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PostPosted: Tue Nov 03, 2015 4:23 pm 
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Location: Oakley, CA, US
One of the factors in choosing a speaker is the fatigue life of the Driver materials. I don't believe paper or plastics are good choices unless you're buying a very inexpensive speaker. Always ask the seller or dealer for the materials used before investing $1,000.00 or more. My opinion is, of course, stay away from those materials altogether. This is one reason I recommend JBL.

The fatigue life of materials depends on amplitude of deflection. There is also a threshold. Meaning that if a diaphragm never sees more than a certain level it will never fatigue.

It was felt that these diaphragms (aluminum) would probably last 2 hours at full power before starting to crack. The derating we believe to be that the life will extend about 10 times for each halving of power.

The whole thing is of course complicated by spectrum. The above assumes the 2" drivers crossover around 1,000 Hz and the 4" drivers about 500 Hz.

Titanium has about 10 times the fatigue resistance of aluminum. However the threshold is much higher as far as never fatiguing. Aluminum continues to fatigue at very low levels.

The stress in the diamond surround is higher and thus would fatigue easier.

The basic improvement of the diamond surround is that it moves the second resonance way up to 17,000 Hz or more. So they are simply broader band.

This is one way of guaranteeing getting your money's worth and the . . .

Bestsound


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PostPosted: Sat Nov 07, 2015 8:20 pm 
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Location: Etobicoke, ON, CA
Most audio buffs I have met tend to tire (become fatigued) with their loudspeakers long before their drivers show signs of fatigue.

BTW: Last time I checked, JBL was still using paper cones.

prosoundman


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PostPosted: Tue Nov 10, 2015 4:41 am 
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Joined: Tue Jul 05, 2005 3:09 pm
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Location: Sherbrooke, QC, CA
I am fatigued by your rather seemingly pointless posts.

Although you may have found a route to the logical conclusion about break-in.

Maybe you should work on that line of logic... maybe.

:)


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PostPosted: Tue Nov 10, 2015 9:27 am 
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Prosoundman wrote:
Most audio buffs I have met tend to tire (become fatigued) with their loudspeakers long before their drivers show signs of fatigue.

BTW: Last time I checked, JBL was still using paper cones.

prosoundman


The last time you checked? Perhaps you mean the late 1970's to early 1980's in their tweeters; e.g. L-100's. So, apparently your "checking" isn't very current. After the early 1980's JBL gave up pure paper drivers in favor of using a plasticized/coated paper "base" called Aquaplas - - or pure plastic altogether in their lesser expensive speakers; e.g., their J and L series like their L-20T speakers - - but let me stress here again that pure paper (due to early fatigue) hasn't been used since before the "Golden Age" of Audio. Actually, While I did mention "drivers" generally (which could be bass, mids, etc.) I was actually attempting to zero in on tweeters. Aluminum and Titanium is a far, far better choice of materials for tweeters rather than paper, and JBL learned that decades ago. There are some manufacturers new to the business that are still using paper and/or plastic! I imagine they feel the money saved on materials is better placed in their pockets! How do these manufacturers have the audacity to charge such huge sums for their speakers when using materials that JBL learned years ago were not as good sounding?

But, I am very proud of the fact that my "White Paper" was so controversial for you that it actually made you write a comment for the FIRST TIME since you originally joined in August of 2008 - - and for that, I am grateful and yes, proud to have woken you up!!

Bestsound


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PostPosted: Thu Nov 12, 2015 10:41 am 
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Joined: Tue Nov 05, 2013 8:49 am
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Location: Hudson, NH, US
Bestsound,

The conclusions that you come to make some sense, but not for the reason that you stress (pun intended), I believe.
Having been in the professional audio repair business for some time now, I have repaired my share of
blown speakers. The most common failure mode by far is overheating of the voice coil which leads to
warping/deformation/rubbing of the moving elements. Metals have far better heat transfer than paper
or plastic. Metal cones or domes radiate away some of the thermal energy developed in the voice
coil. And in that regard, aluminium is preferred to titanium.

BTW - there are still many, many intact drivers in older speaks that are made of paper, felt, and/or fabric,
that are still functioning after decades of service.


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PostPosted: Thu Nov 12, 2015 12:17 pm 
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Joined: Sun Jan 06, 2008 10:58 pm
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Location: Laval, QC, CA
Hey,


Small question, Bestsound, no offense: are you a JBL fan ?

PS: By the way, I never meant to sound malicious or anything similar...


Last edited by ez4unm on Fri Nov 13, 2015 11:35 am, edited 1 time in total.

