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boputnam
04-22-2003, 09:18 PM
Notwithstanding that 12-inch transducers have as many proponents as opponents, I'm looking for some experience here.

1) Why no LE12?

2) What are the specs of each the 123A-1 (alnico, positive) and 2213H (ferrite, negative) - and why were the manufactured at around the same time for nearly identical applications?

3) Is the 2202 the flattest response 12-inch transducer JBL made?

4) other thoughts/comments?

Thanks.

4313B
04-22-2003, 09:29 PM
"1) Why no LE12?"

Because JBL twelves suck and there was no way they were going to label any of them "Linear Efficiency".

JK! The LE12C was a composite transducer consisting of the D123/123A basket and the LE20 HF.

http://www.lansingheritage.org/html/jbl/catalogs/1976-comp.htm


"2) What are the specs of each the 123A-1 (alnico, positive) and 2213H (ferrite, negative) - and why were the manufactured at around the same time for nearly identical applications?"

One is for Pro and one is for Home.

The TS parameters are here

http://www.jblproservice.com/pdf/Small%20Thiele%20Parameters/Thiele.pdf

"3) Is the 2202 the flattest response 12-inch transducer JBL made?"

Oh no. That distinction would quite likely go to the 128H/128H-1.

Robh3606
04-22-2003, 09:59 PM
The 123-a was the original alnico the 2213h was a ferrite replacement when they changed over.

I have used 123A, 122A and 128h-1. The 128h-1 is really a nice smooth sounding woofer. I like the 122a's too but don't use them above 300hz.

Hey Giskard you wouldn't have T/S on the 129H??? JBL came up short for help.

Thanks

4313B
04-22-2003, 10:32 PM
"Hey Giskard you wouldn't have T/S on the 129H?"

Nope :(
Sorry

boputnam
04-23-2003, 09:28 AM
Thanks, Giskard and Robh.

I knew about the LE12C but don't favor composite transducers. Maybe I'm wrong there...?

It's really odd that the 123-A at the time it came out was positive - most else then was negative. It must have been a confusing time aroung the water cooler at LBJ... Whoops - JBL.

"Negative is Good"

boputnam
04-23-2003, 09:52 AM
The Thiele specs on the 123-A and 2213H are virtually identical (I've looked at this before, equally mystified on distinction). The only significant variance I can see is the Pe - with the 2213H having higher peak power handling.

Am I overlooking something, or is there a notable difference in their response curves? Is the 123-A noticeably "better" at all?

Sorry to beat this to death...

Robh3606
04-24-2003, 04:44 PM
"The Thiele specs on the 123-A and 2213H are virtually identical"

They are supposed to be the H was the ferrite replacement when Alnico was no longer available.

Rob :)

boputnam
04-24-2003, 06:53 PM
I wondered that, thanks.

So, give me the brief "brief" on the alnico-ferrite argument (which goes on endlessly, I know). Was ferrite phased in because of the demagetization alnico suffered, or is that too another "myth".

And, having both on the bench, which would you choose?

Robh3606
04-24-2003, 08:52 PM
OK

There was a war in Africa so Cobalt was no longer commercially available which is a major component in the Aluminum Nickel Cobalt/ Alnico magnets. So they had no choice but to convert to ferrite.

Which one to choose??? I use both and they work great at home. If I was a pro I would go Ferrite because of the demag and power compression issues with alnico.

Rob:)

boputnam
04-24-2003, 09:22 PM
If true (I trust it is, but wow..), it makes more than perfect sense.

I'm an economic geologist (metals), and Zaire (now Democratic Republic of Congo) seemingly is god's joke - place enormous mineral riches (diamonds, copper, cobalt, gold and zinc) of unmatched quality and in concentrations nowhere else found on the planet, and serially inhabit the region with genocidal tribes that use the wealth as weapons - to fund their terrorist campaigns. This led to the recent efforts by DeBeers to laser-label their South African, Australian and Canadian stones to distinguish them from blood diamonds from DRC and Sierra Leone.

Cobalt has limited economic concentrations outside Russia, and Australia. The deposits in Washington and Idaho states (NJ too...) are sub-grade and cannot be sensibly developed.

