...ever get an ice pick to the forehead?

[robertbartsch]

In a recent conversation of knowledgable folk on another forum, one person described the sound from compression drivers with titanium diaphragms as the classic ice pick to the forehead sound.

I never really found them to be harsh or outwardly forward but I suppose I enjoy horns in general but I beleive many do not.

...anyway, I suppose this is an amusing description by one who does not.

[oldsoundz]

This person may have been listening to Klipsch.

Every Klipsch speaker I have heard and owned has sounded shrill to me.

On the other hand, I have loved every JBL horn that I have heard so far.

Maybe its just me

[BMWCCA]

I'm reading this thread while I listen to the 4345s with their 2306 horns and 2425J compression drivers with factory JBL titanium diaphragms. Couldn't be happier, and I'm not reaching for the ice-pick. :dont-know

[Titanium Dome]

As much as it pains me, there are some bad Ti drivers out there, but like Jessica Rabbit, they're not bad, they're just drawn that way.

[robertbartsch]

Man, I thought the Klips were manufactured by EV and never carried Ti frams...

I think the guy who made the ice pick to the ferehead comment was a former employee of a Lansing company so maybe he or she has become a tad bit forgetful...

[jbl_daddy]

Next time you see him just tell him he is an idiot.:)

[Mr. Widget]

...anyway, I suppose this is an amusing description by one who does not.Exactly!

...and we should always remember they out number us... which is a good thing, if everyone enjoyed the ice pick to the forehead sound we'd be paying far more for our speakers.;)


Widget

[robertbartsch]

..these things are way too dangerous!

.....dispite what the Second Amendment says, I think we should outlaw ice picks!

[JBL 4645]

In a recent conversation of knowledgable folk on another forum, one person described the sound from compression drivers with titanium diaphragms as the classic ice pick to the forehead sound.

I never really found them to be harsh or outwardly forward but I suppose I enjoy horns in general but I beleive many do not.

...anyway, I suppose this is an amusing description by one who does not.

He wouldn’t be watching Basic Instinct by any chance?:D

http://msnbcmedia.msn.com/j/msnbc/Components/Photos/060329/060329_basicinstinct_vmed_12p.widec.jpg

I find some music or film mixes to be very toppy bright with harsh edge. I just tone the level down on the front HF LCR.



In the case of Johnny Boz who got buggered up pretty badly by titanium HF Ice Pick!:eek:


Exactly!

...and we should always remember they out number us... which is a good thing, if everyone enjoyed the ice pick to the forehead sound we'd be paying far more for our speakers.;)


Widget


I'm reading this thread while I listen to the 4345s with their 2306 horns and 2425J compression drivers with factory JBL titanium diaphragms. Couldn't be happier, and I'm not reaching for the ice-pick. :dont-know

I hear there real cheap at Kmart!:D

[Tom Brennan]

Funny, upon auditioning speakers recently my wife and I listened to Maggies and they have a definate shrill resonance in the treble, more subtle than the spikes in a Klipsch Heresy but most certainly there. After a few minutes they were setting my teeth on edge and giving my wife an earache.

Yet unlike horns Maggies are "audiophile approved" and people are free to interpret the resonance as increased detail.

[LowPhreak]

To be fair - I've owned some Maggies, Tom (2.6R and Tympani IV-D) and I didn't hear what you describe. That's not to say the model(s) you heard weren't that way.

robertbartsch -

I do find the 2426H/2370A combo needs some cut in the 2-4kHz area, but nothing that isn't manageable.

[old guy]

I made the comment about titanium frams. I do NOT LIKE THEM. Neither does John Meyer, and a host of others. Note JBL engineers are also playing with Beryllium and are bringing out new aluminum frams. If titanium is the be all and end all, why are they doing that? There are measured artifacts induced by titanium..they ain't perfect.

I own JBL's. Mine have the old aluminum frams. I prefer that sound.

[old guy]

I've been a member here for years..I know Don from several Usenet groups.

I an a retired Pro sound engineer...I have spent most of the last couple years doing chemotherapy...

When I tried to post the other day my account for some reason no longer existed.

I look forward to sharing and learning.

[mech986]

Well, we have to remember what the Ti diaphragms were supposed to do. When JBL researched and then introduced them, they were created in response to the problems with the Aluminum and dural diaphragms in use then - namely, limited lifespan, especially with the advent of higher power and SPL requirements, relatively older voice coil technology including adhesives and power handling, and the need to create a tougher and more durable diaphragm that could meet the prevailing sound requirments.

