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Thread: JBL 2205J Question

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    JBL 2205J Question

    I recently acquired a pair of 2205J's in excellent condition. Searching through the library here, I found them listed in the 1980 Professional Products catalog but there is no mention of what system they were used in. Does anyone know which system(s) these were designed for?

    http://www.lansingheritage.org/html/...s/1980-pro.htm

    I also have a pair of Cabaret 4691B cabinets with 2370 horns but no drivers or x-overs. Can the 2205J's be used in them and if so, what x-overs and HF drivers would be suitable?

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    Senior Member RMC's Avatar
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    Hi bedrock,

    The 1980 is probably the last catalog where they were ever shown. They are not in the 1982 (replaced by 2225) and I think the catalog was issued every second year... I've owned a pair of the H version purchased new since early 80s, still nice condition and no plans yet to let them go...

    I don't recall ever seeing a mention of "designed for enclosure model # ...". The 2205 was launched around 1971 and then described as "15-inch Heavey Duty", naturally based on 1971 standards, not 2019.

    The 2205 was specified and used mostly in rear-loaded folded horns cabinets # 4520 and 4530 with short-throw for discos for example. See the 1971 Pro catalog in the library. They can still be used in vented box. So these were made for about 10 years.

    As for the 4691B, it uses the E-140 Musical instrument driver with extended response (bass guitar). On the other hand, the 2205 and E-140 are close cousins, with the former optimized for music reproduction in sound reinforcement and the latter for music production. Their T/S parameters regarding woofer/box combination are sufficiently close that they are both interchangeable low-frequency wise. So the 2205 would probably acoustically fit in the 4691B (4.5 cu.ft.), depending on tuning frequency used.

    However, the 4691B has a high-pass network at 1.5 khz because the E-140 can go higher being a musical Inst. driver, whereas the 2205 highest recommended crossover is 800 hz. The compression driver used in the 4691B is the 2425J and i'm pretty sure the woofer was 8 ohm.

    Using the 2205 with a 2425 at 800 hz isn't a problem since the mid/high driver is recommended for crossover as low as 800 hz (12 db/oct). The 4691B was a two-way system. Regards,

    Richard

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    Hi Richard,

    Thanks for the very informative reply. That's good news that the 2205J's can be used in the 4691B enclosures. I also have a pair of 2425J drivers in storage so I just need to find some crossovers. Digging through the library here, it looks like the 3110 may be the way to go.

    http://www.lansingheritage.org/image...pro/page17.jpg

    Now I need to make room for these monsters...

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    Hi Richard,

    as the first 2205's featured AlNiCo motors, were they also related to the K140?

    Best regards!

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    Hi bedrock,

    If you look at the 4691B Tech Manual attached you will note the low-frequency range given is 40 hz at - 10 db. This is realistic and the 2205 should do about the same. That means this is NOT a subwoofer box and don't expect nor try to get very high level subwoofer type performance from that enclosure otherwise you will bust the woofers. The sheet does call the system "High-level playback/reinforcement", NOT high-level sub bass...

    Sorry for the poor printing on that sheet but that's how it came from JBL's data archive.

    The system's sensitivity number looks impressive but for MI drivers like the E-140, with their rising response, its measured at 500-2500 hz leading to higher number. whereas its usually done at 100-500 hz for woofers like the 2205 (97 db). If both drivers were measured at 50 hz they would probably reach 93 db or so. There's a lot of marketing involved in sensitivity numbers simply because SPL is the name of the game, specially for MI enclosures...

    The 3110 or similar crossover does look like the way to go for your project, unless you decide to go active xo.

    Regards,

    Richard

    JBL 4691B Tech Manual[1].pdf

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    Hi Kay,

    I'd say the 2205 and K-140 are probably more like brothers (not twins though), as they are even more closely related than the E-140/2205. The parameters mentioned in the JBL T/S table are the exact same for both 2205 and K-140!, except for Xmax. The K-140 98 db sensitivity was also measured 500-2500 hz, like E-140.

    Considering the above, for the purpose of LF box modeling, the 2205 and K-140 are quite interchangeable, and having the same baffle cutout makes them like drop-in replacement for each other (for LF part only).

    Naturally, above low-frequencies their routes differ, one being optimized for SR, the other for MI with its usual rising response, as well as some distortion sometimes sought in these type, as mentioned separately by John Eargle and Drew Daniels. So these drivers are still engineered for different sound.

    Things changed somewhat with the introduction of the E-140. Not only a change of magnet material from Alnico to Ferrite. If you compare T/S for K-140 and E-140 you'll see a number of differences. For example, to boost sensitivity motor strenght was increased and cone mass reduced on the E-140. Globally, sort of a gain a little here and lose a little there re-balancing act, with main objective seemingly to increase sensitivity number.

    However, the three basic parameters for LF box modeling (Fs, Qts and Vas) haven't changed enough to worry much, in most cases, about same box suitability before and after the conversion to Ferrite.

    In the case of bedrock's 4691B, I see the little higher Qts of the 2205 VS the stock E-140 as a tiny improvement for that 4.5 cu.ft box, certainly not a loss in my view. Regards,

    Richard

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    Quote Originally Posted by RMC View Post
    The 3110 or similar crossover does look like the way to go for your project, unless you decide to go active xo.
    Thanks again for the informative reply.

    The 3110's are going for a couple hundred per pair. I wouldn't mind spending that for some in good shape but that's not always the case. Do you have a recommendation for an active crossover in a similar price range?

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    Hi bedrock,

    Since price matters, and that's ok considering not all of us here have deep pockets, then I'd say the deal of the moment (price/performance ratio) is probably the DBX 223S, on sale right now on dbxpro.com web site for $159. instead of $229. Seems like a good entry level deal to me. Plus these carry a two year warranty so you should have peace of mind for at least two years...

    I don't own it, as I use other more expensive ones, but I just looked around quickly to help you find an acceptable one at a decent price and this one should do the job correctly. The on board 40 hz low cut filter is also a good idea with the 2205 woofer. Regards,

    Richard

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    That's great, thank you.

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    If I go the active crossover route, I would prefer to mount the crossovers in each speaker. I'm going to do a search for mono crossovers, any suggestions would be helpful as well.

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    Senior Member RMC's Avatar
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    Hi bedrock,

    RE: "If I go the active crossover route, I would prefer to mount the crossovers in each speaker"
    Well, active crossovers are usually mounted in a rack, as I do, or on top of something (e.g. preamp, table or shelf), not in speakers.

    I'm not familiar with an active crossover going inside a speaker. Can't help you with this one. Moreover, going for two mono units may go above your limited budget, compared to the DBX stereo unit... Regards,

    Richard

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