Alnico Magnets in the K2's?

[oznob]

I was browsing the JBL site and looked at the specs of the K2's. To my surprise, it lists the woofers as 15" with Alnico magnets. I thought they quit using Alnico years ago. Is this accurate and, if so, why Alnico and not Ferrite? :confused:

[Titanium Dome]

Go back to the JBL site and check out this page:

http://jbl.com/home/k2_story/default.aspx

Click on the 1500AL link for info on the AlNiCo.

[Don McRitchie]

http://www.audioheritage.org/html/projectmay/technology/1500al.htm

[hapy._.face]

http://www.audioheritage.org/vbulletin/showthread.php?t=9727&highlight=1500AL

[toddalin]

I was browsing the JBL site and looked at the specs of the K2's. To my surprise, it lists the woofers as 15" with Alnico magnets. I thought they quit using Alnico years ago. Is this accurate and, if so, why Alnico and not Ferrite? :confused:

Obviously, as anyone with vintage JBL equipment can tell you, Alnico just sounds better, so where cost is no object, may as well use the best!:D

[hapy._.face]

Obviously, as anyone with vintage JBL equipment can tell you, Alnico just sounds better, so where cost is no object, may as well use the best!:D

...Well, that's one good way to spark a debate! :bouncy:

[edgewound]

Ever notice that the JBL "Statement" systems are named after mountains in Asia?. Why do you think that is:hmm: ;) ?

[4313B]

...Well, that's one good way to spark a debate! :bouncy:There is no debate. He's ignorant of the facts. We've been over this ad nauseum. There's always some uninformed soul who has to stand up and yell out that the old alnico V crap from the legacy transducers was better. The 1500AL is AlNiCo done right! Hopefully they will do a 1400AL too, and hopefully it will make the same bass as an LE14H-3.

[oznob]

I think the old D130's are second to none when it comes to guitar amp speakers. For home use, the 2235's are very hard to beat!

[hapy._.face]

There is no debate. He's ignorant of the facts. We've been over this ad nauseum. There's always some uninformed soul who has to stand up and yell out that the old alnico V crap from the legacy transducers was better. The 1500AL is AlNiCo done right! Hopefully they will do a 1400AL too, and hopefully it will make the same bass as an LE14H-3.

Straight to the guts! That about sums it up. Well said.

[Ian Mackenzie]

Obviously, as anyone with vintage JBL equipment can tell you, Alnico just sounds better, so where cost is no object, may as well use the best!:D


There is no debate. He's ignorant of the facts. We've been over this ad nauseum. There's always some uninformed soul who has to stand up and yell out that the old alnico V crap from the legacy transducers was better. The 1500AL is AlNiCo done right! Hopefully they will do a 1400AL too, and hopefully it will make the same bass as an LE14H-3.


Oh come on , you loved your 4315's and you know it. :D

You've come a long ways since then as well.:applaud:

Its all relative, they were a shit load better than anything else at the time and besides what they were feeding into them was shit load back then anyways:blah: :blah: :blah: :blah: :barf:

[4313B]

Correct on all counts. ;)

[toddalin]

There is no debate. He's ignorant of the facts. We've been over this ad nauseum. There's always some uninformed soul who has to stand up and yell out that the old alnico V crap from the legacy transducers was better. The 1500AL is AlNiCo done right! Hopefully they will do a 1400AL too, and hopefully it will make the same bass as an LE14H-3.

Some people can't take a joke.:p

Still, people claim to be able to hear a difference between different types of wire, different capacitors, different cabinet shapes, etc. Thus, it seems pretty naive to think that the material that the magnet is constructed from has absolutely no effect on the sound. You just need more sensitive or different instruments to measure the difference.

[4313B]

Some people can't take a joke.:pThose bastages!
Still, people claim to be able to hear a difference between different types of wire, different capacitors, different cabinet shapes, etc. Thus, it seems pretty naive to think that the material that the magnet is constructed from has absolutely no effect on the sound. You just need more sensitive or different instruments to measure the difference.It absolutely does have an effect - read the white paper on it. Measurements in it for all as well. Some people really do like all that distortion those old alnico motors produced. There's nothing any of us can do about that. :p They were certainly fine at the time when that was all we had. Hence Ian's points. Reducing transducer distortion appears to be a very real goal at JBL.