My understanding is when JBL got into the portable sound and higher SPL touring and Cinema markets, they started to see all kinds of failures that indicated the aluminum parts, while sounding great, had reached the limits of their design. Trying to find a compatible yet tougher material while holding down the cost efficiently led them to Ti.

They introduced the smooth Ti diaphagms and further development and research indicated the metal dome resonances were a problem. The diamond surrounds and then the ribbed pattern domes were an effort to tame and harness those resonances to extend the frequency response while maintaining the desirable characteristics of Ti. All of this was done over 2 decades while thousands of speakers were in operation daily in venues all over the world. JBL was responding to their needs as well as looking out for their product warranty issues.

I think JBL would acknowledge that the Ti diaphragm, like all products, has its plusses and minuses. With renewed effort from Harmon and push from the engineers, the newer Aluminum and now Be diaphrams are further signs that JBL continues its research and push for the best products out there. Yes, they do cost a fair amount but what newer and better technology doesn't have its development costs that must be recovered.

Some would say that the Ti phragm can also be tamed somewhat with judicious EQ at the top end. Others don't care for them - that's ok. If one understands what they are for, each can pick the pieces that they like.

I'm glad that JBL can provide so many different choices for so many markets. I've always wondered what a Vertec Array might sound like in my living room!!

My 0.02, your mileage may vary.

Regards,

Bart

[old guy]

Well, we have to remember what the Ti diaphragms were supposed to do. When JBL researched and then introduced them, they were created in response to the problems with the Aluminum and dural diaphragms in use then - namely, limited lifespan, especially with the advent of higher power and SPL requirements, relatively older voice coil technology including adhesives and power handling, and the need to create a tougher and more durable diaphragm that could meet the prevailing sound requirments.



Bart

Spot on...best sounding system in the world is useless if it doesn't survive the gig...

But I still use aluminum at home...again just my preference...

I think forming titanium cheaply didn't come about till the 70's or it would have been used before...I suspect engineers were checking it out way earlier...

Some amazing things have never made it out of the back rooms...sadly many experiments were just destroyed or dismantled...companies didn't want competitors to see them...

[4313B]

In a recent conversation of knowledgable folk on another forum, one person described the sound from compression drivers with titanium diaphragms as the classic ice pick to the forehead sound.

I never really found them to be harsh or outwardly forward but I suppose I enjoy horns in general but I beleive many do not.

...anyway, I suppose this is an amusing description by one who does not.I guess I really don't understand the point of this thread. We've been over the various diaphragms and why they exist in lurid detail.

What I've learned is that everyone thinks the aluminum diaphragms sound better until they have to put out $568 for a pair of new ones. Then they suddenly think titanium at $276 a pair sound just as good.

I won't even bring up the magnesiums or berylliums because they aren't sold at Walmart.

The aquaplased titanium diaphragms are perfectly fine for 99.99999% of consumers, especially after you tell them the price of moving up. :applaud: :rotfl: That's just the way it is.

And JBL's number one selling large format Studio Monitors of all time ran titanium diaphragms without aquaplas... which means that anyone who thinks they suck should probably look at the rest of the JUNK in their audio chain first...

[Tom Brennan]

Titanium sounds good to me, I used to use 2426s on Edgar saladbowls and Altec 1005s and recently used CS-3115s which use 2426s (and coexisted in the same house with two sets of Altecs with aluminum diaphragms).

[badman]

A lot of it, also, is attempting to use contouring to get top octave response out of the Ti diaphragms. The 2426 is well-damped (moreso than most Ti compression drivers, anyway), but the breakup is in the top octave, so when a design tries to squeeze that last bit of extension, they're doing so by operating it in breakup mode. I'm working on some Oblate Spheroid waveguides for them, but will use a small supertweeter to get the content above 10k, and simply accept the lobing, perhaps even rear facing as an 'ambience' tweeter.

[mech986]

Spot on...best sounding system in the world is useless if it doesn't survive the gig...

But I still use aluminum at home...again just my preference...

I think forming titanium cheaply didn't come about till the 70's or it would have been used before...I suspect engineers were checking it out way earlier...

Some amazing things have never made it out of the back rooms...sadly many experiments were just destroyed or dismantled...companies didn't want competitors to see them...

BTW Old Guy (with that name you'll fit right in here!),

Welcome to Lansing Heritage! Hope you'll share what JBL's you have and how you're using them. As you can see, we're all passionate like you are about JBL's products and legacy. Hiope you enjoy the discussions.

Bart

[mech986]

Forgot to add that most of the Ti being used in the 70's was for aerospace and military applications. As forming technology and experience became more widespread and known, Ti became somewhat more of an option. Couple that with the winding down of the Vietnam War and downturn in the aerospace industry, Ti prices came down and Ti experienced suppliers and companies needed to diversify their business. Granted, the amount of Ti JBL uses in a year probably would supply a few Boeing 777 wing spars.

