Advice Needed!

[tractrix]

Originally posted by jsperber
Sorry to ask a "bookshelf" question if its not appropriate!

I actually would love to go big, but I live in a NYC apt and would like to use the JBLs in our bedroom. My living room Tannoys are huge- I can't part with them as my Dad bought the original Chatsworth cabinets new in the late '50s- and they sound fantastic!

Besides ebay, can anyone recommend other sources for drivers or whole speakers?

Best, Jeff

www.jamminjersey.com the best place to find your used altec and jbl really ebay a joke check out jammin jersey

[Triumph Don]

Hi Jeff! I just completed a father/son project bedroom set. Got a pair or Radience series 103 [10",5", 1.5"] 3 ways at a barn sale. Junk componets, very nice cabinents, similar to L 100's but 1.1 cu.ft. larger. After lots of Forum advice we found some LE 10's, sent them to Robb in FLA for refoam. Next were mint LE5 mids [out there with patience!] and LE25 tweeters, all with the Alnico mags. Some scrubbing, sealing, polishing, new insulation, NO crossover mods, they look and sound Great! For whatever reasons, much better than the 100's I still have. Total cost $335 without the fun factor! Let us know what you come up with.

[4313B]

Cool! Can we see some pictures?

[boputnam]

Originally posted by Triumph Don
For whatever reasons, much better than the 100's I still have.

Part of that likely relates to the LE10's - JBL knew something about 10-inch LF's of that vintage that took time to translate up to the 12's. The 123A's, to me, can't touch the capability of the LE10. Period.

[GordonW]

Well, you gotta compare both woofers in their RIGHT ENCLOSURE VOLUMES. For an LE10, that's about 1.5 to 2 cubic feet... but if you run the parameters of a 123A, it's about 5-10 cubic feet! That woofer in an L100, it's a testament to a well-engineered driver, that it manages to work AT ALL, in 2 cubic feet!

Have any of you actually heard a 123A in an appropriate box? I'm going to, soon- 6 cubic feet, with a passive radiator... ie, the S-70 Alpha. I think that should lay to rest, whether the 123A can cut the mustard. With a projected bottom-end extension down to like, 26 Hz (!), and a FLAT passband, it should be interesting!!

Regards,
Gordon.

[boputnam]

Well, I've no clue who you're yelling at, Gordon, with all those "!" Sorry to interrupt your rant... Let us know what you find in your tests.

[4313B]

Originally posted by GordonW
Have any of you actually heard a 123A in an appropriate box?

No. I usually reserve that kind of volume requirement for a JBL 15-inch transducer. Your experiment should be interesting though. I'm anxious to see what your final tuning ends up being. You're using the high compliance PR300's right?

[GordonW]

Giskard- Right, I've got PR300s instead of PR12s. Should be a little "smoother" on the ultimate rolloff slope with those, according to my modelling. Higher compliance PRs generally seem to work better, IME...

My guess, from my initial modeling, is that the PR is going to wind up being tuned somewhere in the 12Hz range, which will correspond roughly, to a box tuning in the 20-23 Hz range, AFAIK. When I reconed the PR300s, I used a MDF disk with a 1/4"-20 bolt sticking out the back... so I have the option of easily adding 1/4" fender washers to tune the sucker to wherever it needs to go...

Bo, really, it wasn't supposed to be anything personal. It's just that I've seen so many people write off the 123A, because of experiences they've had with it in L100s and such... ie, never giving the driver a "fair chance". Having had them apart, they're really a pretty well-engineered driver... curvilinear cone, so they have flat mids, a long-excursion voice coil, so they should be capable of good strong VLF output, and the normal built like a brick-you-know-what-house JBL basket/magnet assembly. It's a shame that so many of them are tuned "awkwardly", in L100s, 4311s and such. In a box with a PR (which will control cone motion better than a port), they could be very impressive...

Regards,
Gordon.

[4313B]

Originally posted by GordonW
It's a shame that so many of them are tuned "awkwardly", in L100s, 4311s and such.

They are tuned for abuse. They can take the juice in that particular configuration.

[GordonW]

Originally posted by Giskard
They are tuned for abuse. They can take the juice in that particular configuration.

That's DEFINITELY true. For all the hell people put L100s through, you don't see very many blown-up 123As...

Regards,
Gordon.

[boputnam]

Originally posted by GordonW
For all the hell people

I guess that is me...