Identify the mystery JBL woofer?!

[Dave Zan]

There's an AES 1991 convention paper by JBL staffer D. Button that compares 15" woofers.
It's a technical discussion rather than a sales pitch so the drivers aren't identified by brand or model.
One is clearly a JBL but I can't identify the model.
The specifications are identical to a 2227 frame - 600W, 4" VC, 0.5" thickness top plate, pole vents etc.
But the Xmax is much more than a 2227 and Mms is 150 gm so it looks a 2226/2227 cone with extended VC and more mass.
This doesn't match any model in the JBL Pro Thiele/Small parameter list.
But some subwoofers are not in that list, consumer ones for example.
Anyone know what this is?

David

[Earl K]

http://www.hifido.co.jp/photo/02/072/07275/c.jpghttps://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcS6hc8tnwktbwxaa_Zid6Kdiw_K6AalZ X78T-0r-P_-NUv-7Q09Mw (http://www.audioheritage.org/vbulletin/showthread.php?11347-ME150H)

:)

[Dave Zan]

:)

Thank you, that was fast.
Had a faint recollection of this but could not remember the exact model number to check.
I take it the ME150 is now unobtainable and JBL recone kits too?
So I'd need to recone a 2227.
The cone seems to be a 2226 (=2227?).
Would be nice to keep it all JBL, maybe I could use a VC from the 2242.
Since it won't be factory standard anyway, maybe keep the Mms down to close to the 2226.
That would make a driver with lower distortion and better efficiency than the 2226.
Hmm, with a little work to retune the cabinet, that looks quite doable.

Best wishes
David

[Earl K]

Guido, ( an LHF member from Germany ) has obtained these cone kits ( seemingly on a pretty regular basis ) and reconed quite a few 2227's into ME150H(s) .

( From Observation ), if one goes commando using the ( apparently ) regular Hitachi ribbed cone mated to a 2242 coil ( but leaving off the cones heavy aquaplas coating ), one will get a woofer with a rising mid-range response ( as is typical of all the "deep-gap/overhung coil" SR woofers ( from the 90's ) with their highish BL figures ) .

I saw your request at DIYaudio re: "modern transducer design books" / sorry, but I don't really know of anything available .

:)

[cooky1257]

Not got access to the paper but could this be a opportunity to plug the gaps in the tech data on this driver?

[Dave Zan]

...could this be a opportunity to...

Unfortunately the driver in the paper may not be exactly an ME150.
The paper lists the cone mass as identical to a 2226 but the Mms is 50g heavier, more than can be explained by the small increase in VC.
So it looks like a separate mass has been added whereas Earl says the extra mass in the ME150 is added as Aquaplas to the cone.
Perhaps it's an early prototype where a lumped mass was added to a standard cone for a quick test.
Or perhaps this is just a difference in interpretation and Button doesn't count Aquaplas as part of the cone.
The paper is from 1991 and the ME150 specification sheet is dated 1994.
Was ME150 production started after the paper? In that case the paper may show a prototype.
If the ME150 was already in production in 1991 than I expect that is what the paper tested.

I did wonder about this because the frequency response does not show the rise that Earl mentions as typical.
Is that due to extra Aquaplas or would any form of extra mass have a similar effect?

Best wishes
David

Earl, "Hitachi" cone? Where is that information from?

[Earl K]

The "Hitachi Cone" reference had been casually made in the forums ( by another poster ) a couple of times within the last year.

Please note my use of the qualifier, "Apparently" .

I had always assumed the 15" ribbed cone came from either Hawley Products Inc. (http://www.hawleyproducts.com/) or Mogami America Inc. (http://www.moreopp.com/company-details-5/121171743.html)

LOUDSPEAKER CONE VENDOR SURVEY 2014 (http://read.uberflip.com/i/249385-voice-coil-february-2014/13#)

:)

[1audiohack]

The "Hitachi Cone" reference had been casually made in the forums ( by another poster ) a couple of times within the last year. :)

If that was me, the source was George Augspurger. He shared with a friend and I the story of how the 2235 came to be. If that particular hard paper is/was used in other JBL cones I do not know.

If that wansn't me, sorry for the swerve, carry on.

All the best,
Barry.

[Earl K]

Thanks for weighing in Barry .

:)

[Dave Zan]

...response ( as is typical of all the ...

You have restarted my curiosity about why the response rises.
It's not really about a JBL mystery woofer anymore so I have taken it up in a thread at DIYaudio
http://www.diyaudio.com/forums/multi-way/282899-efficient-direct-radiator-woofer-optimization.html
if you're interested.

Best wishes
David