I even remember a Titanium based Can-Am sports car call the AutoCoast Ti-22 (periodic number) that raced in 1970-72. Of course, most all racers used titanium extensively till they could afford to go to carbon fiber.

Hmmm, carbon fiber compression domes. Have seen that in woofer cones but I suspect too brittle for domes and probably too heavy in the thicknessess needed.

[old guy]

Hmmm, carbon fiber compression domes. Have seen that in woofer cones but I suspect too brittle for domes and probably too heavy in the thicknessess needed.

Interesting idea...it would have to be super thin to be light enough, wonder what breakup mode would be like?

Perhaps some sort of "sandwich" a thin carbon fiber fram coated with an ultra thin layer of metal..a lot of things can be done with vapor deposition...I would bet somebody has already tried it or is trying it...

[old guy]

sounds good to me

The ideal end point to any discussion:applaud:

The user is always the final authority on where his money goes...except in my case...I have the government and a girlfriend...

[mech986]

Interesting idea...it would have to be super thin to be light enough, wonder what breakup mode would be like?

Perhaps some sort of "sandwich" a thin carbon fiber fram coated with an ultra thin layer of metal..a lot of things can be done with vapor deposition...I would bet somebody has already tried it or is trying it...

JBL tried that with the 066 tweeter - aluminum vapor deposition over linen/phenolic dome for the L166/L212/4411. That was over 20 years ago! I suspect the process could be much improved if it was deemed useful enough to re-engineer (and cost effective).

See write-up here:

http://www.lansingheritage.org/images/jbl/specs/home-speakers/1976-l166/page2.jpg

[brutal]

It's hopeless for me to grasp this thread because as soon as I saw "icepick to the forehead," I thought Frank Zappa and can't get it outta my head.

LOL

[toddalin]

A lot of it, also, is attempting to use contouring to get top octave response out of the Ti diaphragms. The 2426 is well-damped (moreso than most Ti compression drivers, anyway), but the breakup is in the top octave, so when a design tries to squeeze that last bit of extension, they're doing so by operating it in breakup mode. I'm working on some Oblate Spheroid waveguides for them, but will use a small supertweeter to get the content above 10k, and simply accept the lobing, perhaps even rear facing as an 'ambience' tweeter.


And this is what I think I hear in the 4430s that I don't get out of the L200/300s. (Or maybe it's that ferrite magnet as opposed to the AlNiCo, and/or a combination.) I imagine this becomes moot when the 2425 is used in a 3-way system.

[4313B]

Improvements in Monitor Loudspeaker Systems (http://audioheritage.org/vbulletin/showthread.php?t=7852)

JBL Technical Notes Volume 1 Number 8 (http://audioheritage.org/vbulletin/showthread.php?t=4410)

4430/35 (http://audioheritage.org/html/profiles/jbl/4430-35.htm)

[old guy]

JBL tried that with the 066 tweeter - aluminum vapor deposition over linen/phenolic dome for the L166/L212/4411. That was over 20 years ago! I suspect the process could be much improved if it was deemed useful enough to re-engineer (and cost effective).



Much of the advanced technology of today is just materials making it possible to implement ideas from a long time ago...I can't help but think how much was lost though...

I LIKE to see crazy ideas, whether they worked or not...the stealth bomber is a case in point...much of the technology was laid down in the 1940's at Northrop with the flying wings....and still never declassified...but the aircraft were unflyable with mechanical controls...

It took computers to make them airworthy...

[Robh3606]

...ever get an ice pick to the forehead?


Only when I listen to "Fembot in a wet T shirt":D


Titanium sounds OK to me. Even the uncoated versions in the Ti series, L series, 4200's, 4400's, XPL ect.

Rob:)

[LowPhreak]

Only when I listen to "Fembot in a wet T shirt":D

:applaud:


http://upload.wikimedia.org/wikipedia/en/9/9a/Zappa_Joe%27s_Garage.jpg




Titanium sounds OK to me. Even the uncoated versions in the Ti series, L series, 4200's, 4400's, XPL ect.

Rob:)

:yes:

[boputnam]

I an a retired Pro sound engineer... I look forward to sharing and learning.Tell us more about that career? It's nice to have someone with that experience here - many questions come up.

And, sorry about your illness. That is no fun. :no: For over a decade in my youth, my mom drove patients to get treatment(s) - we saw it all. It is hard work, that...

[old guy]

Tell us more about that career? It's nice to have someone with that experience here - many questions come up.