[hapy._.face]

...people claim to be able to hear a difference between different types of wire, different capacitors, different cabinet shapes, etc

'Claim'!? Are you indicating you can't!? The differences are very real- and very audible. I'm sure you were just using that to make a point.....right? :o:

AlniCo (old school) is so sensitive and prone to damage that I (personally) wouldn't use it with a modern day amplifier unless it was all I had. Suffice to say- the reasons JBL picked up AlniCo in current production projects is a direct reflection on the advancement of the material and it's handling. AlniCo in its vintage state leaves a lot to be desired with regard to modern day high performance. These are facts, not opinions.

It does make for some good guitar cabinet speakers, though- but that is hardly a critical listening application.

[edgewound]

'Claim'!? Are you indicating you can't!? The differences are very real- and very audible. I'm sure you were just using that to make a point.....right? :o:




Some people can't take a joke.:p

Still, people claim to be able to hear a difference between different types of wire, different capacitors, different cabinet shapes, etc. Thus, it seems pretty naive to think that the material that the magnet is constructed from has absolutely no effect on the sound. You just need more sensitive or different instruments to measure the difference.




I do believe that Todd said it's naive to think that way...right Todd?

[hapy._.face]

I do believe that Todd said it's naive to think that way...right Todd?

Naive to think what way? ...that you can hear the differences (?)...or that you cannot?

I'm lost. First it was a statement about the superiority of Alnico, then that was supposed to be a joke. Let's all hit that pub we always talk about. text sucks.
:)

[toddalin]

I do believe that Todd said it's naive to think that way...right Todd?

Naive to think that it doesn't make a difference.

[MJC]

'
AlniCo (old school) is so sensitive and prone to damage that I (personally) wouldn't use it with a modern day amplifier unless it was all I had. .
I've got seven 112As that would prove that statement wrong. The 112H may have less distortion, but the 112 was the most expensive mid-bass driver that JBL made and still sounds better than most current drivers today.
In fact there are a lot of current HT speakers that could be greatly improved with the addition of a 112A or H

[hapy._.face]

I've got seven 112As that would prove that statement wrong. The 112H may have less distortion, but the 112 was the most expensive mid-bass driver that JBL made and still sounds better than most current drivers today.
In fact there are a lot of current HT speakers that could be greatly improved with the addition of a 112A or H

I'm not far behind in having owned six.

A reminder:

http://www.audioheritage.org/vbulletin/showpost.php?p=91149&postcount=51

This isn't about the 112 at all, it's about Alnico. However, since you brought it up- Have you ever A/B a 112A/112H?

[MJC]

I'm not far behind in having owned six. I quickly sold them all.

A reminder:

http://www.audioheritage.org/vbulletin/showpost.php?p=91149&postcount=51

This isn't about the 112 at all, it's about Alnico. However, since you brought it up- Have you ever A/B a 112A/112H?

No, I haven't compared a 112A to a 112H. But I do admit the 112H has less distortion, from what I've read.
The 112A IS Alnico so the 112A does come into the conversation, as would any Alnico speaker.
btw, I don't know where you got your info about the original price of the L212s. But it wasn't $5k for a system, it was only $2k.
And the 112 wasn't the only reason the L212s sold, I guess you forgot about the 066, which was used in many JBL models and lets not forget the B212.
But you like to run off at the mouth.

[hapy._.face]

But you like to run off at the mouth.

I guess when you have limited thoughts- you'll resort to trash like that. People sure do like to filthy up the place- a forum named after a great man- bearing his name and you talk like that.

You completely misinterpreted what I was saying, but rather than clarify- you go for the lowest common denominator. Looks like you're the only one running off at the mouth, here.

Perhaps I read it wrong, but the JBL price list says $2559.00 each in '77. If 'each' means a single, than it's $5K. If 'each' means a complete set, I got it wrong. So what.

I'm entitled to my opinions- right or wrong. I can blab them all I want. I'm not attacking anyone, calling anyone names, or anything of the sort. Deal with it. It's a FORUM. I'm following all the rules- more than I can say for others...

[MJC]

I guess when you have limited thoughts- you'll resort to trash like that. People sure do like to filthy up the place- a forum named after a great man- bearing his name and you talk like that.
.

I wasn't being rude, but since you joined in Jan you've got almost 600 posts. And I sure I haven't seen all of them. But I would guess that close to half wouldn't be considered even as one liners.

