Spendor, PMC, ProAc, ATC- Sonic characteristics and differences?

I haven’t heard Spendor, PMC, or ATC.  But I’ve owned ProAc Response 2 speakers since the day they were introduced in the US 30 years ago.  High quality stands are essential and a lot of attention is needed upstream to keep them from being too forward.  But now that I’ve worked out those issues, I’m not sure how I could improve the sound quality in my modestly sized listening room.  Even at moderate listening levels (mid-70 db), it’s not apparent that the sound is coming from the speakers.  The other side of my room is music, each instrument or singer in their own place.  

About 2 years ago, the surrounds on my speakers finally gave in.  I had no idea what I would have needed to buy to come close to what I’ve been enjoying over those years.  I replaced the mid/woofers rather than try to find something as good or maybe better than the R2’s.  

@nickofwimbledon -Thank you so much for your generous and informative response. This is all very interesting and helpful. Thank you so much for taking the time to share your experience!

@hilde45 -In this instance I am curious to learn more about these four brands in particular. They seem to offer similarly sized traditionally shaped speakers at similar price points and share some of the same background pedigree. And there is not really much out there in the hifi press or online review community on YouTube for these brands.

Much has been written and reviewed about Harbeth. It is arguably one of the speaker brands that is easiest to learn about.

I've owned and used several Tannoy speakers at home and in professional applications through the years and realize Fyne must share some of their characteristics as the engineers for Fyne came from Tannoy.

@sealegs -Thank you so much for sharing your experience! I've often wondered about ProAc and Spendor as compared to Dynaudio. It seems maybe ProAc is slightly more forward or exciting in nature in presentation than the typical Dynaudio sound? 

I don’t audition audio equipment much anymore.  But I have heard Dynaudio minitowers in the past few years and IMO they were not in the same class as ProAc.  Different electronics, in-store demo, etc., but I had no interest in them.

FYI, there is a ProAc Speakers user group on Facebook that gets a reasonable amount of traffic.  

ATC’s roots are in studio monitors. They are considered extremely accurate, and many recording studios rely on them. Their domed midrange driver is legendary and was used by other speaker manufacturers, including Proac, for domestic speakers until ATC stopped supplying other manufacturers.

ATC’s are very accurate and deliver rock-solid imaging, well-defined tonality, and a soundstage that transcends the speakers. They do need power, however.

They also expose mediocre recording quality and some favorite albums may sound unengaging.

Well-recorded piano music sounds very real, with the volume envelope perfect (to me) and the coherence of the harmonics exceptional.

Use the ATC SCM19’s bi-amped with 2 x 140w on each side

I used to own the Proac EBS which used ATC drivers.