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Paul Joppa
06-19-2003, 03:07 PM
A friend picked up a pair of these, in pretty good condition (he says). A curiosity that I'd never heard of before! It seems to be a 15" woofer with an LE-5 glued to the pole piece, but I can't make out the picture very well. Haven't seen them myself yet.

The brochure is available:

http://www.jblpro.com/pub/obsolete/2150.pdf

Apparently his are without any crossover. The proper crossover seems to be the 3125, also available at

http://www.jblproservice.com/pdf/Network%20Schematics/3125%20Network.pdf

which seems to be a simplified 3120.

Anyhow, does anyone recognize these? Or know anything about them? I'm especially curious about how such a beast came about, and how long it lasted.

Fangio
11-09-2006, 07:47 PM
...Anyhow, does anyone recognize these? Or know anything about them? I'm especially curious about how such a beast came about, and how long it lasted.

Would like to repeat the question - maybe someone likes to shed some more light over this one, this time - or even tell us the full story behind?

Thanks.

speakerdave
11-10-2006, 08:36 AM
That speaker is designed for sound distribution, which is to say, vocal announcements and Muzak. It is basically a two-way fullrange that covers the frequency range for speech (60-8500Hz) well on and off axis but falls off above and below that. Its usefulness for hi fi would have to be explored. It is described as "controlled excursion" which I take to mean it has a fairly stiff suspension so it can be mounted in a ceiling without an enclosure and will maintain well into the midrange and will not be wiped out by an accident with a microphone. You will not get much bass out of it no matter what you do and will want a super tweeter. Here is the URL for a data sheet on it at JBL Pro.
http://www.jblpro.com/pub/obsolete/2150.pdf

David

Fangio
11-11-2006, 02:01 PM
Thank you David, for the warning. Thought first I might have overlooked a transducer so far that's comparable to Altecs vintage coax systems.


That speaker is designed for sound distribution, which is to say, vocal announcements and Muzak. It is basically a two-way fullrange that covers the frequency range for speech (60-8500Hz) well on and off axis but falls off above and below that. Its usefulness for hi fi would have to be explored.

Where these pics come (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180047539051&ru=http%3A%2F%2Fsearch.ebay.com%3A80%2Fsearch%2Fse arch.dll%3Ffrom%3DR40%26satitle%3D180047539051%26f vi%3D1) from, such facts are commonly not mentioned. Nevertheless they've hit 300$ already.

speakerdave
11-11-2006, 02:26 PM
Nevertheless they've hit 300$ already.

I'm not surprised. With a subwoofer at 80 or 100 Hz and a supertweeter you might still get the coherent imaging which is the key benefit of the coaxial, and the woofer to cone treble blending of the 2150 might well be better than that of the 604, which is highly compromised with a woofer that is extended too far into the midrange and a horn that is partially unloaded at the crossover frequency.

And, the 2150 is Alnico, and there's always interest in that. I'm curious about the magnet structure for the small cone, though.

I just meant to say it would need to be explored, not that it was a non-starter.

David

Steve Schell
11-15-2006, 09:59 AM
The 2150 was used as a ceiling speaker in high quality distributed sound systems. A local audio reseller was offering used pairs of them for $150 some years ago; these had come out of conference rooms at the Long Beach Convention Center. I didn't buy any, but a friend bought a pair. A few months ago I noticed what looked like 2150s installed in the ceilings of the gate areas at the Philadelphia airport. They sounded good.

