Advantages of beryllium?

I run TADs and BE does have advantages its lighter stiffer has high resonate frequency before material breakup. But its highly toxic sure as a user you most likely will not BE exposing yourself family or pets to BE poisoning but maybe the place were its mined did or maybe the miner maybe the factory worker maybe anyone handling it in the future. So to me if you want BE buy vintage dont support modern production of BE drivers in things as disposable as a modern loudspeaker.

In terms of the diaphragm, both Al and Ti have very similar stiffness with a given density. So when shaped, the weight will be quite similar between the to when targeting a specific stiffness performance, but the titanium part will thin in comparison due to its much greater density. Titanium will be somewhat more forgiving if over driven or out of bandwidth as it has greater internal dampening as compared aluminum alloys. So while Ti is a touch better than Al in overall performance, there is an added cost to its source and manufacture.

Be on the other hand can perform at much higher levels than either Al or Ti. A higher modulus than Ti and lower density than Al. This causes it to be highly damping, but not internally. Being very rigid, a Be diaphragm maintains is shape under a significantly high stress, but internal dampening is more about specific elasticity and this is where Be and Al share a commonality as neither have much elastic capability. Ti actually has quite a bit more elasticity, especially for a metal. So with Be or Al, its important to not go beyond the designed capability. Its important to do so with any driver, but the resulting output distortion will be higher. The designed capability will be very driver specific as the shape, size, thickness, quality of process will dramatically affect these figures. FEA applications will be primary point in the design process for modern drivers.

When Be is being formed, the dust that can be inhaled that can be hazardous. When formed in shape, its pretty stable and even when broken isn't quite as hazardous as it would be in a manufacture facility with volumes and processes being applied. It still needs to be handled appropriately in those situations.  

Paradigm's new Persona line use's Truextent Beryllium mid/bass driver's and tweeter's in the entire line. 

Don't be fooled just by the Be brand. They are not all equivalent, certainly not in frequency response or dynamic range.

In _theory_, be is very stiff and very light, so least stored energy or resonances of most materials.

The implementation of the suspension, motor, and overall speaker design is VERY important. Done well the best Be tweeters are among the best tweeters. But so are the best AMT's and ring radiators too!

Best,

E

One good eye opener, listen to the Magico Be tweeters and compare to the Focal's.

Personally I find the tuning of the Magico's a bit bright, but butter smooth and wide dispersion spanks all the Focal's and certainly the B&W diamond tweets.

It's all in that luscious motor assembly that's behind it.

Best,

E

Highly rigid and light but poor internal damping.

Personally I don’t like the splashy sound of drivers of this type design (metal and highly rigid). They have great bandwidth that makes for impressive measured performance but I find the sound is "splashy" due to the way rigid materials vibrate naturally (like a bell vibrates and rings after an initial hit but a damped material like a pillow does not).

Splashy is a good term - as in when you splash the water it makes a lot of sound after the initial splash. Acoustically this means the driver imparts its own sound to the timbre whereas an internally damped cone material is much more inert - contributing much less coloration after the sound stops.

I prefer damped designs even though they tend to have a narrower bandwidth and can suffer from breakup and therefore require more careful design and larger more expensive drive motors. Damped cones sound much more natural and faithful to the original tone/timbre of recorded instruments even if they are not as linear on a speaker frequency plot.

Here is an example of a titanium tweeter - look at the ringing in the waterfall plot in the treble !!!

https://www.stereophile.com/content/jmlab-utopia-loudspeaker-measurements-part-2

Here is an example of Be - similar problem in the treble but very much better than titanium

https://www.stereophile.com/content/focal-maestro-utopia-iii-loudspeaker-measurements

beryllium is 1/3 lighter than aluminum yet 6x the specific stiffness of steel

IIRC, it outclasses Ti in that way - dunno re stress cracking but the newest Ti alloys are better than their reputation

the dust is highly toxic - ask Porsche who used them - briefly - on brake components of some race cars

might be fun to see if the German govt. allows Be in speakers - you can get away with putting toxic liquids in cables in Canada and importing them into the US though

If a Be tweeter is properly constructed, there won't be any ringing in the audible band and well above it. While it has very low internal damping, implemented properly it is considered what would be called high damping, so rigid that it really doesn't resonate.

Now as for those delayed energy charts, look through all the measurements and read the comments. In the older Utopia, the mid driver wasn't well isolated and was impacting the tweeter and it does reach its breakup point is at 22khz and certainly does show. So there is a number of issues that design resulting in that measurement. Focal also didn't develop a great driver in this case as we have seen many other metal drivers of lesser material measure extremely well in the decay plots. Even Al, which should be one of the worst materials but has resulted in some of the better measurements is mainly due to the quality of implementation. The material certainly has an impact, but its use in design matters more. 

https://www.stereophile.com/content/kef-r700-loudspeaker-measurements

The Kef R700 uses a plebeian Al dome, but due to a designed shape and stiffening ring, measures perfectly clean. Kef uses just an alloyed version in the Reference and Blade series and gets the breakup point beyond 30khz. Associating a sound with material is for the most part is invalid and proper design and engineering is the correct answer. You can just as easily implement a fabric dome poorly and have messy decay plot due to energy coming elsewhere.

