Coaxials - Reality vs. Experience?

Tannoy dual-concentrics blew me away when I first heard them, and basically converted me to a Tannoy owner for life. I presently own 5 pairs! As a young man I actually transitioned over to speakers from high-end headphones; the Tannoy DC’s coherence and musicality, versus multi-driver speakers, is what instantly won me over.

I’ve listened to other high-end conventional speakers as the opportunities arise, and they have certainly gotten a LOT better in the past 10 years IMO. I do quite like Magico S series, and all 3 of the Acora Acoustics models. The Von Schweikert VR-55 Aktive and Focal Sopra 3’s are also quite enjoyable, but by the same token the bigger (and very expensive!) models from both of these makers haven’t really impressed me yet.

It’s been almost 20 years, and Tannoys have become firmly seated as my audiophile "home base", so I’m not sure there’s much room for that to change anymore. But I also recognize Tannoys are not for everyone - you either "get them" or you don’t. Also Tannoy had a couple of models that really sucked, IMO. Also individual units could be miswired (like a set of used Glenair 10 I bought - good god did they sound like sh!t until I rewired them correctly), or may have had a driver wire knocked loose (they use very cheap clips) - early on, the woofer of one of my Canterbury GR’s became disconnected during loud playback (easy fix with a set of pliers)! So if it sounds bad, it may have been caused by one of these issues rather than the design itself!

In your opinion, are they great because they are Tannoy or because they are coaxial?

@erik_squires That’s a good question! Thinking on it, I’ve somehow managed to avoid hearing KEFs and most other coaxials. I have heard Thiel CS7.2, which features a coaxial, but there’s a lot more going on there too besides just the coaxial - unlike most Tannoys, which focus primarily on the coaxial driver.

I certainly liked the CS7.2, but it didn’t do all the Tannoy things I love :)

Coax speakers were very popular in the 50s and 60s but times moved on. Nothing wrong with a modern coax design but I’m not sure they have any sonic improvement over a conventional 2 or 3 way.

@russ69  So much of the audio tech we enjoy today is positively ancient in origin. The moving coil dynamic driver itself is ancient. Maybe you enjoy class D amplification with digital streaming and, I dunno, air blades? Plasma tweeters? Is there any other speaker tech that isn’t ancient? I myself enjoy vacuum tubes, so the fact that something came from the 50s or 60s (or 40s, etc) is of little concern to me. 

I guess class D hybrid and Walsh drivers are as hip as I can get but my point was not the age of the design but that there are successful designs of most all configurations and coax drivers are not a magic tonic.

@russ69 I don’t think anyone in this thread has been pitching it as magic tonic for any and all audiophiles. I specifically disclaimer’d my 1st post with "Tannoys are not for everyone". However this IS a good place for coaxial and dual-concentric aficionados to express what they love about ’em. Which I did :) 

Maybe you could be more specific about the sound qualities you ascribe to concentric drivers.

@tomcy6 For me: Coherent, natural sound with solid & sharp imaging, because the tweeter and mid/woofer covering the critical midrange crossover point act more like a single point source rather than a tweeter and woofer barking at you from different locations. That said, high tech multi-driver speakers like Magico and Acora are getting better at this and seem to be closing the gap, plus the other benefits all that tech & exotic material offers. Tannoy materials are rather pedestrian by comparison. 

The real purpose of a coincident source driver is because of the waveguide affect of placing the tweeter in the center of the bass driver. A waveguide to a tweeter extends the frequency response lower allowing a 2 way to utilize a larger driver for more bass extension and volume while not asking it to operate outside its physical abilities thereby introducing distortion. Andrew Jones mentions this in his description of his speaker. Not really anything new though.

@boostedis How can that be the "real purpose" of a coaxial when you can more easily put a separate tweeter behind a wave guide - no complex coaxial required?

The real purpose of a coaxial seems to be the advantages (whatever those are) granted by the spatial co-location of the main tweeter and mid-woofer. In Tannoys featuring a single dual-concentric driver, this better estimates a coherent "single point source" driver, but with more extended FR compared to single-cone drivers or the complications of huge electrostat panels.

Have you compared Rockport speakers to your Tannoys and if so how did they compare?

@ronboco Unfortunately, I have not, yet - but they look amazing! I’ve always admired pics of their builds.

@russ69 Did you really start this thread with a "times moved on" argument against coaxials and then admitted to using Ohm Walsh’s, a design from the early 1970s? lol

There were many bad coaxials back in the day, where you see tweeters kludgily bolted on in front of a woofer. That's what we've moved on from. Not the excellent Tannoy design (which they got right back in the 1940s and have been refining since then), nor the other sophisticated coaxials we we see in high end audio today.

Definitely, nobody is claiming coax or DC to be a perfect scheme, and in particular Tannoys do not look good in measurements. Fortunately I enjoy music, not measurements!

The Tannoys with a 15" DC (like my Canterbury) are probably pushing that woofer a bit far, asking it to do 1,100 Hz at crossover. They are technically "beaming" at that point but the dispersion of the horn tweeter helps cover for it, somewhat. Within Tannoy fandom you’ll find fans specifically of certain driver sizes, or of the tulip vs. pepperpot wave guides. I love both the 10" and 15", and both in tulip and pepperpot, but they certainly do different things. For some reason I haven’t been enamored by a 12" DC yet; you’d think that would be the good compromise.

As far as Tannoy tulip vs. pepperpot waveguide: pepperpot (usually paired with a single alnico magnet which is VERY expensive) is capable of a more vibrant, lifelike and gorgeous midrange with very fast transients and "startle" factor, but on the flipside its top end can get a bit rough and requires careful system matching to keep this in check! Tulip (dual barium ferrite magnets - this makes the drivers MUCH cheaper) is more even keeled and a great all-around performer, but can’t quite get the midrange exactly as lovely as a good pepperpot.

@prof Prof    100%           it is impossible to hear difference between tweeter location in the center of main driver or couple inches from . This is placebo efffect or good marketing point.LOl

Sure just get a cardboard box and throw a few drivers in there, place them wherever really, what does any of that matter? 😂

closenplay stated,

"To add clarity, concentric is a subset of coaxial. In other words, all concentric drivers are coaxial but not all coaxial drivers are concentric. @erik_squires Pardon the presumption; you are probably referencing most designs intended for the hifi home user, of which most (if not all) are concentric."

I know what "coaxial" means but how are you defining "concentric"? Are you suggesting that two coaxial drivers (i.e. their voice coils) may me mounted at an angle to each other? That they are centered but not perpendicular? Or?

@herbreichert - Not to speak for @closenplay but my interpretation was that he’s focusing on the z-axis (forwards / backwards) alignment. An egregious example of z-axis non-alignment would be in some car stereo drivers, where they (sometimes) clumsily suspended & mount a tweeter in front of a woofer. That’s what I think he was calling out.

But the reality is that none of the coaxials really seem to have perfect z-axis alignment (relative to the 2 drivers’ acoustic centers). Certainly not Tannoys, which mount the tweeters well behind the back of the woofer, coupled through a relatively long waveguide. Tannoy’s brief attempts to time-align the drivers via electrical means were generally regarded a failure. Their pepperpot waveguide drivers at least have phase alignment at the crossover point; not sure about the tulip drivers.

Tannoy chose to call theirs "dual concentric" early on, probably to help distinguish their approach from far less refined coaxial arrangements of the time.