directional bass response, coupled to a more directional midrange and treble. This usually requires a room that can support the speaker's bass response. It will also require some room treatment to adjust the bass response for optimum linearity. So, while either loudspeaker will sound optimal in a room that has been adjusted for them, they can, in the wrong environment, sound much worse than they should. If you can adjust your room to accommodate the loudspeakers there will be no issues, but if you must place the loudspeakers into a more constricted setting where you can't adequately treat and adjust the room's response, you may never get the sound you heard at the showroom because that sound is a combination of the room and the loudspeakers.
If your room does not allow for the flexibility needed to optimize it for a pair of ported dynamic driver loudspeakers, perhaps another loudspeaker design would work better, such as an open baffle or planar loudspeaker?
In my opinion the best way to approach the search for that "last speaker" is to first look at "your last room" and figure out what kind of loudspeaker it would optimally support. In many rooms you will be better off with something that works with its flaws (all rooms have them) than one that is just too big or the wrong transducer or dispersion pattern for your environment.
So, my answer to the original poster's query would be another question - "Tell me about your room..."