Not a whole lot to tell....:blah:

I started out about 15 working with friends in a garage band..I was one of the local science geeks...back then a state-of the-art garage band PA was a 100 watt Bogen amp and a pair of EV 848 horns on stands...lots of bands were willing to play before us 'cause they didn't have a PA. This is before Shure Vocalmasters really became popular..

Doesn't take long for a person with working ears to realize the limitations of that setup...first thing I did was bass reflex boxes underneath and crossovers to the horns...sounded a heckuva lot better but still sucked...

By the late 60's had real gear, mostly homemade...no such thing as a cheap mixer then, you wanted one you built it..

Got picked up by a local sound company, did a number of "B" level acts...Kenny Rogers with the First Edition...before he became a country star...

I did a lot of 50's and 60's acts...in the 70's...Sam and Dave, Junior Walker and the All Stars, Carl Perkins, acts like that on their way thru here...

Most interesting show I ever did? Google a band called "Trapeze". The were passing thru town...got like 50 paid admissions...felt so bad my hyperactivity kicked in...I worked with people who did charity shows at the Agora in Columbus...made a deal for them to play the charity concert the next night...they were broke and staying at the Agora's band house...the band played the charity concert for free but I talked the charity folks into spotting them a hundred...the concerts were an ongoing thing, usually 4 local bands, and drew crowds of 1000 or so...this was before the 70's gas crisis, a c-note still bought a lot of gasoline...



Very briefly worked for Altec in the early 70's...it just didn't fit, I was young and hot headed and they were saddled by tremendous debt and the fact that too many of their assets were declining in value...it was really tough for them...I feel a little bad about my attitude then, I gather one Altec exec committed suicide because of all the financial issues they were facing...I don't think I could have made a bit of difference, but still have regrets and wish I could have...

Did house audio at Crazy Mama's in Columbus......new wave/punk place...Black Flag, David Johansen, Craamps, Joann Jett acts like that...oddly enough that place also did a lot of 50's-60's stuff...did Steel Pulse there...great band, wonderful people...

My ears still hurt from doing the Ramones in a tiny room....

Second most interesting show? Hard to say...Gotta tie between David Thomas and the Pedestrians, Sun Ra, and Fabulous Thunderbirds...how can I pick one over the other?


By late 70's/early 80's I was off the road managing the retail operation for one of the bigger local music stores...should have just stayed there...

Wanted to try something different, so I got out of audio around 84 to run a local entetainment publication...never made any money...nice status job, you can get tons of free drinks and food, so it was fun for a while...by 90 was out of that...just got boring...and I got burnt out with deadlines...

Since then mostly audio rentals, made more income cross renting than doing concerts myself...I retired about 6 years ago.

I still help out a local musician's school occasionally. But really don't do much except putz around.

Least path of resistance is out my back door...a quarter mile walk to a nice stream...most of the fish are too small to keep, occasionally net a good one or two.


I can help a lot with issues on 70's 80's gear if anybody needs it...I worked with a lot of that cantankerous stuff and know some of it's issues...and since I was doing retai I know some of the history of the guitar amp companies and stuff back then..

I like reading about DIY projects and stuff, would like to do more - I miss those old days...but lots of times it's easier to go fishing...got a favorite shade tree, that and a good science fiction novel I'm all set...SF not Sci-Fi BTW, there is a difference...at least to us wannabe writers....

Sorry didn't mean to prattle on, but you did ask...

[mech986]

Hi Old Guy,

Thanks for sharing your stories, makes me wonder what I missed. I was the AV kid in grade school spinning records at the 6th grade dance (cause I couldn't dance a lick...). Now do sound for my church as a volunteer.

Have you ever tried Science Fiction audiobooks? Although I enjoy reading, my old eyes are not as good as before. I really enjoy hearing either the author or an actor reading/playing the book before me. I'm quite partial to Star Trek audiobooks because there are tons of them read by many of the series actors. Give it a try if you have an mp3 or Ipod player.

[Steve Schell]

Old guy, I'm sorry to hear of your recent troubles. Are you the Old Guy of Unofficial Altec Board fame?

Bart, you got it exactly right on the titanium diaphragms. They were a solution to the problem of tearing aluminum 'phragms when things started getting loud. Folks at JBL have freely discussed their sonic shortcomings in the past. They have a relatively poor stiffness to mass ratio, and produce a number of breakup modes in the passband, generating that constant "tsss, tsss" sound that has kept me out of movie theatres for years. Somebody please let me know when they're gone.