[hapy._.face]

I wasn't being rude, but since you joined in Jan you've got almost 600 posts. And I sure I haven't seen all of them. But I would guess that close to half wouldn't be considered even as one liners.

Of course you weren't being rude. I misinterpeted what you said, right? You just talk that way- even to your family and friends, is that it?
Well, I'd rather have 6 million posts under by belt in 6 minutes, so long as no one can quote me as saying 'running off at the mouth' on a forum dedicated to a dead man's legacy.

[Steve Gonzales]

I like your posts Happyface, you too MJC. Both of you seem to think highly of the L212 system. I think you should both cool down and start over.

[MJC]

Of course you weren't being rude. I misinterpeted what you said, right? You just talk that way to your family and friends, is that it?
Well, I'd rather have 6 million posts under by belt in 6 minutes, so long as no one can quote me as saying 'running off at the mouth' on a forum dedicated to a dead man's legacy.

Well I've seen a LOT worse comments, than the one I've made, on this forum. Sounds like you need a little thicker skin.

[Steve Gonzales]

Can anyone that owns, say, a pair of 4343's, L212's, 4311's, L300's etc, that are in good working condition, tell me that they are disappointed with their Alnico drivers?. I mean, if there is an improvement in technology that provides better performance Alnico these days, cool, but just because of that, I don't think I'll be selling off all my wonderful Alnico drivers, they still perform extremely good. Are you pleased with yours?.

[hapy._.face]

Well I've seen a LOT worse comments, than the one I've made, on this forum.

That doesn't make any of it right. Nor does it excuse your rude comments. But hey, maybe you are on to something here: When I go to a place that has litter on the ground- I can just throw my trash there, too. Right?


Sounds like you need a little thicker skin.

Wow! That's your logic!? So, if I called you and your wife ugly, and you are offended- I'll just follow up with a 'you need thicker skin', and 'I wasn't being rude'. That should rectify it, eh? Sounds like you need to learn some manners.

[Steve Gonzales]

Can anyone that owns, say, a pair of 4343's, L212's, 4311's, L300's etc, that are in good working condition, tell me that they are disappointed with their Alnico drivers?. I mean, if there is an improvement in technology that provides better performance Alnico these days, cool, but just because of that, I don't think I'll be selling off all my wonderful Alnico drivers, they still perform extremely good. Are you pleased with yours?. Answer if you can?:)

[hapy._.face]

Can anyone that owns, say, a pair of 4343's, L212's, 4311's, L300's etc, that are in good working condition, tell me that they are disappointed with their Alnico drivers?. I mean, if there is an improvement in technology that provides better performance Alnico these days, cool, but just because of that, I don't think I'll be selling off all my wonderful Alnico drivers, they still perform extremely good. Are you pleased with yours?.

This isn't a techwar, unless you are wanting one. Alnico rocked, and I'm sure it still can in the hands of capable techs. I said that I wouldn't use them unless I had to. That doesn't mean I think they are completely inferior- only that I would preserve them. I would worry about the loss of magnetic energy and such* while using a modern day amplifier. Alnico speakers used in guitar amps have already had the bejesus played through them, so they don't count, IMO. I can play those and I don't have to worry about the ill effect I'm having on them.

*I know they can be redone, but who wants that expense?

[Steve Gonzales]

Hey, I didn't mean techwar ,as in, you two going at it. I meant that with all the specs and numbers and such floating around, I just sit and LISTEN to my Alnico drivers and can't really translate the talk to the sound. I will not dismiss the fact that JBL is advancing technology, they're JBL, but, the older stuff makes me happy as I'm sure it does for thousands of owners of various models around the world. NEVER heard anyone say that they were not satisfied with a good working Alnico driver.

[scott fitlin]

I use six JBL 2441,s that we purchased new in 1979-80! They still sound and work great. I dont have any problems using them.

I do know I love the sound of them, its a combination of the Alnico magnet and aluminum diaphragm and phase plug that makes this driver what it is. I have neodymium magnet drivers, and for whatever reason, I dont love them.

[hapy._.face]

NEVER heard anyone say that they were not satisfied with a good working Alnico driver.

Aw, Steve. I'm not upside down smith horn- I was simply holding my end up in this mess.

With regard to your comments: Me either. I did have a conversation with a guy yesterday about how he A/B a 112A/H and he claimed the ferrite version 'meshed' better. However, the variables are so many to mention that his take is flawed. That's why I asked MJC if he had done the A/B; I wanted his opinion. But, I guess he thought I was being a smartass..

