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Coaxial driver experiences and preferences

beefkabob

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Do you have some sort of beefkabob with me? I'm just stating the observations I made with me ears. Not claiming any scientific merit behind these observations though others seem to share similar favorable of opinions of the speakers in discussion. In any case very sorry I offended you with my meaningless vocabulary.

No, I literally meant what I said. That subjective, non-blind descriptions of speakers usually have little to do with measurable truth. So I wondered what if anything your descriptions had to do with truth. I asked mildly. You answered in an unclear way, so I asked more pointedly. What is effortlessness? What are all these adjectives you use? What do they mean in measurable terms?
 

sfdoddsy

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I posted this in another thread, but seems more appropriate here:

I used to have the Thiel CS6 which used a coaxial driver arrangement (tweeter mounted in mid). It was generally effective. However I seemed to notice slight interference issues/suckouts if I moved around.

Later I owned the updated Thiel CS 3.7 flagship and currently have the slightly smaller CS 2.7 using the same newly designed coaxial arrangement.
I found the design Thiel achieved with this coaxial fascinating, especially the fact they managed to "flatten" the mid driver to, among other things, reduce the usual reflection problems with a tweeter mounted in the middle. Image here:

http://4.bp.blogspot.com/-TJzTXgsKcZU/UmQ0zUN6MCI/AAAAAAAABUE/Z76CfkaKjDA/s1600/CS3.7.jpg

Here's Jim Thiel explaining the design at the beginning of this video:


I certainly can't speak to the objective success of the approach. But subjectively both the 3.7 and the 2.7 seem to have hit it out of the park. The mids and highs (and lows!) are the most coherent I've ever heard. I can not "hear out" the tweeter or tell-tale signs of separate drivers or frequency exaggerations at all in the mids/highs and acoustic sounds are just amazingly natural sounding. Image precision and density is the best I've heard anywhere. They also maintain this coherence and even frequency over a seemingly wide range of seating positions. Thiel was a smart dude!

I’ve always found Thiel’s insistence on first order slopes and coax drivers to be somewhat inconsistent. For me the biggest benefit of coax drivers is that they offer consistent radiation in room.Their biggest problem is that the coincident design has variable effects on different frequencies.

My own experiments measured and sounded better with steep slopes, and I suspect that is one of the main reasons many prefer the active LS50 to the passive
 

bigx5murf

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Speaking of, seems Kef went on to 1st order crossovers in their current models.

Looks like the previous tangerine waveguide models were also 1st order. http://noaudiophile.com/KEF_Q300/

I use a pair of Kef Q15 that I restored myself (changed ferrofluid + recap), as my PC speakers. Mine have 2 caps (8uf tweet, 10uf woof), 2 inductors, 2 resistors. I believe this is a 2nd order Butterworth at 3500Hz.
 

thewas

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What only counts are the total acoustic slopes, not just the electrical ones from the crossover, manufacturers like KEF which design their own drivers can make them having themselves already a falling response after the crossover point so not a steep electrical slopes are needed.
 

Frank Dernie

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Matias

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I am a fan of my Thiel CS3.7 and I have no plans to part with mine for a long, long time.
Such a shame no other company continued the Thiel legacy properly...
 

Frank Dernie

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I am a fan of my Thiel CS3.7 and I have no plans to part with mine for a long, long time.
Such a shame no other company continued the Thiel legacy properly...
I see that from your signature.
It seems to me that there are two quite separate types of coaxial unit. One where the mid range is made as a waveguide for the tweeter like KEF and Genelec and others where it very definitely is not, like the Thiels and Piegas.
https://piega.ch/en/products/coax-311
 

bigx5murf

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There's also these, which are just a tweet suspended over the woofer, car audio does this a lot. It's cheap, but works surprisingly well in vintage DCM speakers.
 

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MattHooper

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When you look at the amount of effort in development to which KEF and particularly Genelec go to remove all diffraction inducing ridges and obstructions from their coaxial units one would expect this one would be "diffraction city"

Could be I guess. I dunno. I'm not a speaker designer.

