How about a list of speakers that are time and phase coherent? Thiels and what else?

No longer in business but:
Dunlavy Audio Labs
Meadowlark Audio (Actually they are now back in business but I'm not sure they are still doing time/phase coherent speakers).
Quad ESL 63s I believe are time/phase coherent, I seem to remember.

roberjerman,

Are you sure about the 57s being time/phase coherent?

I thought it wasn’t until the 63s that they became time/phase coherent, with the driver made in to delayed concentric rings.

Some people may be fooled into thinking something like the Wilson Speakers would be mentioned in a list like this because they make a big deal of time-coherence with their stepped baffles or sloped design. But they aren’t (as I understand) time/phase coherent/first order designs.

kenjit,

It’s not like you are bringing up a problem that designers of time/phase coherent speakers have never considered. Obviously, any good speaker designer going for time/phase coherence is going to design with those problems in mind.

This is why Thiel, for instance, designed and manufactured their own drivers specifically suited for their goals. Their last midrange driver was a marvel of engineering, and purportedly extended up to around 20kHz with good linearity. (I forget the specs for the tweeter but I remember they were amazing too). Not to mention all the specific engineering put in to specific voice coil designs, motor systems for low distortion, etc.

I’ve owned many speaker designs, and auditioned many, and the Thiel 2.7 and 3.7s are simply the most coherent I’ve ever heard especially in the mids to treble (and exceptional from mids down in to bass). As well as being super smooth.   They were very highly lauded in review after review for incredible clarity, smoothness, neutrality, dynamics etc.  

Whether the time/phase coherence gives an advantage is one thing (I can only say the Thiels image with a specificity and density that I’ve rarely heard before). But the idea that other design parameters must necessarily be sacrificed to achieve it, in terms of the overall performance or sound, doesn’t seem to be true. (As John Atkinson also said after being very impressed when measuring the Thiel 3.7s).

From that speaker design article by JA, on time/phase coherence:

"Many loudspeakers are claimed by their manufacturers' marketing departments to be time-coherent. There are also a number of speakers that have sloped front baffles, implying that they are time-coherent. However, its step response immediately gives you an indication of whether or not a loudspeaker is time-coherent (on the chosen measurement axis).

And almost all loudspeakers are not. Along with false claims of high sensitivity, false claims of time coherence are among the commonest lies in high-end audio."

We're lookin' at you, Wilson Audio.

;-)


Read more at https://www.stereophile.com/content/measuring-loudspeakers-part-two-page-3#v9HvcSQGM5O3Ciq3.99