No, the Peerless, Accuton, SB Acoustics CDC, Eton Symphony, and TLabs aluminum oxide are all through and through, and not surface treatment oxidized only. They are all very fragile.
The TB 1719 was surface treated.
Looks like they're catching up to the best tweeters employing this. How many ultra lite, ultra rigid materials can there be?
Fiberglass honeycomb used for aerospace wing-fill is supposed to be lighter than paper and harder than steel. 4" cone (Mivoc) can reach 17khz, albeit very unevenly. Once I plast-nulled the 7khz breakup peak of my no-name 4" it was flat to >9khz and with a plast rossette waveguide beyond my hearing range.
To celebrate New Year post-Covid I opened a thread under fullrange, TLonken A5.2; directly and subjectively compared it against Joseph 2-way BR.
https://www.diyaudio.com/community/...r-5-2-in-evansound-3-75l.393909/#post-7219146
https://www.diyaudio.com/community/...r-5-2-in-evansound-3-75l.393909/#post-7219146
Retro tech story: as soon as I read the OP's first post, my mind immediately flashed back to the early 80s and my senior year in high school when I built two different sets of speakers in wood shop class. After finishing them (and graduating), I wanted to build another set & one of them was a two-way using a 10" woofer and a special driver I had been fascinated with since its debut at Radio Shack:
3-Inch Midrange Tweeter (it's listed on page 61: to get there, enter "61" into the left/black side of the page selector gizmo at the bottom of the viewer app; use mouse wheel to enlarge page*)
Seemed like a good idea to me: IMO a well-designed cone tweeter can sound decent, but usually only with smaller woofers i.e. 8" and below. So to me this was the "heavy duty" version of that, built so it could be crossed over at a relatively low frequency for use with 10" and larger woofers.
Unfortunately college got in the way of my building plans (no spare money and especially, no equipment to build the enclosure). So, another audio dream sacrificed to the attainment of my post-secondary education.
* when I first found that site about 10 years ago, I must have spent 2 hours there, swimming in audio nostalgia.....
3-Inch Midrange Tweeter (it's listed on page 61: to get there, enter "61" into the left/black side of the page selector gizmo at the bottom of the viewer app; use mouse wheel to enlarge page*)
Seemed like a good idea to me: IMO a well-designed cone tweeter can sound decent, but usually only with smaller woofers i.e. 8" and below. So to me this was the "heavy duty" version of that, built so it could be crossed over at a relatively low frequency for use with 10" and larger woofers.
Unfortunately college got in the way of my building plans (no spare money and especially, no equipment to build the enclosure). So, another audio dream sacrificed to the attainment of my post-secondary education.
* when I first found that site about 10 years ago, I must have spent 2 hours there, swimming in audio nostalgia.....
Probably a Foster FE83 variant loaded in a plastic cup.
I have some FE83A i am saving for something special. They came out of a Noresco WAW with a 10” AlNiCo woofers.
dave
I wonder if whoever took the pictures unfolded the leaflet, would there be a FR plot?
Many similar drivers are used in HT. Usually 80-86 db\m\w.
http://www.loudspeakerdatabase.com/ru/Beyma/3FR30Nd
http://www.loudspeakerdatabase.com/ru/Beyma/3FR30Nd
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Yep, I agree. The only caveat that comes to mind is how audible are "bending modes"? I've been wondering what happens with paper designs when the outer edges lag behind the middle of the cone -- if the speed of the transverse ripples is slower than the speed of sound, then the sound wave would sort of be progressively shaped as it expands outwards, and may form a sort-of bubble or virtual point source that pops out in front of the cone. Kind of like the way an exponential horn tends to slow down the edges of the sound wave.
Imagine at 20kHz, a soft cone might have 5 full cycles of ripples. After 5 cycles, the 1st cycle is already >85mm out in front of the cone, but if the air hasn't absorbed all the energy, the cone edges will still be generating the 1st cycle. So there could be a sort-of cardioid effect, where off-axis energy at 90 degrees is reduced due to cancellation. Maybe that's part of the secret to soft dome tweeters? Less diffraction.
OTOH, I think cone designs usually require stiffness to produce lower frequencies, so the internal speed of sound is increased, and smoother box shapes have to be deployed.
I hope my New Year's Weekend 3-way comp answered a few of your questions, in the realm of more traditional passive XO for home use.
https://www.diyaudio.com/community/...ir-5-2-in-evansound-3-75l.393909/post-7220838
Interesting info (and thanks for the clipped article). That surround seems quite substantial for a "midrange" crossed over at 700Hz, so it makes sense that is probably a repurposed full range driver.
I still think that's a handsome driver (function first of course, but good looks are nice to have). I've noticed many drivers back then featured exposed leads on the cone's upper surface, not sure why though.
No problem.
The real thanks go to whoever took all that time(!) scanning all those catalogs.Dome midranges: I also wanted to use that particular midrange for something (most probably the 3-way 8" dual-chamber reflex described in David Weems' book also sold at RS at the time), but was hesitant to do so because the dome's coating was incredibly sticky & thought dust accumulating on it was there to stay.