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

  1. #31
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    Quote Originally Posted by boputnam View Post
    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....

    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...

  2. #32
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    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.
    When faced with another JBL find, Good mech986 says , JBL Fan mech986 says

  3. #33
    Senior Member Steve Schell's Avatar
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    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...

  4. #34
    RIP 2011 neanderthal's Avatar
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    ...ever get an ice pick to the forehead?

    Quote Originally Posted by robertbartsch View Post
    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.

  5. #35
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    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
    When faced with another JBL find, Good mech986 says , JBL Fan mech986 says

  6. #36
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    Quote Originally Posted by Steve Schell View Post
    Beryllium is currently the favored material to achieve this, with good reason.


    2435HPL $1,399
    D8R2435 $756

    **********

    Oh wait!

    Poor Speaker Repair needs to stop buying their diaphragms from JBL and start buying their diaphragms from LA ZONA LIBRE

    They routinely sell 2435HPL's for around $200 each too. 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!

    Quote Originally Posted by mech986 View Post
    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!? 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").


    Quote Originally Posted by 4313B View Post
    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! Joke's on me!


    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

  7. #37
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    Quote Originally Posted by Steve Schell View Post
    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?

  8. #38
    Administrator Robh3606's Avatar
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    Poor Speaker Repair 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
    "I could be arguing in my spare time"

  9. #39
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    Quote Originally Posted by Robh3606 View Post
    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...

  10. #40
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    Question about fram damping?

    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...

  11. #41
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    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

  12. #42
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    Quote Originally Posted by JBL 4645 View Post
    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...
    Amazed I'm still alive!
    Tim

  13. #43
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    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.

  14. #44
    Senior Member Doc Mark's Avatar
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    Quote Originally Posted by mech986 View Post
    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
    The only thing that can never be taken away from you, is your honor. Cherish it, in yourself, and in others.

  15. #45
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    Quote Originally Posted by Doc Mark View Post
    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/s...5&postcount=46

    http://audioheritage.org/vbulletin/s...9&postcount=15

    http://audioheritage.org/vbulletin/s...8&postcount=31

    http://audioheritage.org/vbulletin/s...&postcount=116

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