Steve Mowry says in the article "The Whole Truth About Beryllium Diaphragms: -
"For a given geometry the first bending (break-up) frequency is proportional to the material Speed Of Sound, where the speed of sound within a material is defined as the square root of the Youngs Modulus divided by the Mass Density, (m/s); the higher the better. However, the Mass of the diaphragm must also be considered. Then the ratio of the Speed Of Sound to the Mass Density can be used as the materials acoustic figure of merit, (m4/kg/s); the higher the better."
After that he shows values of "Acoustic Figure of Merit" for different material (higher the better)in m4/kg/s
Berillum - 6.97
Diamond - 4.92
Aluminum - 1.86
Titanium - 1.13
Steel - 0.63
How come you didn't include camel hair tweeters in you list of soft dome materials?
I think you just P**** Off quite a few speaker companies. Looks like you just cracked the secret industry list price multiplier formula.
Something I said in my post that offended you? Do you really have to respond in such a rude manner to a normal question I asked?
That was very interesting. Thanks for the post. I would have thought the value for titanium would have been higher than aluminum.
Do you have any info on soft domes? I am wondering what the difference in materials between soft domes and a textile dome? Or perhaps a textile is considered a soft dome as well?
"Something I said in my post that offended you? Do you really have to respond in such a rude manner to a normal question I asked? "
I have no idea why you would say that. What part of my post offended you?
Metal domes = ear fatigue
Natural fibre dome tweeters silk & textile (usually the same) = sonic bliss
Ribbon tweeters = only minor ear fatigue as well as make your dog a little crazy
Paper tweeters = 1965
Inverted domes = Focal
Diamond tweeters = in vogue in Beverly Hills and parts of Russia not PC due to their impact on the people of South Africa
Poly domes? = toss
Getting back to the OP, I think most people break it down to metal domes, fabric domes or ribbons. There are others exotic ones, such as plasma, but that's not really the issue, IMO. Many people seem to think that metal domes are harsh and silk domes are sweet - after all, it's silk, right? From what I have heard in many years of involvement in this hobby, is that a speaker designer can manipulate the output of a tweeter by padding it down or mounting it in a certain way. So it's more the designer's choices than the tweeter material that will determine the sound. Remember - bright speakers are initially impressive, leading to a quick sale. However, this becomes tiresome at home - hence the endless posts here about bright or harsh systems. The moral is - listen to the speaker as a whole and use your ears. The tweeter or woofer or cabinet material might be intellectually interesting, but ultimately, you have to like listening to the thing.
I don't think I have come across one metal dome tweeter that I really liked, no matter how well the designer manipulated it to try and give it a smooth sound. Some companies such as Vandersteen seem to do a pretty good job of implementing them though.
My father still has the original Advent Large speakers that he bought in the 1970's. They use a 3 inch paper driver. I think it sounds great. I don't think any modern day manufacture uses them anymore except Bose.
I keep wondering what is a Textile dome tweeter? What is it made of? How does it differ from cloth domes, poly domes, and synthetic silk domes?
My first speakers were a pair of the original Paradigm 7se's. They used a textile dome tweeter. I always thought textile domes were a little bit harder than soft domes but not metal?
I'm sorry if I seemed offended by your post. You said, "How come you didn't include camel hair tweeters in you list of soft dome materials?"
Camel hair? I guess I never heard of tweeters being made with camel hair before.
What manufacture uses Camel Hair in their tweeters?
I will be interested to know.
The main confusion with the soft dome tweeters is the misunderstanding of terms.
SOFT simply means what it says, soft, as opposed to hard.
TEXTILE simply means fabric. Ie. the industry that deals with the materials used in clothing is known as the Textile Industry.
So the terms Soft, Cloth, and Textile are all basically interchangeable.
It gets a little varied after that.
SILK is the specific material used in a Soft/Textile dome.
If the material isn't specified then it could mean anything but is most likely either cotton or some sort of nylon derivative.
Of course, no textile material is airtight without the addition of some sort of sealing material.
This is where POLYAMIDE comes into play. It's the glue that seals the textile in a soft dome.
All softdomes can technically be considered MATRIX materials. Matrix simply means that at least two different materials are mixed for mutual benefit. Fiberglass and Carbon Fiber are common examples of matrix materials. They mix a hard polymer with a flexible but strong cloth-like material. The polymer gives the cloth functional rigidity while the cloth material (the actual carbon or glass FIBERS) gives the matrix it's strength.
So, getting even more complicated, you can see that Carbon Fiber and Aramid (early Focal type) tweeters are sort of quasi soft/hard tweeters. They are matrix by design, just like Soft dome. But they are also rigid, like hard dome.
And they share pros/cons of both types.
Metal dome tweeters are typically made up wholly of whatever material they claim to be. Though not always. When the first Beryllium tweeters came out, only Focal had the technology to form pure Beryllium. So all others where hybrids. Though now others have caught up and there are others with pure Beryllium domes. Before Beryllium was Titanium. Titanium is also difficult to work with, though not nearly as Beryllium. It is also not toxic like Beryllium can be. And before Titanium there was Aluminum. Aluminum is by far the easiest metal to shape, but it comes at the cost of rigidity.
The whole idea with tweeters is to basically have the material be infinitely rigid while being zero mass. So you start playing with the various properties of the material. Titanium is heavier than Aluminum, but it is also many times stronger. So you can use much less of it, thus bringing the overall mass down for a given stiffness. Beryllium is even better.
BUT, as most people notice, all of this metal stuff comes at a cost. That being ringing. But that's a whole other subject.......
Thanks a lot! Your post was very interesting and informative. I learned much from it.