The late John Eargle explained how aluminum has a "memory" of how many times it has been bent back and forth. It eventually work hardens and tears, usually at the outer edge of the suspension. Titanium apparently has no such memory, and can be flexed a virtually infinite number of times within its limits without failure.

Doug Button once showed us an FEA animation of a 4" titanium diaphragm operating at 14kHz. It had broken up into a large number of concentric ripples extending from center to edge. Then he showed an animation of a beryllium diaphragm operating under the same conditions and it was still operating as a nearly perfect piston, with only the barest hint of an incipient breakup mode. Piston motion at 14k... that ain't bad!

A friend of mine used to work closely with the late Jonas Renkus. Mr. Renkus designed many compression drivers, and was always in search of what he termed "direct reproduction of signal energy", i.e. not exploiting diaphragm misbehavior to attain measured high frequency response. Beryllium is currently the favored material to achieve this, with good reason. Personally I like carbon fabric composite diaphragms, but that's another story...

[neanderthal]

In a recent conversation of knowledgable folk on another forum, one person described the sound from compression drivers with titanium diaphragms as the classic ice pick to the forehead sound.

I never really found them to be harsh or outwardly forward but I suppose I enjoy horns in general but I beleive many do not.

...anyway, I suppose this is an amusing description by one who does not.

I never got an ice pick to the head but when I was 10 and my brother was 7 he threw a knife at me and it went through the eye lid and above the eye ball.Does that have enough status as an ice pick to the forehead?
Probably payback for the time I tried to throw a knife at him and stick it in his back. Fond memories of the good 'ol days...yes we use to play real hard back then and the police knew us well, now all the cops are retired and we're old,mellow and responsible.:blah:

[mech986]

Hi Steve and 4313B,

Thanks for the information and reminders of the Ti situation. For us who are still using the original 242x and 244x drivers, the aquaplassed diaphragms are probably going to be the best option if the plain Ti seems to be hard to listen too.

IIRC, the 2450SL/2451SL/2452SL are the aquaplassed 4" diaphragms. I can't recall which of the 242x diaphragms have aquaplass or we would have to seek out a provider for that service to existing diaphragms.

When I put my 4435's back together, I intend to try this out. Anyone know if a aquaplas diaphragm exits for the 2416H-1 as used in the 4425?

Bart

[4313B]

Beryllium is currently the favored material to achieve this, with good reason.:yes:

2435HPL $1,399
D8R2435 $756

**********

Oh wait!

Poor Speaker Repair (http://www.speakerrepair.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=10-287&Category_Code=l_jbl_dias) needs to stop buying their diaphragms from JBL and start buying their diaphragms from LA ZONA LIBRE (http://stores.ebay.com/LA-ZONA-LIBRE)

They routinely sell 2435HPL's for around $200 each too. :rotfl: :applaud: :rotfl: That's $1,200 off retail folks so get 'em while they're hot (no pun intended)


JBL PRO 2435HPL 1.5" EXIT SERIES COMPRESSION DRIVER (#370182596586)US $205.50

JBL PRO 2435HPL 1.5" EXIT SERIES COMPRESSION DRIVER (#220388987705)US $205.50

JBL PRO 2435HPL 1.5" EXIT SERIES COMPRESSION DRIVER (#220410013517)US $237.50

JBL D8R2435 Replacement Diaphragm for VERTEC 2435HPL (#220410206731) US $162.50

JBL PRO 2435HPL 1.5" EXIT SERIES COMPRESSION DRIVER (#370198100336) US $251.50

JBL D8R2435 Replacement Diaphragm for VERTEC 2435HPL (#220410206884) US $157.50

JBL PRO 2435HPL 1.5" EXIT SERIES COMPRESSION DRIVER (#220397479115) US $229.51

JBL PRO 2435HPL 1.5" EXIT SERIES COMPRESSION DRIVER (#220397478720) US $206.00

JBL PRO 2435HPL 1.5" EXIT SERIES COMPRESSION DRIVER (#370173694317) US $255.00

JBL PRO 2435HPL 1.5" EXIT SERIES COMPRESSION DRIVER (#220378445891) US $255.00


JBL needs to start buying from them! :yes:


Thanks for the information and reminders of the Ti situation. For us who are still using the original 242x and 244x drivers, the aquaplassed diaphragms are probably going to be the best option if the plain Ti seems to be hard to listen too.Yeah, that's exactly what Greg recommended, oh, let's see now, at least ten times in how many threads!? :hmm: Of course he also coats the berylliums since his philosophy has been "if it moves, coat it" (upgraded from "if it's metal, coat it").