As with the beautiful blue, cobalt glass, so went AlNiCo magets...

Thanks very much for the history, and opinions.

Still learning,

Mr. Widget
04-25-2003, 12:06 AM
The war bit is true. At first as the supplies of cobalt started to become scarce all alnico speaker's prices went up, then the various manufacturers that were still using alnico realized they couldn't continue increasing prices endlessly so they began redesigning the driver magnet assemblies.

On some speakers I feel there is no difference between the alnico and ferrite versions. On others however there are sonic differences. The differences can be both in type and amount of distortion as well as frequency response. One of the considerations is that before JBL changed it's woofer magnet assemblies from alnico to ferrite they had quite a few distinctly different variations. For economic reasons with the early ferrite models there were many compromises made to reduce the number of necessary variations. For this reason I am not as fond of the very first round of ferrites as with the later models. I feel that the first round introduced in 1980 when all of the previous models 2231A, 2215A/B etc. were reintroduced as 2231H, 2215H the designs were not as developed as the later models with their subsequent improvements. I feel that JBL learned their lesson on the woofers and so when they finally realized that they would have to switch out the compression drivers they completely redesigned all of them except the ring radiators. All of the new drivers had completely new designations and were ground up new designs.

For the most part though the alnico issue is more lore than fact.

boputnam
04-25-2003, 07:40 AM
Thanks, Mr. Widget (you too, Robh). Filled a gaping area of my knowledge of JBL lore.

Still learning,

4313B
06-03-2003, 08:32 AM
"Hey Giskard you wouldn't have T/S on the 129H?"

Same T/S parameters as for the 122A :)

Robh3606
06-03-2003, 07:17 PM
Thanks Rob

I was wondring about that. The L65C is the only place I have ever seen the 129H??? It has to have been used in more places than the Jubal. It shows up in the Pro driver list???? It looks exactly like a 122a, cone the same diameter and lasaplas on the back on the cone, same frame. The 128H-1 is a smaller coned driver in the same frame. The one I have has a name plate and serial number. They ever sell them as a components?? Same label as the 1979 component catalog drivers.

Rob:)

Tom Loizeaux
06-07-2003, 09:47 AM
I think one of the reasons the JBL 12s aren't that popular is that the 15" versions have so much more thump to them. When you've heard a 2235 growl at 35Hz it's hard to be satisfied with a 2213. I added a JBL PB12 subwoofer to my pair of 4312As and the low end is now very respectable!
I always wondered why JBL didn't put out a speaker like the 4312 with dual 2213s in it and make it a tower design.
I think low end would be improved, SPL ability increased and distortion noticably decreased.

Tom

4313B
06-07-2003, 11:20 AM
"The L65C is the only place I have ever seen the 129H"
"It has to have been used in more places than the Jubal"

As far as I know, it was a one shot wonder. I thought it was used in a ferrite version of the L166 too but I guess I was wrong. I saw one pair of L166's with 129H's but they must have been retrofited by their owner at some point.

"They ever sell them as a components?? Same label as the 1979 component catalog drivers."

They were available as raw drivers but were never on any LCS price list that I know of.

MJC
06-08-2003, 02:08 PM
I added a JBL PB12 subwoofer to my pair of 4312As and the low end is now very respectable!

Tom [/B]

I've also added a PB12 to my HT it does have a good low end. And a good price via the net didn't hurt either.

speakerdave
07-02-2003, 03:12 PM
Maybe the reason is that it doesn't make sense economically. The only reason for using a 12" instead of a 15" of the same type is if you are willing to sacrifice the SPLs and want response down to a lower cut-off frequency in the same size box or want to use a smaller box. Once you add a second 12" the cone area increases to the point you might as well use a 15". It's cheaper.

This reminds me of another point (tangential to the thread topic). I've noticed that in manufactured speakers woofers are very often used in boxes which are smaller than optimum for flat, tight response with that driver. It's certainly true of my L65a's. Any thoughts on why?

speakerdave

Phillips SA1000 SACD player
McIntosh 2200
JBL L65a

4313B
07-02-2003, 04:01 PM
Yeah, because at one point in time that type of bass response was popular. Mostly for rock music as opposed to classical. I don't think you will find too many people who will argue with the notion that the L65A is a "rock and roll" loudspeaker as opposed to a "classical music" loudspeaker.

