Printable View
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.
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
Here's the driver that Robert has referenced ;
http://www.hostboard.com/forums/hbmc.../2009/06/7.jpg
- 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.
http://www.hostboard.com/forums/hbmc.../2009/06/8.jpg
Quote:
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...
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.Quote:
Originally Posted by Todd W. White
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
The ice pick to the forehead comment was interesting.
Titainum does successfully extend the UHF range of compression drivers eliminating the need for a tweeter in many applications, however. Altec alumium drivers typically do roll off considerably above 10K which has been debated often.
Quote:
Originally Posted by robertbartsch
I agree that titanium drivers measure more HF content...it's what's IN that content I am concerned with...
I think there are way more distortion components...apparently John Hilliard felt the same way...
A lot of people LIKE the harsh "JBL sound"...I am not one...I think old aluminum fram JBL's sound better...I own about 10 old alnico JBL's still...when I finally do kick off the redhead's gonna have an interesting yard sale...
JBL must have concerns too...they are coating the titanium, using beryllium, and making aluminum frams again...so it's obvious one size doesn't fit all.
As far as HF rolloff, many times it's done on purpose...it's not uncommon for playback systems to be 10 db down at 20khz, so for many apps it's simply not an issue.
The real bottom line is use whatever you want, I am just posting what I don't like...JBL worshipers have a tendency to take offense at the slightest criticism...without criticism products never get better...
Living with the redhead, I should have gotten a lot better....::rolleyes:
You're confusing material with size. Altec large format and small format diaphragms are made from exactly the same aluminum alloy, yet exhibit quite different performance bandwidths.Quote:
Originally Posted by robertbartsch
I find it interesting that with the exception of implantable hearing aids, where titanium has a signifigant biocompatibility edge, titanium has been of little use in microphone xdcrs. :)
Gold-sputtered polyester film is what they use on high end neuman condenser micsQuote:
Originally Posted by bfish
...which is just a minor tech advance over the metalized Mylar elements Altec developed in the '40s and continued to use for more than 30 years. :)
Aluminum is the best. Meyer is slowly converting to aluminum Talk Shop With John - The Development of Meyer Sound's High Drivers
Ev is still using titanium and so does JBL except for Their Line Array (Berylium).
Now if I wanted to go into the business again of FOH sound for small venues of 600 to 800 seats I would purchase 4 box of JBL line array for each side with Subs For each side.
Ymaha PM1D mixer one for FOH one for stage and one for broadcast.
Monitors in broadcast truck small JBL LSR and Altec Lansing 604 8HIII.
Stage monitors would be in ear
The 3 way snake splitter.
Fostex Digital 24 track recorders.
Outbord Equipment dbx compressors for low mids if I need to carry my sound further but would rather use delay towers instead and keep everything at an even 90 DB SPL.
Those Titanium phragms have got to go. I love the expression Ice Pick to the forehead.
Chow
With regard to manifolding -
Multiple drivers on the same horn require some sort of apparatus (manifold) to get them mounted up.
Early WE attempts were clumsy - I remember seeing some of them. Straight pipes screwed into threaded hole bored into a plate mounted to the throat of the horn.
Not very good - LOUD, but didn't sound good.
WE then changed over to the multiple-driver throats most here are probably familiar with, which worked pretty well.
Jensen and Magnavox, along with Harry F. Olson at RCA, all tried different approaches - some worked better than others.
The kicker is getting the waveforms to arrive in phase and combine, rather than subtract from the total SPL - in addition, out-of-phase signals sound pretty nasty.
EV tried manifolding several years ago - their "MT" series was heavily promoted and quite popular for a while. Their big problem was they forgot (if they ever knew) that you don't bend high frequencies around corners - especially at 90-degrees - and they had serious sound quality issues.
Jerry K. Hubbard, then Head of Acoustics at Altec Lansing, solved this problem - he divided the vertical diffraction slot on the MANTARAY horn throat into two parts: upper and lower. He then fed each half into the horn in a gentle, sloping manner. This eliminates the problem right angled manifolds had, and resulted in an overall increase of SPL of 4dB, instead of the theoretical 3 dB!
Sadly, this method only works with horns with straight vertical diffraction slots, like the MANTARAY, but it works REALLY WELL!
The modern approach is to use line arrays, which have all kinds of problems that have to be overcome, often using electronic trickery to accomplish it.
Barry McKinnon has an EXCELLENT article on line arrays. Read it here:
Loudspeaker Cluster Case Study
As far as my feelings on Titanium, I appear to be in good company...Meyer also says it produces distortion products.
" Titanium has good high frequency response because it is very stiff but it also has relatively high distortion and tends to fatigue quickly. Pure aluminum has a much longer life cycle but its high frequency response is not so good. Beryllium has a good blend of qualities in terms of efficiency, longevity and frequency response, but it is extremely toxic material to work with and so we ruled that out very quickly. "
I've been saying titanium makes a horrible surround for years, nice to see tests document what I hear. Most European titanium drivers copied Altec's Symbiotik idea.
Personally I find distortion a worse problem than bandwidth...a balanced system in terms of HF and LF...ie if you roll of the HF you have to do the same for LF or it will be bottom heavy...a system like that will sound better than one with a wider bandwidth and much higher distortion.
In the latter case the extra bandwidth actually makes the distortion easier to hear...
Old Guy:
The aluminum diaphragms sound more natural to me also. But, lets hope Readhead doesn't have the yard sale anytime soon, however!
If the aluminum units don't go as high, does anyone know if the "new" acquplased alumium JBL driver is coupled with a third driver - e.g a tweeter? These systems are priced in the statoshere so I haven't followed their specifics.
I always loved their 077/2405 slots and, in fact, I mated a pair to a VOTT system 30 years ago which was a good move IMO. I think they discontinued the slots when the Ti frams were developed; right?