What I've learned is that everyone thinks the aluminum diaphragms sound better until they have to put out $568 for a pair of new ones. Then they suddenly think titanium at $276 a pair sound just as good.Oops! My bad! :rotfl: Joke's on me! :D

JBL D16R2425 Replacement Diaphragm for 1" Driver, New (#370151334433) US $76.00

JBL D8R2425 Replacement Diaphragm for 1" Driver, New (#370165485199) US $57.00

JBL D8R2425 Replacement Diaphragm for 1" Driver, New (#220368834802) US $59.00

JBL D16R2441 Replacement Diaphragm for 1.5 & 2" Driver (#370173691621) US $91.70

JBL D16R2441 Replacement Diaphragm for 1.5 & 2" Driver (#220378443845) US $80.68

JBL D8R2425 Replacement Diaphragm for 1" Driver, New (#220389005092) US $55.55

JBL D8R2425 Replacement Diaphragm for 1" Driver, New (#370182605439) US $61.00

JBL D8R2425 Replacement Diaphragm for 1" Driver, New (#370182606401) US $53.00

JBL D8R2425 Replacement Diaphragm for 1" Driver, New (#370182611045) US $53.00

[old guy]

Old guy, I'm sorry to hear of your recent troubles. Are you the Old Guy of Unofficial Altec Board fame?


Guilty

Good to see you again

Steve somewhere in the back of the fog is a conversation about you and a business venture?

[Robh3606]

Poor Speaker Repair (http://www.speakerrepair.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=10-287&Category_Code=l_jbl_dias) needs to stop buying their diaphragms from JBL and start buying their diaphragms from

Yeah well whoever wins the 2435 diaphram is in for a surprise. You will not be able to close the drivers as they are. That's why they are for sale at that price.

Rob:)

[old guy]

Yeah well whoever wins the 2435 diaphram is in for a surprise. You will not be able to close the drivers as they are. That's why they are for sale at that price.

Rob:)

I would be a little afraid of that place...they have a low end mixer up at buy it now claiming it lists at $1200, demo unit $600...

Reality is it lists at $779 and regular net price is 600...so it's no discount at all for a demo unit...

http://www.sixstardj.com/prm220inmiwi.html


It's a l unit I wouldn't buy anyway...but I don't approve of misinformation in business...

[old guy]

Question for those a bit more engineering savvy..I'm more of a mechanic than engineer...

Does anybody know of any attempts to use PVA to damp diaphragms? Seems like it could be airbrushed, my limited acquaintance with it (mold release for fiberglass parts) it certainly looks like a good material...

Just curious, probably a total loss as an idea...

[JBL 4645]

The only thing that came close to an ice pick is the sound of the phasers at the Empire last month! Good God they where frigging loud I swear I could almost feel the HF ice picking at my forehead. I’d like to see what the HF is playing at when it comes out on DVD.

I’ll check the list again to see what HF there using as its tri-amp five-screen JBL speaker array.

Edit:

JBL 4732-T HF 115 dB SPL Part of the 4732 three-way only the bass cab is 4642A

[loach71]

The only thing that came close to an ice pick is the sound of the phasers at the Empire last month! Good God they where frigging loud I swear I could almost feel the HF ice picking at my forehead. I’d like to see what the HF is playing at when it comes out on DVD.

I’ll check the list again to see what HF there using as its tri-amp five-screen JBL speaker array.

Edit:

JBL 4732-T HF 115 dB SPL Part of the 4732 three-way only the bass cab is 4642A


Possibly a very badly done room equalization...

[robertbartsch]

The use of Ti frams which started 20-30 years ago seemed to have the impact of extending the UHF but some folks have always complained that they sound harsh.

I suppose, one solution to this is to add a UHF tweeter and x-over such as a 2405/077, 2402, etc. I used this technique a few times with success.

Since the alumium frams tend to roll off high up in the freq. range, the addition of an UHF tweeter is often necesary in many cases anyway.

[Doc Mark]

Well, we have to remember what the Ti diaphragms were supposed to do. When JBL researched and then introduced them, they were created in response to the problems with the Aluminum and dural diaphragms in use then - namely, limited lifespan, especially with the advent of higher power and SPL requirements, relatively older voice coil technology including adhesives and power handling, and the need to create a tougher and more durable diaphragm that could meet the prevailing sound requirments.

My understanding is when JBL got into the portable sound and higher SPL touring and Cinema markets, they started to see all kinds of failures that indicated the aluminum parts, while sounding great, had reached the limits of their design. Trying to find a compatible yet tougher material while holding down the cost efficiently led them to Ti.