The problem, especially for those of us who don't have a deep technical knowledge of speaker design, is that there are so many opinions. Every speaker company has tested X, Y, Z designs and decided "Y" is best, where another designer has a different conclusion. Same with those with DIY experience. "My experience having designed speakers is that Z is superior." And there will always be a view as to why the design-in-question is "wrong" or "problematic" on technical grounds.

So, I can find all of this interesting to watch the debates and the arguments, but this is also why I ultimately have to just hear a speaker to make up my own mind. Whatever major problems the Thiel coax design may have from one viewpoint, they sure aren't sticking out to my ears. The sound in my room is so coherent from top to bottom, and the sweet spot so wide (and the tone so consistant even from outside the room), that when I audition other speakers they sound more artificial and discombobulated. (Even speakers I otherwise quite like). Even after I auditioned the Kii 3 speakers, when I came home the Thiels just seemed to image with even greater precision and density, and sounded more believable to me.
 

Martigane

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I found this review online that has measurement of different coaxials from Fyne/Kef etc:
https://www.hifi-voice.com/testy-a-recenze/reprosoustavy-podlahove/2365-fyne-audio-f501
https://www.hifi-voice.com/testy-a-recenze/reprosoustavy-podlahove/2484-fyne-audio-f1-12
https://www.hifi-voice.com/testy-a-recenze/reprosoustavy-podlahove/2022-kef-r7

So far I was interesting in the F502; but its on and off axis (or directivity index) does not look too good:
https://www.hifi-voice.com/testy-a-recenze/reprosoustavy-podlahove/2227-fyne-audio-f502
1583648610893.png

Any suggestion for a good coaxial loudspeaker in 1-2.5k range?
So far Kef R3 and F502 look interesting.
 
D

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I found this review online that has measurement of different coaxials from Fyne/Kef etc:
https://www.hifi-voice.com/testy-a-recenze/reprosoustavy-podlahove/2365-fyne-audio-f501
https://www.hifi-voice.com/testy-a-recenze/reprosoustavy-podlahove/2484-fyne-audio-f1-12
https://www.hifi-voice.com/testy-a-recenze/reprosoustavy-podlahove/2022-kef-r7

So far I was interesting in the F502; but its on and off axis (or directivity index) does not look too good:
https://www.hifi-voice.com/testy-a-recenze/reprosoustavy-podlahove/2227-fyne-audio-f502
View attachment 53304

Any suggestion for a good coaxial loudspeaker in 1-2.5k range?
So far Kef R3 and F502 look interesting.

I would highly recommend demoing the Fyne speakers before you buy. I had the book shelf from this series, the F500. Lovely looking speakers which sound clear. I recently borrowed a pair of Revel M106’s and listened to them side by side, the difference was almost embarrassing. The Revel was in a completely different league. So either the Revel is absolutely a top of the class performer or the Fyne’s were always not so great. I must admit the Fyne’s never amazed me with any particular quality, I bought blind as could get them for a very good price. I have n’t heard the other speakers in the series but they use the same parts and tech etc.

I appreciate you’re looking for a coaxial but thought it may be helpful.
 

Martigane

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Thanks for the heads up. Indeed the m106 measures pretty well, but is 3 times the price of the f500 if i recall. F502 with their large 2x8" driver is appealing, cone reaking seems well damped, but frequency response ses a bit ragged
 
D

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Thanks for the heads up. Indeed the m106 measures pretty well, but is 3 times the price of the f500 if i recall. F502 with their large 2x8" driver is appealing, cone reaking seems well damped, but frequency response ses a bit ragged

That’s true, there is a fairly big difference in price, although what I ended up paying for a new pair of M106’s brought them a lot closer so I hadn’t considered that until you said it.

I was actually interested in the F502’s myself before I heard the Revel’s but never got as far as listening to them. Do let us know what you think if you do, as I like the brand and would be interested to hear how the floorstanders perform.
 

oivavoi

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From the new breed of pro coaxial I can recommend the Beyma 12XA30Nd and 15XA38Nd. They don't measure well but they sound very good. It's a diffraction-based tweeter to achieve wider dispersion for a larger sweet spot.

Old comment, but this piqued my interest so I'm bumping it. Care to elaborate? What do you think is the reason they sound good in spite of their measurement?
 

