I recently sold a pair of Harbeth C7ES3XD speakers, the latest model, and they left a strong impression. Having owned more than 20 pairs of speakers, I can confidently say these stand out. They achieve a remarkable balance in the mid/upper frequencies, with zero harshness or fatigue that many other speakers in this range can cause. The imaging is fantastic when paired with sufficient power—I'd recommend at least 50 watts to get the best results, especially in a small to medium-sized room.
The resonance argument is silly. It doesn't matter. I've encountered speakers that struggle with resonance, or have zero, but the Harbeths use it to their advantage somehow.
I decided to part with these speakers mainly due to my challenging room layout, which required frequent repositioning for optimal performance. They also benefit from ample power, and while they worked beautifully with my Supernait 3 (for sale!), I generally prefer tube amplification. I paired them with a Leben amp as well, and the Supernait-Harbeth combination was particularly stunning.
Although this was my first experience with Harbeth, I can see myself revisiting them in the future. While they benefit from a subwoofer for deeper bass, the C7ES3XD has a satisfying, full-bodied sound. Their box size—comparable to the upper torso of an average person—seems to contribute to their weighty, realistic presence. They won’t mimic the depth of a large-scale concert or rock the house with Pink Floyd, but they excel in drawing you into intimate, smaller-scale music venues.