We're talking vintage drivers, so I know if I had a choice between an AlniCo driver and a ferrite (being the same model)- I'd choose the ferrite every time. Having the ferrite gives me piece of mind. It's a silly notion, but it's my silly notion.

The specs do show differences, though. I read about AlniCo5 and the care that has to be considered when handling it for speakers. I read you should never bring opposing poles together for more than a few seconds or the energy is greatly diminished. Can anyone verify this? I wonder how many pulled drivers ended up sitting close enough together to have any such effects?
I'd like to know (for the sake of knowing) what the specific details are regarding the reintroduction of AlniCo (by Harmon's perspective). I wonder what exactly has been done to ensure stability. I don't think anyone questions the values Alnico offers, so if the flaws have been addressed- what's not to love!?

[Steve Gonzales]

Right on Scotty, there are so many people that own and enjoy their Alnico drivers. We read all this information about the older drivers and I think some take it a bit too seriously. I mean, if you were enjoying some music and after a while, sat down and surfed the LHS and found out that Alnico has some drawbacks, would you then go back and not like your speakers anymore because they had Alnico magnets?. There are sixty year old models that can still put a smile on peoples faces. Technology advances, and that is good, but , there is still alot of mileage left in them, good mileage.

[Steve Gonzales]

Just think about any comparison. Unless they are absolutely equal, i.e., same run time, power level, enviromental conditions etc., no one can say they've met the burden of proof. JBL can say that because they develop them and can meet the level playing field criteria. Think of all the other contributing factors that will vary the results of the common man's tests. How are the spiders? How are the surrounds? Who did the work? I have LE14a's and LE14H's side by side. They both perform very well. the only thing that I might detect that would be a difference is that the Alnico seems warmer in the midrange. Is this because of the Alnico? I don't know. If it satisfies the owner, then that's the desired result.

[hapy._.face]

Right on Scotty, there are so many people that own and enjoy their Alnico drivers. We read all this information about the older drivers and I think some take it a bit too seriously. I mean, if you were enjoying some music and after a while, sat down and surfed the LHS and found out that Alnico has some drawbacks, would you then go back and not like your speakers anymore because they had Alnico magnets?. There are sixty year old models that can still put a smile on peoples faces. Technology advances, and that is good, but , there is still alot of mileage left in them, good mileage.

Agreed, somewhat. I think it depends on how the driver(s) were/are treated.

I will go on record here and say I have heard some d123's and d130's (used in fender amps) that ended up sounding completely different, and I suspected the AlniCo had began to fail. It is only suspicion, but the differences were all linked to speed and overall ability to produce sound at it's intended spectrum with any heft. I swapped them around, and noticed major differences. I had a twin with a pair of alnico drivers. They sounded quite equal (from what I could tell). I used one in a single driver cab for a while, and when I put it back in the twin- it was different. I put the other driver in the single and it was still very much "alive". Again, there are a lot of variables- but knowing what Alnico can do makes you suspect that- even when it could be wrong.

OTOH, I still think choice vinyl is better than CD's! In every way! Not because of specs, but it's what my ears tell me. If Alnico is putting smiles on people's faces- then go Alnico. If tin cups and shoestrings makes people happy- I say go for that, too. :)

[Steve Gonzales]

We both know that a driver that has been used in a tube guitar amplifier has lived a life of torture, LOL , and I'm sure that this is quite the proving ground for any transducer. No doubt that anything that can go wrong, will.:D

[scott fitlin]

Well, my point is that alnico drivers can last, and yes, most guitar amp speakers live a life of severe overdrive, and can partially demagnetize. But, drivers that arent seriously abused can last and work. I am one that thinks alnico drivers have a certain tone, a crispness that I like. Put another way, I have yet to find another driver I like better from the more advanced and modern school of technology. And I have a few drivers of the modern types!

However, as my preference for compression drivers leans to alnico, oddly enough, I prefer ferrite magnets for my woofers! I have found alnico woofers to be a bit too warm for my LF tastes, and has a bit too much bloom. This is just me, as others have different tastes.

[Steve Gonzales]

Well, my point is that alnico drivers can last, and yes, most guitar amp speakers live a life of severe overdrive, and can partially demagnetize. But, drivers that arent seriously abused can last and work. I am one that thinks alnico drivers have a certain tone, a crispness that I like. Put another way, I have yet to find another driver I like better from the more advanced and modern school of technology. And I have a few drivers of the modern types!