chuckb
01-30-2015, 03:25 PM
Paul...there's a guy in Oklahoma who designed a 14 cu' (?!) ported enclosure for JBL 2150s that is tuned for 34 Hz. He likes the transients the 2150's stiff cone suspension offers, and I like the imaging one gets from the centrally located LE5-2 in the 15" D130 basket. I'm presently listening to a pair of 2150s in 6.4 cu' ported utility enclosures. Although I read LE5-2s extend out to 15 kHz, I'm currently using them for the mids and added a pair of 175 drivers with 1200 kHz horns and L94 lenses for the highs. These speakers have great detail and require very little power to make a lot of sound. But the bass is too boomy...mid/upper bass?...for my tastes. I have a single 2150 that is looking for a home, and awhile back I came across two more NOS 2150s that are still in their JBL shipping boxes. Norm (the guy from OK) kindly sent me drawings for his refrigerator size enclosure. I'm going to build one as a test. If the 2150 sounds as good in it is I hope it does, I'll build 2 more, one for the other main front and one, laid on its side, as the center channel. I'm thinking about building 2 dipole enclosures for the 2 other speakers that will result in an all-2150 surround system. I've heard that ideally, a surround system should have the same speakers all the way around. I think that may apply more to 5.1 music (SACD, DVD Audio, Blu-ray Audio) than 5.1 movies. We'll see how this works. If this sounds interesting, google jbl 2150 B39(big black box version 9). Norm goes into more detail in his article.

2150s have good pedigrees, an LE5-2 in a D130 frame, 4" edge wound copper ribbon voice coil, and massive Alnico V magnet structure. But as another contributor in this forum correctly stated, the 2150 was designed for distributed sound systems in which they would typically be ceiling mounted. JBL gave the 2150 a stiff suspension to prevent the cones from sagging when ceiling mounted. This improves transients, a good thing. But it also results in attenuated lows, a bad thing. RF is 55 Hz. That's where Norm's 34 Hz, 14 cu', enclosure comes in.

The only problem I have is that I don't know where I'll put these things if I build them. But if I applied common sense to my hobby, I'd have to change hobbies.

speakerdave
01-30-2015, 03:58 PM
Hi,

The original post was made 11 years ago, the last entry about eight. You're welcome to revive the thread, but the dates suggest that the previous participants may not notice.

As to your proposed project, yes 14 cu ft is awfully large and really heavy, the one advantage of that being that your spouse probably could not move it out alone. And I would think the outrider midrange/tweeter would definitely diffuse the imaging. It might be worthwhile to experiment with rear/upward facing supertweeter(s) to add air and a sense of spaciousness as Heraga has done

The coaxial format can work really well as a point source, but it is not necessary for good imaging, which can be obtained in other ways, such as, for example, a two way woofer/horn treble crossed in the mid to upper hundreds.

chuckb
02-25-2015, 06:23 PM
Speakerdave,

Thanks for your comments. I especially appreciate your thoughts about tweeter placement. For the single 'prototype' I plan on mounting the 175/horn/lens ass'y inside the cabinet, directly above the 2150. Norm put his 375 and horn on top of the cabinet. I'm a believer in speakers being heard, not seen (so I'm going to build a 14 cu' enclosure!), and I don't want a raw driver in plain view. Perhaps its close proximity to the 2150 when locating it inside the cab will help the imaging. I'm a bit hesitant to mount it up and in back and letting the highs reflect off the walls and ceiling. But it wouldn't be difficult to try that out by jury rigging something after the build. The same goes for building dipole enclosures for the 2150 surrounds. Dipoles, by their nature, diffuse the source. It shouldn't be difficult to build a test dipole panel. So we'll see. I agree with your comments on a 2-way with the crossover point somewhere in the mids. I prefer 2-way speakers to-3 ways.

I was outside in my speaker room with a tape measure and Norm's drawings. I have room for them. But I also have pairs of L100Ts, 4425s, 120tis, L20Ts, 4612s, 4411s, LE14As with LE5-2s and LE20s in homebuilt cabs, and a pair of 2150s in utility cabinets in the same room. The 2150s will go in the big cabs, but something else...many something elses?...will have to go. But how do you decide which of your kids you'll box up and put in the garage? The house already has a pair of L150As, a 4412 center channel, and 4410As for the rears in one room, and pairs of 4406s and Control 1s in another room. A problem of luxury, for sure.

The first time my wife saw the surround system in the living room, she left for the kitchen. But I turned down the lights, asked her to join me, and put on James Guthrie's 5.1 Blu-ray mix of Wish You Were Here, after which she replied it didn't look that bad after all. Needless to say, I have an amazingly understanding wife!

I've repeated this before, and I'll repeat it again...A lot of audio gear is good. More audio gear is better. Too much audio gear is just right! (Stolen from this forum.)

Thanks again for your input.