IMHO best single item JBL ever madeQuote:
Originally Posted by robertbartsch
'zactly. Sytems that start to dump ~14-15kHz are only short ~1/2 octave of harmonics (and harmonic distortion). Take that same half octave from the bottom, and you're still at 30Hz, a challenge for most systems to play flat to.Quote:
Originally Posted by Old Guy
I'm wondering if perhaps my wife isn't one of those Titanium models. She can be a mite shrill to the ear and is virtually indestructible. Also like OG I should be top notch by now so that part of the equation isn't working apparently. :)Quote:
Originally Posted by Old Guy
Fish:
I'm not familiar with the large format Altec compression drivers but I assume they can go lower than the 1" Altec drivers.
Do they also roll off higher?
I have another Lansing system with a 2" Ti fram (2445) in my basement and that driver also rolls off considerably above 10K, if that is any comparision.
Actually 2445 is a 4" fram, 2 inch throat...
I think the small JBL's are 1 3/4" same as Altec, is that true?
Bear in mind, there are several different Altec bigger drivers...best is the 288 G/H they do better than the 2445 IMHO.
I have a several pairs of Ti frams in systems stacked around in and around the house.
Wow, I suppose every time I listen to them from this point forward, I will ask myself if I am getting the full ice pick to the forehead treatment.
Could be worse, Cerwin Vegas have a peak around Low Bottom E.:p
On another Lansing forum, the ice pick to the forehaed sydrome was explored and one respondent suggested that the person describing this treatment of Ti frams must have been listening to Kliphornz.
As far as I know, the Klips were manufactured by EV and never had Ti frams: right?
Quote:
Originally Posted by robertbartsch
Old Guy has a point there. While vacationing in Florida . Every night the hotel manager hired a new band and fired them at the end of the night. They all had JBL set ups. I minded my own business having worked with JBL pro systems in the 70's I noticed how bad these new drivers sounded and I could probably not fix their problem.I felt sorry for them cause with
the old 4530 cabinet and original drivers maybe I could have made it easier on every ones ears.
Quote:
Originally Posted by robertbartsch
Klipsch used Atlas mids and EV tweets mostly...there were actually Klipsch with western Electric guts way back...imagine what a set of those would be worth...
Note on the JBL forums they never criticize JBL it's always some other company...quoting blatantly prejudiced sources is not always the best way to get accurate info...
What ever you do don't go there and suggest Radian frams sound better in JBL's...they refuse to even consider it...even those who have never heard them...it's just impossible...
Maybe we should change "none so blind" to "None so deaf as they who will not listen"
JBL has done some wonderful things...and a lot are quite satisfied with those drivers...obviously JBL themselves are not, or why would they be making different drivers?
Religious followers are more dangerous usually than the founders of the religions...
That's not exactly how it went down;Quote:
Originally Posted by robertbartsch
[ame="http://audioheritage.org/vbulletin/showthread.php?t=25428"]...ever get an ice pick to the forehead? - Lansing Heritage Forums[/ame]
You started a thread there by quoting a member here out of context, who was subsequently called an ignorant idiot.
If you're gonna be a troll take it elsewhere. :(
I checked out that thread - sure am glad our folks don't behave like that here. Some of those images were disturbing.
Seriously.
Yeh, sometimes it is hard to get an un-biased opinion over there.
Sometimes?Quote:
Originally Posted by robertbartsch
Pardon me, but I think you are incorrect.
You NEVER get an unbiased opinion there...it's a JBL "club". JBL is almighty.
Todd please feel free to edit/delete any of my posts in this thread.
I started to do it myself then realized, this is honestly how I feel about what happened.
I do not like playing games and running from group to group spreading comments out of context....
The moderator cleaned up the thread at Lansing Heritage...and noted he does not entirely disagree with my opinion so the gist of the thread should stand.
I think WE are biased, too, but we can afford to be - we're RIGHT! ;)
Seriously, though, the members of this forum are like most Altec fans - even-tempered lovers of high-quality audio reproduction, willing to stand up for what they believe is right, and admit when they're not.
That said, I've noted the tendency the folks in the JBL side of the house (forums and other venues, as well) to be rather difficult when it comes to certain issues, even when presented with the facts.
A good example of this is what happened when Altec Lansing's Jerry Hubbard presented his AES Paper on the problems of HF driver distortion - even though he didn't name ANY manufacturer in the paper, the JBL people were quick to go on the defensive.
Jerry was right, by the way - the 4" diaphragm drivers DO generate harmonics that are so loud they become fundamentals unto themselves, then set up their OWN series of harmonics which then fight for dominance with the original fundamental and it's harmonics. The result is nasty...
Robert did post on the other forum that he is perfectly happy with his titanium frams...obviously he had a vested interest here....
Let's see...JBL engineers hear the titanium artifacts...that is why they use aquaplas and still make aluminum frams...I hear them...Robert doesn't...is he right, and JBL engineers, John Meyer, and I all wrong?
He put a lot of people thru a lot of grief to justify him not hearing what others hear.
That's exactly what trolls do. From Wiki:Quote:
Originally Posted by Old Guy
"Experienced participants in online forums know that the most effective way to discourage a troll is usually to ignore him or her, because responding tends to encourage trolls to continue disruptive posts ? hence the often-seen warning: 'Please do not feed the trolls'. "
A quick review of "find all thread started by" (on both forums)... will reveal the recurrent behavior. :Thumbs down:
not sure if any of you folks have read harvey fletchers book..'speech and hearing'...its pretty good, the research the folks at bell labs did in trying to accurately reproducing sounds, from syllables and consonants to all forms of musical instruements, from the gas flame to thermophones. i can only imagine the folks back then cringing hearing their s and t's through a titanium driver, its horrible