However, as my preference for compression drivers leans to alnico, oddly enough, I prefer ferrite magnets for my woofers! I have found alnico woofers to be a bit too warm for LF tastes, and has a bit too much bloom. This is just me, as others have different tastes. Exactly the same for me in every way!.

[Steve Gonzales]

One thing I feel the need to address, to put the rest of what I've said into context. It is that it takes alot of time, effort and experince to recognize a good Alnico driver from a bad one. Most of us veterans are fairly adept at this. Without a Gaussmeter, it is a crapshoot at best. I rely on a host of factors that include knowing it's history, i.e., did it spend years in a stagemonitor or some other stressful workcycle?. I have to trust the person that it is purchased from (should have said that first). Who did the work if it was rebuilt? So having said that, I'm not recommending that a novice should go out and buy older Alnico drivers because I say that they are okay. It has taken a long time to gather up a nice bunch of premium examples for myself to enjoy. Sometimes the gamble doesn't pay off. But that is true for any type of driver.

[Titanium Dome]

As Grace Slick so gloriously intoned, "I don't care if my lettuce has DDT on it, as long as it's crisp."

As for AlNiCo mags in the K2 woofer, I'm going out on a limb to say that there were a number of wonderful drivers available during the development cycle for this product, and yet JBL chose to go ahead with the 1500AL. It wasn't the only driver they had lying around so they had no choice but to use it. In fact, it wasn't lying around at all; it was developed on purpose.

Don's excellent article really lays a lot of this out for all to read.

http://www.audioheritage.org/html/projectmay/technology/1500al.htm

While it may read as hyperbole to some, Don's final sentence rings true to me:


In summary, the 1500AL sets an unprecedented standard for accuracy, dynamic response and freedom from distortion.

This is due in part to the much improved AlNiCo structure. To make comparisons to any legacy AlNiCo driver or to invoke the well-known foibles of legacy AlNiCos would be an error, IMO, because they simply do not have relevance, except for historical context. (Love history, BTW. ;) )

Every part of a $13k JBL speaker demands excellence and attention to detail, and the development and inclusion of this driver is one of many, many things done right by its designers.

[hapy._.face]

Great post, 'Dome (as usual). :)

It makes me wonder if the development of the 1500AL was influenced by marketing factors. Let's face it- most products are. The choice to implement ALNiCo could have been an indirect way of selling more K2's to the ALNiCo lovers.

ALNiCo never really went away, right? Don pointed out to me that ALNiCo has been reserved for expensive drivers the whole time. So, perhaps the 1500AL was a "cost no object" project driver- much like the whole K2!

I guess the primary values of ALNiCo would be it's speed, and agility (??). Nothing is quicker than the 1500AL in what it does.

Whatever the reasons- JBL certainly made a classic "statement" speaker that pays homage to their history and advances technology to bring the best forward. It's a beautiful thing! :D

For any of you that thought I was dissing ALNiCo- look at the "eyes" in my avatar, and follow my well documented lust/love affair with the K2. Giskard said it best when he said the 1500AL is 'ALNiCo done right!'.

[Steve Gonzales]

When Carl Lewis set the all time long jump record, I don't recall people saying: "Yeah that Bob Beamon couldn't jump". Beamon still amazed the world by setting a 29-plus foot jump that stood for a long time. I respect Don and Giskard's opinions. I interpet them as being absolutes in fact, from an engineering point of view. Given that, it still remains a fact also that the AlNiCo legacy drivers can still 'jump' and that they are still being used and enjoyed today, all over the world. That is proof enough. It's a fine line between stating that the new technology is supreme and an interpetation that is dismissing the Legacy's as viable. I'd hope to think the former is true.

[toddalin]

One thing I feel the need to address, to put the rest of what I've said into context. It is that it takes alot of time, effort and experince to recognize a good Alnico driver from a bad one. Most of us veterans are fairly adept at this. Without a Gaussmeter, it is a crapshoot at best. I rely on a host of factors that include knowing it's history, i.e., did it spend years in a stagemonitor or some other stressful workcycle?. I have to trust the person that it is purchased from (should have said that first). Who did the work if it was rebuilt? So having said that, I'm not recommending that a novice should go out and buy older Alnico drivers because I say that they are okay. It has taken a long time to gather up a nice bunch of premium examples for myself to enjoy. Sometimes the gamble doesn't pay off. But that is true for any type of driver.

