soft dome versus hard dome tweeters

Man, the implementation matters a great deal.

Generally speaking, I’ve lost interest in Be tweeters and certainly the B&W diamond tweeters, however the Magico Be based tweeters are really exceptions.

Among the top performers in my mind are soft domes, AMTs and ring radiators, but implementation matters so much. There are garbage AMTs and really amazing ones. Ring radiators have probably the most consistent performance I’ve heard at the cost of narrow dispersion.

Since the beginning of the Be tweeter craze the performance of soft dome's has really gotten superb, flat way past 20 kHz and extremely low energy storage and wide dispersion.  Of course now we also have things like TexTreme which I believe is technically also a soft dome looking to lower the distortion profile even further.

Yes, implementation matters a great deal. It's impossible to "perfectly" isolate all other variables to do a "fair" comparison to these 2 tweeter types. I do have one experience that sticks out - I've heard all the Acora spekears at my local dealer (who sadly is now retiring). The most musical, enjoyable experience I've had is with the smaller SRC-1 tower. That's their ONLY model with a soft dome tweeter - all the others use beryllium!

I specifically listened to SRC-2 (extra woofer, and beryllium tweet) and SRC-1 on the same day. The SRC-2 had the advantage of higher-end VAC gear (much more $$$$), while the SRC-1 was on older (but still very, very high end) VAC. SRC-1 had the advantage of a smaller room, which frankly I probably prefer to the larger room in this shop where the SRC-2 were situated (so that's a big factor). 

Anyways, I really enjoyed the SRC-1 with its non-exotic textile tweet. I'm a die-hard Tannoy fan, but this was one of those moments that had me thinking I could be happy with a non-Tannoy. I still "like" the sound of beryllium (also on some Focals, like Sopra 3), but certainly there's a certain "hardness" to it that I suspect would not fare well for me in the long-run. This character even pervades into the Focal Utopia and Stellia headphones. I've owned the Utopia headphones twice, and sold them. Certainly, the best headphones in my experience all use "soft" diaphragm materials. The issue of ear fatigue is much more severe with headphones.

And that brings me back to my Tannoys, which use very non-exotic (aluminum or aluminum & magnesium alloy) "hard" tweeters. However, the implementation is quite different than most - with either the tulip wave guide or pepperpot horn / compression driver. Careful gear matching is required so the tweeters don't "bite" my ears - more so with the pepperpots. But when properly accommodated, they don't have the hardness of beryllium. And the end result is well worth it, to me :) 

In short, I'm skeptical of exotic "hard" tweeter materials, as far as their contribution to musicality and value to long-term enjoyment.

It’s difficult to be accurate with general statements about any tweeter type, but keeping a potentially long post short, there’s never a free lunch, and every option has pros and cons. Choosing becomes an exercise in identifying your objectives, and managing the potential outcomes....."pick your poison"!

Soft domes tend to be easier to work with, are more forgiving of smaller implementation issues, lesser quality parts, and are generally easier to get pleasant results from, but don’t offer the last word in resolution that metal domes can. I’ve had lots of good results from Audax, Vifa, Morel, Seas, and Dynaudio soft domes.

I’ve never worked with Beryllium (Be) domes, but have lots of experience with Aluminum/Mg domes from Seas and some from Vifa. Metal domes tend to be more revealing on everything in the signal path, from the quality of the caps, resistors, inductors, wire, crossover frequency, crossover slope, phase shift, the source, cables, amplification....just about any contributor you can think of that’s in the path can rear it’s ugly head and come through. But....if you can clean up the entire signal path and get it right, some metal domes can be absolutely extraordinary, and result in next level performance.

Ditto the comments about the Magico Be tweeters. Granted they were hooked up to Convergent amp and preamp, with some superb play back gear, but they sound really good even at fairly high levels.

Thanks @everybody for all of the interesting and informed feedback.

@knotscott 

Soft domes tend to be easier to work with, are more forgiving of smaller implementation issues,

when you guys refer to "smaller implementation" are you referring to the size of the speaker or the size of the room the speaker is to be played in or the size of something else?

It almost sounds as if it might be fair to say that a soft dome speaker is "warmer" sounding?

Is the "ringing" that I have read about related to hard dome speakers an actual true ringing sound?

...Soft domes tend to be easier to work with, are more forgiving of "smaller implementation issues,"

@immatthewj when you guys refer to "smaller implementation" are you referring to the size of the speaker or the size of the room the speaker is to be played in or the size of something else?

No, I was referring to some of the smaller issues of a given implementation of using a given soft dome tweeter...for example: less than ideal crossover points and slopes, cheap inductive resistors with steel leads vs non-inductive wire wound types with copper leads , iron core vs air core/heptalitz/or foil chokes, cheap polyester or electrolytic caps vs really nice metalize polypropylene caps, too much treble output, etc. Nothing is perfect, plus what we think sounds wonderful is subjective, but these are all what I consider fairly common examples of "small implementation issues" of speaker design in general. My meaning is that soft domes just tend to be little bit less critical and more forgiving of many smaller contributors in the sound chain in my experience. That same level of cheaper parts and/or minor design flaws on a metal dome are more likely to sound horrible, while they might sound acceptable with the right soft dome.

Audio terminology for describing the sound of things is always difficult. I’d be more inclined to call soft domes in general as a bit "less revealing", more than "warm sounding", but agree that they’re also less likely to saw your ears off if the design is less than ideal.

I realize that’s there’s plenty of controversy over whether many of those parts differences matter at all, but IME they do, and they’re more likely to show up in a well executed design with any tweeter, but perhaps more so with something like an AL/Mg dome matched to a highly resolving system.

Some may even disagree, but that’s been my experience.

As for the ringing, it's hard to say.  Different materials have different break characteristics, and if a poorly implemented metal tweeter were crossed over too low, driven too hard, or underdamped near the resonant frequency, I suppose it's possible.