They introduced the smooth Ti diaphagms and further development and research indicated the metal dome resonances were a problem. The diamond surrounds and then the ribbed pattern domes were an effort to tame and harness those resonances to extend the frequency response while maintaining the desirable characteristics of Ti. All of this was done over 2 decades while thousands of speakers were in operation daily in venues all over the world. JBL was responding to their needs as well as looking out for their product warranty issues.

I think JBL would acknowledge that the Ti diaphragm, like all products, has its plusses and minuses. With renewed effort from Harmon and push from the engineers, the newer Aluminum and now Be diaphrams are further signs that JBL continues its research and push for the best products out there. Yes, they do cost a fair amount but what newer and better technology doesn't have its development costs that must be recovered.

Some would say that the Ti phragm can also be tamed somewhat with judicious EQ at the top end. Others don't care for them - that's ok. If one understands what they are for, each can pick the pieces that they like.

I'm glad that JBL can provide so many different choices for so many markets. I've always wondered what a Vertec Array might sound like in my living room!!

My 0.02, your mileage may vary.

Regards,

Bart

Morning, Bart,

Your comments are right on the money, and well stated! Thanks, very much, for your insightful take on all this. Take care, and God Bless!

Every Good Wish,
Doc

[4313B]

Your comments are right on the money, and well stated! Thanks, very much, for your insightful take on all this.I'm pretty sure he read it all here during one of the at least ten other rehashes of this subject.

Here's the good stuff:

http://audioheritage.org/vbulletin/showpost.php?p=25545&postcount=46

http://audioheritage.org/vbulletin/showpost.php?p=25549&postcount=15

http://audioheritage.org/vbulletin/showpost.php?p=29798&postcount=31

http://audioheritage.org/vbulletin/showpost.php?p=128507&postcount=116

[Titanium Dome]

The SAM1HF has an Al HF driver and a Ti UHF driver. :spchless::shock::spchless:

OMG, JBL defied the conventional wisdom of this thread!! It's totally backward.:help:

[Mr. Widget]

The SAM1HF has an Al HF driver and a Ti UHF driver. :spchless::shock::spchless:

OMG, JBL defied the conventional wisdom of this thread!! It's totally backward.:help:No, they put the aquaplassed aluminum diaphragm right where it could do the most good!

As for the tweeter, they made an educated design decision and chose Ti to save money. If they had used Mg or Be, the HF would certainly be better and more costly... I won't guess why they didn't use AL for the 045, but they determined Ti was the best answer at that price point.

I have heard the Ti and Be versions of the 045. The beryllium version is without question far superior sounding... however it is also far costlier. I am not sure I would notice the difference during a musical performance presented in surround with an accompanying image up on the screen. Maybe I would, but I wouldn't bet my life on it. ;)


Widget

[Titanium Dome]

Well, then, since we're so focused on the best possible sound, JBL should put Be drivers in all their lines and just charge the difference. Most people here would pay it, I bet. :no: :p

Those of us who are complacent about it would just muddle through with our cheap Ti drivers.

[mech986]

I'm pretty sure he read it all here during one of the at least ten other rehashes of this subject.

Here's the good stuff:

http://audioheritage.org/vbulletin/showpost.php?p=25545&postcount=46

http://audioheritage.org/vbulletin/showpost.php?p=25549&postcount=15

http://audioheritage.org/vbulletin/showpost.php?p=29798&postcount=31

http://audioheritage.org/vbulletin/showpost.php?p=128507&postcount=116

Hi 4313B,

True, knowledge gained and remembered, although I'm not sure I saw all the threads above. But have read them fully now :applaud:

Can you also quote for us the 4th thread? I can't access that thread like you can, would love to see what was discussed there too.

Regards,

Bart

[4313B]

Can you also quote for us the 4th thread? I can't access that thread like you can, would love to see what was discussed there too.Sure, here it is:



I am no expert, but doesn't that peak at 9KHz represent a break up mode? The 476Be has it's first break up mode beyond 20KHz... as far as I know nothing from TAD can match that, and the two TAD drivers I have tried are subjectively grainy at the top end. The 476Be would appear to be in a league of it's own. I'd stay with the 435Be/045Be until something at the level of the 476Be could be obtained.

Widget


I'm pretty sure that 9khz does actually represent the first breakup mode. I'm not sure where the assertion that the 476Be does not break up until 20khz came from. It definitely extends to 20khz, after which the limits of the phase plug geometry causes a hole in the response immediately above that frequency.