No need for a gaussmeter. For $27 JBL ($25 at OCS) will simply recharge the Alnico magnets to like new condition. (I just had three 2205Cs redone as 2235's and recharged.) Do this when it's time for a refoam (~15 years) and if not abused with massive power and heat, Alnico should go on forever.

[speakerdave]

As for AlNiCo mags in the K2 woofer, I'm going out on a limb to say that there were a number of wonderful drivers available during the development cycle for this product, and yet JBL chose to go ahead with the 1500AL. It wasn't the only driver they had lying around so they had no choice but to use it. In fact, it wasn't lying around at all; it was developed on purpose.
Well, yeah, but that doesn't mean that any previous driver is borscht. If a company is going to market a new statement speaker at $30K/pair it needs to have new technology the brochures can talk up; otherwise there is no point.

The 1500AL is a very articulate woofer that extends well into the midrange, but it don't go low. For that you need something else. In other words, the usual trade-offs apply. Some people would say the Altec 15" Alnico woofers have been doing that for a long time.

My recollection of the history is that the developments in ferrite woofer motors were undertaken to get back even with Alnico for sound quality. What, exactly, was the innovation which took the ferrite motors beyond Alnico for sound quality?

The K2 S9500, M9500 and S5500 were two-ways; now the statement speaker is a three-way. None of these seem to have disproven the benefits of a 4-way as in the 4343, -44, -45. That big horn in the S9800 can match well with its 15" woofer because of a trade-off down low, as in a Valencia.

Me, I'm intrigued by Widget's four-way. It extends the work of the midbass down below 100, like the 212. It uses a larger horn and lower cutoff for the midbass. And then it puts the subwoofer in the box. A supertweeter on top to round it out. Only the subwoofer has a ferrite motor, by the way.

Onward!

David

[Steve Gonzales]

Both excellent posts. Sometimes you have to state the obvious to dispell a growing concern.:D

[4313B]

What, exactly, was the innovation which took the ferrite motors beyond Alnico for sound quality?http://audioheritage.org/vbulletin/showthread.php?t=4746

Then JBL took some of the goodies that made SFG Ferrites better than the old AlNiCo V and incorporated them into the 1500AL :D :applaud:



The old AlNiCo V motors are fine for most everyone if you recharge them before reconing them. That should be standard operating procedure. I've posted that numerous times.

[Titanium Dome]

Well, yeah, but that doesn't mean that any previous driver is borscht. (snip)

David


That's why I called them "wonderful." :yes:

[John]

Well it was so long ago, but I do remember that the L212 system at full retail was priced at $4995.00 when it first hit the show room floor at the local JBL dealer up here in Winnipeg. But I would imagine it could be had for a bit less than that.;)

[hapy._.face]

snip....'But I would imagine it could be had for a bit less than that.';)

Yessir. Especially on today's market! :)



If a company is going to market a new statement speaker at $30K/pair it needs to have new technology the brochures can talk up; otherwise there is no point.



Man, if that ain't the truth!! Sometimes they have to re-invent the wheel because people want the faster, rounder ones that are out now!

[speakerdave]

I love the technotes. I can never tell if they are advertising or what, and there is something in me that just wants to question them even though I am far from technically competent to do so--so here goes:

Symetrical field geometry: According to past illustrations, the Alnico motors already had it. According to Technote Vol 1 No 9 there was still something lacking after this was done for the ferrite motors.

Inductance modulation: This is a proposal of a solution of a problem of overhung voice coils. With underhung coils (Altec 604, JBL LE15 and 1400nd) you don't have this problem. In the 1400nd literature it was stated that during development of that woofer they found that overhung voice coils measure better but underhung sound better. Overhung voice coils maximize output for a given cost of magnet. As for this problem with overhung voice coils, and

Flux modulation: this is a wild guess, but isn't an Alnico magnet its own shorted turn?

Power compression: Not a problem at home.

Reduction in distortion from 1% to .3% at 10 watts: A challenge for most people to hear, I would guess. Again, not a problem except at volumes louder than most listeners will be using for very long. For home use, better peaks, maybe, but these figures were taken from the 128, a 12" woofer. Would the figures for a 15" woofer be the same, better, or worse? Who knows?