KSTR

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Mostly, the effortless dynamics and the texture detail (some of which might be artificial), apart from the pinpoint yet wide soundstage and quite wide dispersion (due the the diffraction-type of the HF-section). I always compare listening to that kind of coaxials to riding a motorcycle, say, a vintage Harley Davidson in this case. A bit rude at times, but a big joy most of the time, there is a character I can enjoy very much. Whereas a perfect studio monitor like a Neumann KH420 is more like a "precision" touring bike of today. It takes you from A to B as perfect as it gets but alas, not much vibe....
 

Ro808

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Hi. I built a pair of simple wall mounted open baffles using the C18s, crossing to sealed bass units below 300Hz.

Very nice sounding (and decent measurements too).


That's a sensible design.
To prevent the cone from interfering with the tweeter, it is best to avoid low frequency reproduction through a small coaxial.
For larger drivers, this is much less of a problem due to the larger cone area and subsequent limited excursion (required for domestic SPLs).
 

Goodman

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Mostly, the effortless dynamics and the texture detail (some of which might be artificial), apart from the pinpoint yet wide soundstage and quite wide dispersion (due the the diffraction-type of the HF-section). I always compare listening to that kind of coaxials to riding a motorcycle, say, a vintage Harley Davidson in this case. A bit rude at times, but a big joy most of the time, there is a character I can enjoy very much. Whereas a perfect studio monitor like a Neumann KH420 is more like a "precision" touring bike of today. It takes you from A to B as perfect as it gets but alas, not much vibe....
Interesting parallel, Have you found something in between the 2 extremes; Studio monitors are fatiguing. Coaxials have their problems.
 

sfdoddsy

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I think it depends on your listening situation.

As mentioned above, I've built speakers using the very good, very expensive Seas C18 coax using active crossovers and EQ.

I've also owned a few commercial KEF coax speakers (LS50/R3/Reference) which also use very very good drivers. For coax.

Plus I've had long sessions with TAD/Pioneer coax speakers.

I dabbled in coax-land because my listening position and room meant the trade-offs for regular driver alignments were worse than the tradeoffs for coax.

Getting decent horizontal dispersion from a regular TMW isn't exactly easy, but is also fairly well-established. Speakers such as Revel, Genelec, JBL and others do an excellent job.

But good vertical dispersion from a TMW design is much harder.

And if your ears are normally below the level of the tweeter (as mine were) this is easily measurable and audible.

Good coaxes fix this in a way no TMW I've owned or built does. I could stand up or slump and the sound doesn't change.

Unfortunately, that sound (in my experience) isn't quite as good as a really good TMW.

It is hard to build a good small coax. For various technical reasons the tweeter response is never as good as a well-designed TM system.

It is even harder to build a good large coax.

I've listened and measured numerous pro coaxes that try to merge an 8/10/12 driver with a coax tweeter and while some sound very 'exciting' and very 'live' and are very enjoyable to listen to, they don't sound or measure very accurately.

I once spent a hugely enjoyable afternoon listening to Spatial Audio speakers using large pro coax drivers. I almost bought them on the spot because they made everything sound so fun. Until I got home and listened to the same tracks and realised they should sound different.

In my less than humble opinion, the only way to do a good coax is as a three way. The KEF R3 is the gold standard as shown by Amir's measurements. Small mid, very clever and mostly successful technology to overcome the mid/tweeter issues, and crossed to a normal woofer below 300Hz.

You can throw money at the drivers or box or DSP like KEF Reference or Genelec.

But I don't think they'll sound as good as the same amount spent on TMW in the right room.

So whilst I still have the Seas C18 drivers, I no longer use them.

I have two listening spaces in my new house. In the main one I can sit far enough away that the sound of my well-designed TMW speakers (Davone Solos, similar to Revel F208) doesn't change when I slump.

In my upstairs one I have DIY open baffles with ribbon tweeters built specifically so that the tweeters are lower than usual.

As for a direct answer to the query above, you appear to want something that doesn't necessarily adhere to the Harmanesque ideal so beloved here.

I'd give a well-designed open baffle a try.
 
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