There is a pair of new Lansing compression driver components that are used in the new home settings (Model 435AL) on Fleabay now.
Apparently, they have aquaplased aluminum diaphragms!
I suppose you can guess from this that the other Lansing company believes these outperform titanium frams that have been their standard bill of fare on cinema, SR and other applications for about 20 years.
As far as I can tell, Altec and its successor GPA have always made diaphragms from aluminum; right?
Aluminum is softer...and easier to work...
When the lord said, let there be diaphragms, most were aluminum...JBL included...
RCA chose phenolic, and built some of the best phenolics IMHO...
Titanium started creeping in during the 70's..it wasn't till then that humans could form it cheaply. At least non-military humans.
I don't think there is a question that titanium is more durable...and in SR, EQ-ing the piss out of a system is preferred to having it quit.
Aluminum frams tend to be a bit more mellow...titanium is one reason for the "icepick to the forehead" JBL sound.
I don't like that sound, OTOH I have had heavy metal musicians complain my system didn't sound "irritating" enough..."it's too clean man!"
Since I have no intention of making that music my mainstay, no loss.
TAD uses beryllium, as do a few JBL's...however TAD vacuum deposits beryllium and JBL stamps it, cheaper but creates stresses. Frankly Radian aluminum frams in the TADs sound pretty darn good at 20 percent of the cost...
IOW titanium is brighter and harsher. Sorry so verbose.
Note to JBL guys..I own some JBL stuff and love it, just not titanium frammed stuff.
Your neighbors called. They like your music.
Originally Posted by Old Guy
- TADs' 4001 diaphragms had a regrettable habit of dome shattering when used for SR duty .
- Their failure rate all but doomed their widespread acceptance within the industry ( becoming instead a high priced albatross for the owners ) .
- Every company that thought they were buying a "leg up" over the competition by getting 4001s, found out a very expensive lesson .
- Companies that buy JBLs' beryllium products aren't suffering the same financial penalty / granted, most aren't buying JBL Vertecs for the glamour of beryllium .
>< cheers
ps #1; there's some good anecdotal coverage on the type of Be that JBL "outsources" for their Be dome in Steve Lowrys' article about "Beryllium Fraud" .
ps #2; the company that manufactures the Be domes for JBL can be read about here .
The beryllium diaphragms are dangerous - you must be VERY careful not to come in contact with them with your bare skin. I remember TAD sending protective gear with their diaphragm kits and warning notices in the instructions.
You mus also NOT breathe vapors off of them if they've been exposed to anything that has made them corrode. It can poison you.
As for titanium, Jerry Hubbard did a LOT of testing of different diaphragm materials when he was developing the Pascalite (299) diaphragm. I asked him about it at the time, and he told me that it exhibited some "interesting distortion characteristics" that rendered them unacceptable, therefore, for use in an Altec HF driver.
Manifolding, if done right, is a great way to go when you need high SPL's, but want the duraluminum sound...
Todd W. White, Owner & Webmaster
Altec Lansing's (unofficial) Homepage
While I don't beleive I'll run into any beryllium diaphragms any time soon........thank you for letting us know. I don't think that's anything I'd want in my house.
Audio_by_Goodwill
Michigan, USA
todd..can you explain 'manifolding' ?
old guy..the ice pick to the forehead is such an accurate discription, too true
and for what its worth..bills phrams sound so smooth, tho i do want to try phenolics in the large formats,as im running 4 way now, crossing out of them earlier would be no problem. the clarity w/o the harshness can be truely appreciated in high db situations when all other systems ive ever heard are straining to keep clear. just big and loud doesnt work in the rta. i havent experiernced listene fatigue for years, well not at my house anyway. which is something titanium phrams does for me usually on the first few notes
"those sounds to which no definite pitch can be assigned are usually classified as noise"<br />harvey fletcher-1928
AFAIK except for the phenolic units used in the 730-731 PA drivers, though these may have been outsourced.
I wasn't aware of this particular array series, but it's about time they did something with those shrill, ear piercing Ti units. I airbrushed them with Dammar. Ditto on work hardened aluminum units. I'll take 'smooth' over 'extended' any day.
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
Here's the driver that Robert has referenced ;
- JBL has been offering an aquaplased (plastic-coated) titanium diaphragm for around 15 years now ( "airbrushed" on, btw GM ) .
- This plastic coating greatly mitigates the "bite" / "zing" / "ear-wire" tendency of the titanium diaphragm .
- To my ear, the coated "Ti" type is still brighter than any stock aluminum diaphragm that I've heard .
- FWIW, Tannoy was the first to publish ( that I've seen ) printed copy, referencing the plastic coating of a HF diaphragm ( in the Silver Series from the late 50s ).
- HiFiLit is the reference for that bit of trivia .
>< cheers
ps ; Here is HiFiLits' reference to the plastic-coated aluminum alloy diaphragm.
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