Marketing has some input to loudspeaker design and configuration. They might find it is easier to sell a 12" than a 10" for instance. They may decide that a certain 14" subwoofer looks too big in the optimum size enclosure and ask that it be trimed down a bit.

MJC
07-04-2003, 03:24 AM
[QUOTE]Originally posted by speakerdave
Once you add a second 12" the cone area increases to the point you might as well use a 15". It's cheaper.


Well, you get a better overall bass output by using two subs. Standing waves are formed along each room axis (ceiling/floor, front/back wall, left/right wall). Placing a sub at the mid point of the sidewall and another at the mid point of the front or back wall where the nulls are for the first resonance of those distances (the length and width of room) smooths out the bass response.
Putting a single sub in a corner will amplify the first resonant bass frequency of the length of the room. This resonance will be much louder than the rest of the bass spectrum, making the overall bass sound boomy and unnatural.
For more on this subject see the "Home Theater Architect" in the latest Stereophile Guide to HT (July/Aug. 2003).

Earl K
10-06-2004, 07:11 AM
Originally posted by boputnam
Notwithstanding that 12-inch transducers have as many proponents as opponents, I'm looking for some experience here.

1) Why no LE12?
2),,,,,,
3),,,,,,
4),,,,,,

Thanks.

Well Bo, now we know that there is a LE120H-1...

Used in Europe in the L90 and in the L7 in the North America . At this time, little info is available about this transducer except that it is available from Harman for @ $ 193.00 . Here's todays' pricing for posterity . At that price ( unless it's actually junk ) why buy old JBL 12" woofs from eBay?

< Earl K

jblnut
10-06-2004, 12:19 PM
Why ebay ? Because you get the thrill of paying more for something that you otherwise would have, plus the excitement of waiting a week for it to arrive only to find out that the shipper put it into a tissue box with no packing material.

Ahhh..I love a bargain :-)


jblnut

boputnam
10-06-2004, 12:52 PM
Originally posted by Earl K
Well Bo, now we know that there is a LE120H-1... Good sleuthing, Earl! :thmbsup:

Earl K
10-06-2004, 01:09 PM
Originally posted by jblnut
Why ebay ? Because you get the thrill of paying more for something that you otherwise would have, plus the excitement of waiting a week for it to arrive only to find out that the shipper put it into a tissue box with no packing material.

Ahhh..I love a bargain :-)

Yep, So do I :D and plus I love irony or it's mate sarcasm ;)

<> EarlK:)

Earl K
10-06-2004, 01:16 PM
Originally posted by boputnam
Good sleuthing, Earl! :thmbsup:


:cheers:
Can I put you down for 4 ?
You know,,, to make that MTM box you've been planning since last summer (2003) ? :D
Horns ? ( maybe from Widget(s)' secret stash of 1" Smith Horns ;) )

You've got some 1500sub(s) don't you ? That would be a killer setup.

<> Earl K:)

boputnam
10-06-2004, 01:19 PM
Dood! You been wandering around my shop!!?? :rotfl:

Mr. Widget
10-06-2004, 02:13 PM
Originally posted by Earl K

You know,,, to make that MTM box you've been planning since last summer (2003) ? :D



Hmmm.....

I know nothing about these twelves. Tell me more.

Widget

Earl K
10-06-2004, 02:30 PM
Originally posted by Mr. Widget
Hmmm.....

I know nothing about these twelves. Tell me more.

Widget

Ahhh ,,,,,

Well, ( I'm hoping )

More will be revealed within a few days .

<. Earl K

boputnam
10-06-2004, 02:35 PM
Originally posted by Mr. Widget
Tell me more. Yea, some interesting developments on this thread, just next door: http://audioheritage.csdco.com/vbulletin/showthread.php?s=&postid=30710#post30710

4313B
10-06-2004, 02:42 PM
The LE120H-1 was used in the L7 loudspeaker system and the LE120H-1S was used in the S3S and Citation 5.4 subs. Both use the C8R120H-1 recone kit.

The Synthesis Three system should be up on Harman's website.