Those Focal speakers didn't achieve their designed goals and they likely knew it. Reached the end of the cycle and budget and released the product as it was, being the best they knew how to produce at the given time and a given cost. Looking at the Sopra 3, they still haven't quite gone as far as some other companies in spectral decay, but progress has been certainly made. 

@mmeysarosh

The KEF R700 does measure well but the tweeter still has some hash and is not nearly as clean as the Seas Excel Millenium tweeter - see the outstanding lack of resonances (much better than any metal dome) in the waterfall plot for this speaker with the Seas Sonotex dome in their Excel Millenium tweeter (around 200 euros each!)

https://www.stereophile.com/content/joseph-audio-rm33si-signature-loudspeaker-measurements-part-2

@koost_amojan

You need to look for a clean waterfall with fast (damped) decay and no hashy stuff or resonances. The main resonant ringing is not normally in the audible band - my concerns are the additional resonances and lack of damping in rigid domes. The titanium dome on the JM Lab Utopia is up to 2 msec across the treble - this is a lot of vibration compared to something mostly clean or down 20 dB after 0.5 msec.

Here is a waterfall plot just for the Seas Excel Millenium fabric dome tweeter.

http://www.diyspeakers.net/snippets.org/ldsg.snippets.org/graphics/seas/e006w.gif

@kosst_amojan

Obviously some implementations are better than other. My statement pertains to the problem of lack of internal damping in most metallic drivers (magnesium being perhaps a notable exception).

I count 5 resonances on the Focal Aria tweeter lasting up to 1.5 msec. These resonances are much much longer than the wavelength of the sounds that tweeter emits (an eternity in terms of PRAT) and will definitely color the sound in the way I described.

The resonances are multiple as a rigid disc has multiple resonant modes. I know this for sure as I have large collection of Sabian, Zildjian and Paiste cymbals and they shimmer with all kinds of non harmonic tones. A cymbal is an exaggerated example but the same principle stands.

If you want to hear musical timbre you need a driver that is critically damped - being inert it just gets out of the way once the desired movement is executed.

2 msec of waterfall hash on the first example I gave is really going to affect everything: the timbre of transients on percussive instruments (twang of guitar strings) to the articulation of sbilance on vocals.

The high but very narrow or sharp resonance peaks sometimes seen on JA plots is something to do with his measurement setup - you can ignore those - they look too narrow to be real effects.

FWIW the best waterfall plot I have seen, apart from the one on the Joseph Audio speaker linked above, is on a Quad electrostatic. So for those people who can hear what a difference a good electrostic speaker makes audibly in timbre then you can appreciate how a rigid tweeter can be coloring the sound in the way I describe.

@randy-11

Interesting link. I think they sum it up very well. Be is better in the very top octave than Aluminium or Titanium (10 to 20 KHz)

Note that on the plots Be is not necessarily the best from 3 to 10KHz (the really important range musically for the tweeter). This is the point I am trying to make about internally damped drivers - better performance over a narrower frequency range. If the sound from 10KHz to 20KHz is most important to you then Be is the way to go (at the expense of more resonance at 3KHz to 10KHz)

As as far as I am concerned there is not so much musically in the 10K to 20KHz range - so I prefer a tweeter that performs better from 3KHz to 10 KHz.

A - The 936 is not very clean
B - It has the Focal 100 Hz dip in impedance, which makes the speakers seem more "discerning" of various amplifiers. In some cases this is done artificially in the crossover.

Best,

E

shadorne, I dunno if what they say is accurate but it does seem to be a  pretty good summary - I'm not a dome kinda guy (Maggies) - tho if someone offered me a free pair of Sonus Faber Aida's I could be persuaded to switch.

@erik_squires 

Does the 936 have a Beryllium driver? Or is that reserved for higher up Focals?

Per the web site, it is Al/Mg.

Nothing against Al/Mg but Focal has this fetish for micro motors which are never as smooth or dynamic as the large motor variants.

Though lately ScanSpeak has produced some tweets which are close to the same motor size and very very good sounding.

@erik_squires 

What do you mean by micro motors? I don't understand that term, sorry.

I worry that people will accidentally stick their fingers into the tweeters of those precious Magicos…and according to at least one guy who sells them it seems that's not such rare a thing. My fragile aluminum-magnesium tweeters are covered by a mesh screen so have another drink cousin Shirley! Just don't knock the damn speakers over.

Micro-motor tweeters are just tweeters with the bare minimum motors to work. Focal as well as B&W are proponents of this approach. The motor is no wider than the dome and usually less than half an inch thick.

Despite assertions otherwise, popular micro-motors measure terribly across distortion, frequency and lack of linearity, regardless of material used.

They are routinely outclassed by relatively inexpensive models from popular driver vendors.