This technote, like others I have read, reads like advertising and is addressed to the SR and monitor market. It's relevance at home is unclear at best. It does not acknowledge, like the 1400nd literature, that there can be a disconnect between measurement and sound quality, and it does not attempt to characterize the sound of any of the woofers discussed.

Judging by the response curves given, every one of the 15" woofers discussed should be crossed over well below 1000 Hz.

[Robh3606]

Power compression: Not a problem at home.

I not so sure about that. That's one of the prime reasons larger more efficient systems sound more life like and free of strain. I think any method you use to reduce heat and it's effects in the coil is a good thing and may be more audible than we generally realize. It's just not recognized for what it is.

What you should really do is look up the referenced AES articles before you dismiss the entire content of the Tech Notes as advertising copy.

Rob:)

[Robh3606]

I think that it is less of a problem in a typical home installation.

I think depends more on your driver sensitivity and may actually be more of a problem with people using lower sensitivity drivers than our JBL's. No matter how you cut it most speakers are on the wrong end of the power curve. When you realize that you are lucky to get 1 watt out for every 100 you put in the VC temp and heating is a real issue in most designs used at home. The higher efficiency higher power handling drivers have a real advantage and when we feed them only 10 watts then yes I would agree but drop the sensitivity down 6Db and now its 40 watts. That's a lot more heat and with smaller coils and lighter magnetic structures it's got no place to go.

Rob:)

[speakerdave]

One thing to ponder- perhaps it really IS as good as they say it is (?)

Well, I certainly understand that there is a commitment to JBL in these parts, but if it is a sacred cow I'm outta here. I didn't think it was necessary to say this, but maybe it is. I think the JBL ferrite woofers are great. I own some, and will own more. And I think JBL ingeniously confronted a real glitch in their business when the cobalt supply went dry. AND I admit that I don't know a whole hell of a lot about the technology, but . . . . still, that paper does not end the conversation about ferrite and Alnico, and goddamit, it is in fact promotion masquerading as technical objectivity, and when I see that I just want to jab a stick at it.

(Also, please note, JBL Pro does not have the paper posted on their website.)

But I think that when you combine the papers on the 1400nd, the 1500Al and the fact that the 604 and the LE15 are all underhung, you could make a case that when a speaker company wants to go for sound quality, damn the cost, they make a driver that is underhung.

David

[speakerdave]

I have considered deleting the offending posts for the following reasons:

1) They're very probably wrong. I'm really not qualified to question someone else's technical information. My expertise would be in the rhetoric of the presentation, and that is probably where any inadequacies would be.

2) I feel conflicted because I think open debate is a good thing (fun, anyway, sometimes) but I am perfectly aware that idea is not harmonious with the fundamental pragmatic of these forums.

3) My posts are offensive to people whose help I've accepted in other matters.

But I've decided to leave them, since they can't be unsaid anyway.

I would like to offer my apologies to anyone whose work I've demeaned by them.

So long. See you around the barn yard.

David

[spkrman57]

Please keep them around for me. I sometimes re-read things like that to get my bearing when working on projects!

Your work is appreciated by most of us here!

Ron




They're just Tech Notes. I wouldn't worry about it. Easily deleted and restored at the click of a button. You weren't the only one who stated they seemed self serving. We try to post only the Tech Notes that aren't on the JBL Pro site. David Smith wanted one of them posted and we gratefully obliged. If everyone thinks they are self serving we can obviously delete them. I don't care one way or the other. I have them all for my personal use so I don't need them here too unless I get the urge to post a link to them. I don't necessarily have to do that either.

[hapy._.face]

snip....'2) I feel conflicted because I think open debate is a good thing (fun, anyway, sometimes) but I am perfectly aware that idea is not harmonious with the fundamental pragmatic of these forums.'

SpeakerDave,
We have something very much in common. Just remember: It wouldn't be a debate if no one disagreed with what you/I say. ;)

Giskard,
As for the 'self serving' part- even a logo is self serving. There simply is no shame in a business being self serving- IMO. I don't mind; There is great info in the technotes! Keep them up, please! It is greatly appreciated. It sure would be a shame to delete them just because people think it reads like a commercial. Let's face it: it IS a commercial! So what!? We can wade through it. Besides, Dave made his intentions clear- he just wanted clarification on the details...

'Business is in the business of staying in business!' (I can't remember who said that...)