Well, I'll chime in, I've built with several tweeters and can speak from experience about some of their general characteristics... remember, no absolutes here, if you change the dampening material on any dome, the dome's sound changes. Let me preface this by also saying that I have never personally paid more than $100 or so for a dome, so my experience is limited to that, yet I have personally used dozens upon dozens of tweeters.
In general, the harder the material, the higher the material rings. You will see many metal domes that have a rise and some have a break up very high. In general, the harder materials have a more detailed sound, which is why you've heard that many hard materials can sound harsh. If a hard dome, whether diamond, ceramic or metal is properly damped, it should be very detailed and today, well damped hard domes are capable of some of the most detailed sound while remaining smooth with the right gear and front end. A great 3/4 inch metal dome is Hiquphon.
My least favorite domes have been mylar domes, cone breakup is very audible and these cones can't be pushed. Treated fabric has been mastered. I particulary like some of the better Seas and a Peerless HD (now scan speak), but many companies make a great fabric dome. While a fabric dome typically is not as detailed as a metal in the last degree, they are none the less, detailed, have an extended high end and offer low resonance so they can be crossed over with a variety of drivers.
Ribbons, are very fast & smooth sounding, but typically have a large variance in response curve and unless you use notch filters, most ribbons have peaks that I have found undesirable. Most ribbons also have a higher resonance hence they cannot be crossed very low. I have no experience with the mega buck ribbons and yes, they seem to have curves that affordable ribbons can't match.
Remember, these are very general statements and anyone with real experience could find a single driver to challenge a statement here. I hope this helps, Tim
Thanks for your post. My favorite soft domes have been from Dynaudio, Morel, and ScanSpeak. I find a lot of todays Seas soft dome tweeters to sound a bit on the bright side. I was not happy when Spendor switched from ScanSpeak to Seas for their tweeters. Especially in their Classic line. They always used ScanSpeak. I have a pair of Proacs that also uses the 3/4 inch ScanSpeak. Great tweeter. Wonder if they are still in business or did they get bought out by Peerless?
I'm glad you posted. My comment about the secret pricing structure, I hope, was taken just as some light hearted humour, and nothing more. Someone always seems to be complaining and/or joking about the high cost of some equipment, I just couldn't resist.
Unless I misread your post, it looked like you were trying to compare some of the more common materials to some of the more rare/exotic ones, with an emphasis on soft tweeters. API (Audio Products International), the parent company of several Canadian high end speaker manufacturers (Mirage, Energy, Paradigm, PSB and Athena are the ones I can remember. There may be others as well), make camel hair tweeters. They put them in Energy speakers and I think the original Mirage M series. I know several people that have these tweeters and swear by them. I'm not sure if they are currently going into any speakers but I'm pretty sure you can still buy the raw drivers.
Mezzanine, the Dyn and ScanSpeak tweeters are both very good, the few Morels that I have used had very good response curves and used at the right frequencies are excellent, not as detailed as they could be, but I have also found the Morels to have high HD that is very audible when crossed low.
What about magnésium. And the musicality..?
How about Accuton ceramic tweets?
Just a general observation: I've heard plenty of metal-dome tweeters that sound the way soft domes are reputed to sound, and I've heard plenty of soft-domed tweeters that sound the way metal domes are reputed to sound. I don't think you can make generalizations about the sound character of one or the other.
To my point of view à tweeter that does not have à contribution to the mid-driver can not realy help the speaker to breath.the only one the answered the need in the case of my speakers talon khorus II was AUDAS titanium
"Just a general observation: I've heard plenty of metal-dome tweeters that sound the way soft domes are reputed to sound, and I've heard plenty of soft-domed tweeters that sound the way metal domes are reputed to sound. I don't think you can make generalizations about the sound character of one or the other.
Very interesting post. I understand what you are saying but can you give some examples? For me, getting the high frequencies right, is one of my most important goals when setting up a system. Overall, I tend to prefer non metal tweeters. If you've found some exceptions to how metal tweeters typically sound, I'd really like to check them out myself. So far, I've never heard a metal tweeter that goes that far as to sound like a soft dome.
.. Then there is heil type folded diaphragm type still used in some speakers like goldenear. I've always thought these to have some unique advantages though I have also observed these as somewhat delicate and not hard to fry in years past. I heard a pair of goldenear aon speakers just today. Very smooth and easy on the ear with good detail. Had not heard a heil type tweet in years.
"Very interesting post. I understand what you are saying but can you give some examples?"
Offhand, I'd say that Harbeth and Totem both use metal tweeters that, to my ears, have none of the harsh, shrill metallic sound many people seem to associate with metal tweeters. As for soft domes, I've had some Spendor 3/1Ps and Vienna Haydns that, while not really exhibiting the shrillness people often associate with metal domes, had a certain hard, cold quality people don't usually associate with soft domes. (By the way, when I said I'd heard "plenty" of examples of both, I may have fallen victim to my own rhetorical devices; I should have just said that I've heard examples of both.)
A well designed tweeter of any material should never sound shrill or harsh. Again, whether you like the term "in general" or not, proper damping controls the rise and dips in any material and tweeter material in itself is not the deciding factor, but every material has a resonance and a ringing frequency, it is how well those peaks and dips are controlled and at what frequency that tell the whole story.
hi everyone I have an a/d/s L 880.the large dome midrange 206-0201. I have removed a piece of sticky-paper that fell on the top of the dome and by doing so some of the silky-smooth-finish on the top of the dome came off in few spots. I cannot hear any difference in the sound and there are no holes, you can just see that it is not as shiny and smooth as the rest of the dome, anyone's suggestions or I should leave it alone. thanks