In comparison, the 435Be has its first breakup mode at 16khz. The smaller 3" diameter of the driver diaphragm is one of the main reasons for its extended pistonic response. Doug Button specifically chose the smaller diameter just to ensure that the entire design bandwidth was reproduced without breakup. For everything else being equal, a larger diaphragm is not as strong as a smaller one just due to geometry and will therefore breakup at a lower frequency. Using less stiff materials, such as aluminum and titanium, means that breakup modes occurred as low as 4khz in the 4" diaphragm 375, 2445 and 2446 etc. From what I understand, I don't think it is possible to construct a 4" diameter beryllium diaphragm that is pistonic up to 20khz without having it weigh so much that efficiency and mass rolloff issues would make it impractical.

Don

[herki the cat]

speakers Speakers
Funny, upon auditioning speakers recently my wife and I listened to Maggies and they have a definate shrill resonance in the treble, more subtle than the spikes in a Klipsch Heresy but most certainly there. After a few minutes they were setting my teeth on edge and giving my wife an earache.

Yet unlike horns Maggies are "audiophile approved" and people are free to interpret the resonance as increased detail.

There realy isn't much choice. This "tizzi, high Q Resonance is inherent in nearly all modern Electro - Static Speakers, Professional Studio Microphones, & Electro - Magnetic Panel Speakers which now use Mylar Film diaphragms exclisively :banghead: .

Mylar is very durable & mechanicaly stable, but it sorely lacks the clean, lovely "Sheen" of the transducer diaphragms popular prior to the 1960's, AKA in the Quad Speakers, & other Electrostatic speakers, as well as the original classic Magna-planars.

The highly sought - after pre 1960's "Telefunken U-47 Studio Microphone" :applaud: manufactured by George Neumann in Germany, used a Poly Vynal (3) micron, (1) inch diaphragm which was made by pouring the Poly Vynal in liquid state on a rotaring (1) inch dia' round optical glass disc__ spinning to flow off the excess plastic compound until the film was reduced to (3) micron thickness. A tiny short plastic cylinder was then cemented to the perifery of the diaphragm while it was still flat on the round glass disc to form a precison (can-like)assembly which could be slipped & clamped onto the mcrophone capsule body.

:bouncy: RCA, :bouncy: in the 1930's, produced dynamic microphones with diaphragms made of polystyrene as well as aluminum. there were many other benign, very good plastic films from the 1930's on.

[robertbartsch]

I have nothing against Altec and I have enjoyed a VOTT system for 30+ years. In fact, for natural reproduction the Altec aluminum framed compression driver is still my favorite.

That said, I think one short comming that helped hasten Altec's demise included drivers that did not hold up well under extreme conditions like sound reinforcement applications. Dispite their tendency to be harsh at higher frequencies, Ti frams seem to fit the bill of being very ruggid and reasonably priced.

The addition of an UHF tweeter in many cases eliminates the harsh "tsss" sound from Ti frams. I'n not sure why they eliminated the production of the 2405s and 077 slots, but they are still around in abundance.

[JBL 4645]

THEATER SOUND

[quote=Steve Schell;256420]Old guy, I'm sorry to hear of your recent troubles. Are you the Old Guy of Unofficial Altec Board fame?
Bart, you got it exactly right on the titanium diaphragms. They were a solution to the problem of tearing aluminum 'phragms when things started getting loud. Folks at JBL have freely discussed their sonic shortcomings in the past.

They have a relatively poor stiffness to mass ratio, and produce a number of breakup modes in the passband, generating that constant "tsss, tsss" sound that has kept me out of movie theatres for years. Somebody please let me know when they're gone.


MY TWO CENTS
Me Too! I can not stand the poor speech intelligibilite since the gorgeous low frequency horn mid bass spectrum went bye, bye :banghead: Those lovely :applaud: "W" Bins, the MI-9462 Ubangis, & Altec 210's. There is nothing there for the high frequency horn to hand over in the fundamentals spectrum.

The poor damping of the high-frequency horn FS honk originaly ameliorated by the midbass quality of the low frequency horns, the poor solid state amplifier damping factor & the excessive sound SPL recomended by THX result is a disaster.

However, JBL now has a new three way theater speaker system with a new mid range horn which I am very anxious to hear.

cheers, Herki

I think there is only few in the L.A. area that have three-way JBL.
Maybe a few in New York needle in haystack.

[Ducatista47]

The addition of an UHF tweeter in many cases eliminates the harsh "tsss" sound from Ti frams. I'n not sure why they eliminated the production of the 2405s and 077 slots, but they are still around in abundance.

A reason I have heard several times was the high cost to fabricate them. When cheaper ways to satisfy the requirement are available, say bye-bye. Besides, almost fifty years is not a bad run for any transducer.

As much as I love them, it always did seem a lot of magnet for a tweeter. Old school, like me.

Clark