Best,

E

Does seem one poster has no idea what a TAD driver is  http://www.technicalaudiodevices.com/pro-hf-units/  and he seems to suggest vintage doesn't perform as well as modern I suggest he point me towards a BE equipped modern driver with better specs than a TAD? 

kosst :

Sounds way too much like work. Buy whatever you’d like to listen to, but I’ve never seen specs or heard a micro-motor tweet perform as well as mid-grade tweets from SB, ScanSpeak, Seas or even Peerless.

There is a popular ring radiator from ScanSpeak ScanSpeak Discovery R2604/8320 (and a relatively lesser Peerless variant) that has been used by Magico, YG, Krell and Sonus Faber. I put that tweeter against any micro motor tweeter I’ve ever heard.

Also, the ScanSpeak Be that is the basis for the current Magico Be/Graphene tweeter is also far better sounding and measuring.

Best,


E

https://www.madisoundspeakerstore.com/air-motion-transformers-amt/mundorf-amt25d6.1-r-dipole-air-mot...    https://www.madisoundspeakerstore.com/soft-dome-tweeters-morel/morel-titanium-supreme-tsct1104-tweet...  https://www.madisoundspeakerstore.com/ribbon-tweeters/raal-original-140-15d-ribbon-tweeter-with-amor...          in my own hands on experience these options sound better than BE options from SEAS ScanSpeak and Satori   

Hi @johnk

My main speakers use the Mundorf AMT's.

I wouldn't call them the best... but I would call them among the very best. :)

Implementation and room matter a great deal too, but I absolutely agree they are among a small, stratified set of tweeters that should sit at the top of the hierarchy.

Best,

Erik

I heard TAD Be drivers in the mid 1980's. No way I could sit and listen to one then.

Maybe it was the electronics (Haffler) but ouch!

Best,

E

Wow, that Alexx waterfall plot is a disaster. It’s too bad you didn’t link to the actual measurements page where in the last (useless) paragraph where JA (if he needs to completely ignores the measurements and) blows sunshine up the manufacturer’s butt, even he has to grudgingly note how bad the waterfall plot is.

In a publishing universe of almost completely subjective waffle without facts I like JA's measurements and graphs. I have learned to read his prose very carefully, and ignore the commercial talk. The amplifier measurements with a simulated real load are particularly revealing, I find.
Fortunately there are a few other international publications with fact based reviews.

@Koost_amojan

You are correct. The cost of the speaker is no reflection on the quality - especially the tweeter.

The Excel Millenium Sonotex soft done tweeter has the best waterfall I have seen. It is expensive at around 200 euros per unit and therefore very few manufacturers use it.

Since most speakers are fairly good in frequency response the waterfall plot plot is far and above the most important speaker measurement. Another key plot is the dispersion horizontally.

Unfortunately not many folks understand the importance.

@bar81

+1 Exactly how I read JA last paragraph. Full of euphemistic BS whenever the POS SOTA ultra expensive audio jewellry measured performance is poor in certain aspects. He is also careful not to compare products and be overly enthusiastic when performance in a reasonable price product is exceptional - usually just saying he is impressed. After all a reviewing magazine needs advertising revenue and cooperation from the industry - so it can't pick winners and it's job is to cheer on every latest product. So kudos that JA still manages to convey his views to those who are discerning enough to translate that last paragraph.

I'm sorry, did we want to talk about the price of speakers, or their sound quality? I'm confused.

As I've written, JA loves speakers that sound like hearing aids. If that's what you like, feel free.

https://speakermakersjourney.blogspot.com/2016/05/stereophile-reviews-data-doesnt-lie.html

Best,

E

@erik_squires

LOL The author is entirely correct about smiley EQ curve speakers with the standard industry midrange scoop ....however this is INDUSTRY WIDE - you can hardly blame Stereophile or JA for what consumers want and buy in huge quantities. Junk food is bad for you too but people love it and but it in large quantity! This has been called mid scoop or BBC dip but it is highly prevalent - B&W dominate this style sound.

If you don’t like industry standard smiley EQ (presumably because you don’t yet need hearing aids) then get ATC which are flat (but actually sound midrange forward compared to most everything else.)

The market largely consists of elderly white men with degenerated hearing who claim to have golden ears. It is ironic indeed, but the result of this combination is that the market is now gutted with overly bright speakers that are tiring to listen to.

I don't actually have a problem with smile shaped FR curves, as they are ideal for low-volume listening. I also don't have a problem with buyers who like a particular flavor of speaker.

Notice what JA likes is more than a smile, but a hype curve. The selective exaggeration of a couple of bands in the treble, and suppression of others, and then JA has the nerve to call neutral speakers "colored."

Of course, buy what you like. Enjoy what you like, but the "High End" sound as promoted by JA is a very particular set of colors.

Best,

E

@willemj 

This is a side note: extrapolating from your post one would think that audiophilia will die with baby boomers. It is an interesting hypothesis and I feel that it contains more than just a nugget of truth.

@willemj

yeeeap.

And there is nothing wrong with buying speakers that make you feel younger! :) but call it what it is.

Best,

E

It is indeed a dying market.

I’m a millennial hipster idiot. I bought Harbeth P3ESR and some Rega stuff if that counts as a start of saving it...