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PostPosted: Thu Nov 12, 2015 12:49 pm 
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Location: Oakley, CA, US
fourchords wrote:
Bestsound,

The conclusions that you come to make some sense, but not for the reason that you stress (pun intended), I believe.
Having been in the professional audio repair business for some time now, I have repaired my share of
blown speakers. The most common failure mode by far is overheating of the voice coil which leads to
warping/deformation/rubbing of the moving elements. Metals have far better heat transfer than paper
or plastic. Metal cones or domes radiate away some of the thermal energy developed in the voice
coil. And in that regard, aluminium is preferred to titanium.

BTW - there are still many, many intact drivers in older speaks that are made of paper, felt, and/or fabric,
that are still functioning after decades of service.




[/quote]BTW - there are still many, many intact drivers in older speaks that are made of paper, felt, and/or fabric,
that are still functioning after decades of service.[/quote]

fourchords:

Agreed; there are always exceptions. There are still 14 window V.W. Transporters out there running someplace in the world, too. When it comes to Aluminum and Titanium however, they not only last the longest, but they also sound far better (in my opinion, and that of Greg Timbers). So, there are always exceptions to the rule; and from a "cost to build" standpoint, I think we can all agree that metal tweeters cost far more to manufacture. But, what really grinds my gears is when I see hyper expensive speakers that are nowhere near the quality of older speakers; e.g., JBL Ti series, then I get a feeling that the "paper" cone manufacturers are just pocketing the money (read this as "greedy") and when you ask them how they come up with their own MSRP, it a bit like the fox guarding the hen house and they have no solid reasoning for such outrageous prices when the parts they use, and the design characteristic they employ, are certainly cheap. Ask them for the thickness of their wiring, the brand of parts for their cross-overs, the thickness of their wood cabinets, and the list goes on and on, and what we find is a speaker that's not even "pretty" to show off in your home and can't give good reasons for being so expensive. Remember in my first post I mentioned PLASTIC tweeters? How can that EVER qualify for expensive when compared to the overall price of the speakers? Let's be realistic, and not greedy. Some of today's speakers don't even qualify for being as "expensive" as Pioneer or their ilk, yet we see two-ways for near $2,000.00!!! Someone's trying to buy a Ferrari.

Yes, I am (was) a huge fan of JBL, having been so for decades, and proud of it - - since 1965 to 1992. After 1992, the company has, well, "died" as far as I'm concerned, when they muddied their name with low end junk like the "J" series and the "Northridge" series. JBL used to mean something when their
low end was the "L" series (which wasn't so "low end"), and today, there's a lot to be desired - e.g., "Ear Buds" and "WalkAround" music. Let Sony do that crap. Can you imagine "Sonus Faber" and their ilk doing "Ear Buds"???. JBL's high-end "S" series and "Everest" series, etc., have, thank God, been maintained as "High End." And now, JBL has shot itself in the foot by letting Greg Timbers go. Now, my next big problem will be, "Who will be the next JBL?" I guess the answer to that question will be, "Whomever hires Greg Timbers" will be the next "Big Gun" in the town.

Bestsound


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PostPosted: Thu Nov 12, 2015 12:52 pm 
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Joined: Sat Jun 23, 2012 9:12 am
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Location: Windsor, CO, US
Another factor not touched on in his "white paper" is the environment. The environment plays a huge part in material fatigue.

Salt in the air if you live near the coast. Humidity and temperature extremes. Damp and dry areas.

Not sure what your unnatural attraction to JBL is? I was a JBL dealer for 25 years. Yes, they make some good value speakers, but are not the end all be all of manufacturers.

I know you really like the Ti series of JBL speakers. We couldn't give those away when they were first introduced. The titanium tweeters were so bright that customers hated them.

Have you had your hearing tested lately? Just asking because I bet it is down 4db-6db above 12khz or so. That's probably why you like the Ti series so well. Not a dig at you, just wondering.

_________________
"Did I listen to pop music because I was miserable? Or was I miserable because I listened to pop music?"
-Rob Gordon-


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PostPosted: Thu Nov 12, 2015 1:24 pm 
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MrAudio wrote:
Another factor not touched on in his "white paper" is the environment. The environment plays a huge part in material fatigue.

Salt in the air if you live near the coast. Humidity and temperature extremes. Damp and dry areas.

Not sure what your unnatural attraction to JBL is? I was a JBL dealer for 25 years. Yes, they make some good value speakers, but are not the end all be all of manufacturers.

I know you really like the Ti series of JBL speakers. We couldn't give those away when they were first introduced. The titanium tweeters were so bright that customers hated them.

Have you had your hearing tested lately? Just asking because I bet it is down 4db-6db above 12khz or so. That's probably why you like the Ti series so well. Not a dig at you, just wondering.


Mr. Audio:
No offense. It's a valid question and observation. Ask a matter of "ipso facto" I did have my hearing checked 2 years ago by an Audiologist. Funny you should mention it. Believe it or not, for an old guy, my hearing is "impressive" according to the Audiologist. Way above what I should be hearing, at my age. I was impressed, also. However, my dog is getting sick and tired of me perking my ears up before he can!!

Anyway, I failed to mention that it has always been my belief that JBL gave their buyers their money's worth. The LE14 series of drivers are arguably some of the best ever low-end drivers ever; and, they were never too expensive (read that as "outrageously" priced") and made speakers sound very impressive. The overall price of JBL speakers were never crazy priced like some that are today. It's as if these manufacturers truly believe their 2-ways speakers are the most marvelous speakers ever made! While JBL was never the "best," they were very good sounding and I'll always argue that they were priced to give the consumer great "bang for the buck." We could go on all day long with the good points and bad points of every brand of speaker. I'm just saying that JBL had the greatest overall acceptance from consumers. Oh, and by the way, when it comes to recording studios, and forums, and any other place that uses amplification, JBL has a 75% rating. That's right - - JBL is in 75% of all sound venues of any type. So, in my opinion, while not the most expensive, JBL is the best for the money and they are everywhere! Not Yamaha, not Pioneer, not Peevey, not, not, not, not, not. It's JBL.

One last note. The build quality of the JBL Ti series was fabulous and withstood the most environmental situations than any other speaker - - ergo, that's one reason why they are in 75% of music venues. Have you ever looked at the cabinet bracing of the Ti series versus, say, the L series? How about the cabinet thickness? How about the wiring size? How about their magnet sizes?, How about their voice coil sizes?, how about, how about, how about . . . The better reason they had a hard time being sold was that the Ti series were very expensive versus the L series, and their target audience were the 18 to 24 year olds - - and simply, that "target" couldn't afford them. By 1988, however, the entire build quantity were sold; i.e., not a pair of Teak Ti speakers could be found at a dealership. Yes, it took years to sell them all, but it was finally done. The L series sold like hotcakes because the "target" could afford them, and the "target" didn't care about Build Quality. The "target" wanted music, and in those days, the recording quality didn't matter. Today, DDD sounds so much better on Ti speakers than L series speakers. But, it was the L series that they "grew up on" and it was the L series that kept JBL afloat - - thousands and thousands and thousands were sold versus a few of the expensive Ti speakers (I have actual copies of the "Confidential Dealer Cost Sheets" of both the L series and the Ti series)

Bestsound


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PostPosted: Mon Oct 10, 2016 10:03 am 
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Joined: Mon Aug 29, 2016 5:23 am
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Location: Canaan, CT, US
If a metal is not driven past its elastic limits and not subjected to corrosive elements it should have a long lifespan.

Unfortunately many manufacturers do not take this factor into account.

I agee with the person that said above that many change speakers before such conditions come into play.


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PostPosted: Thu Sep 07, 2017 11:50 am 
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Location: East Dorset, VT, US
While a fan of JBL. it's the man, not particularly the company. You are confusing me, however. I have seen only one tweeter with a metal surround, and it's just a supertweeter. How in the world can one make a diamond surround? Or is this a line name? A diamond dome I can comprehend, but the surround?
As to cone/dome materials, I consider crossover requirements, usage environments, and potential uses/abuses. Sometimes we are forced to use a rather complex circuit because we need a certain material to handle a situation.
I have no problem with obvious eventual maintainance requirements. Too often people are fooling themselves, as with the common foam/cloth/rubber surround issue with mids/woofers. They all deteriorate in different ways and require replacement/cleaning and redoping/devulcanising and ultimately replacement. The compliance of all will change and affect the parameters. In one way, the foam surround is good,as it will shout HELLO! and disintegrate on you(hopefully you catch it before you bang the voicecoil).
If you have links I can follow regarding materials that have worked for you, I will certainly read them.

best, David


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PostPosted: Thu Sep 07, 2017 2:14 pm 
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Location: Portland, OR, US
Of course, the durability of driver materials is unrelated to the sound quality of those same materials. Metals having poor self-damping and some metal diaphragms showing high amplitude, high Q resonances. That is not to say that some cannot sound quite good.

My vacuum tubes, phono cartridge and the electrolytic capacitors in my electronics will reach end of life long before my loudspeakers.

If one used this same logic to purchase autos we would all drive Sherman tanks.


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PostPosted: Thu Sep 07, 2017 4:36 pm 
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Well, a friend of mine has a '72 mercedes 240 diesel, manual everything. The starter,lights,radio, and wipers are the only electric items. But now that he is eighty or so, the manual steering is a chore.
So we can get a little carried away. There's no avoiding tires, wipers, brakes, seat cushions, etc. I think it's like a marriage, you have to pick your fights, let other stuff go. But it's fun to watch someone push the envelope sometimes, see how far they get.

best, David


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PostPosted: Wed Sep 13, 2017 2:17 pm 
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Location: Repentigny, QC, CA
Quote:
We couldn't give those away when they were first introduced. The titanium tweeters were so bright that customers hated them.


+1

Now that I believe.


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