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Thread: JBL 2235 with 2450SL and 2332 horn?

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  1. #1
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    JBL 2235 with 2450SL and 2332 horn?

    I'm wondering if the 2234 or 2235 woofer would be a good match, in a compact (5 cu. ft.) two-way system, for the 2450SL compression driver and 2332 horn?

    I had originally thought to find some 1400nd or 1401nd drivers, a la DMS-1, but haven't come across anything but recone kits.

    Just concerned that crossing over the 2235 at 1 kHzthe crossover frequency used in the DMS-1is asking a bass driver to play too much into the lower mid-range. . .

    Would appreciate any tips or advice on this matter. . .

  2. #2
    Senior Member grumpy's Avatar
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    4430/5 series achieves this fairly well.

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    Quote Originally Posted by grumpy View Post
    4430/5 series achieves this fairly well.
    Good to know! Thanks for pointing that out. Shall forge ahead. . .

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    Hi,

    You should be fine with a 4" (2447, 2450SL, 2451, 2452 or 2453) 1,5" driver with SL diaphragms. No real need for UHF with those diaphragms just some tweaking in the DSP. The 243* drivers do not seem to work equally good on the M2 WG

    However, M2 is a system with the specific BSS DSP, the JBL settings, the cabinet and the specific drivers. If you alter any of this it is no longer an M2 system and the result will be different.

    You may very well like the new system and be very happy with it, but an M2 it is not.

    I have tried many drivers on the M2 waveguide (I got my first pair of M2 WGs in early 2015) and my preference is the 24XX-sl drivers on a stand-alone basis. The Be drivers may sound a little closer but the early drop off in frequency and IMHO need for UHF support makes the SL a better choice. However, if you add the JBL M2 factory settings D2 is a better/easier choice unless you spend a lot of time on measuring and testing.

    Us mere mortals cannot expect to achieve the same level of system quality as achieved by JBL with thousands of hours work going into the M2 system.

    If you have the 4 drivers go with them but expect to put in many measuring hours to get them working. If you need to buy drivers get the D2s and be done with it.

    Having said all that, I build a pair 2-ways with with LE1400H woofers, M2 WGs with 2450SL cores (476Nd diaphragms), BSS DSP with tweaked JBL M2 settings and they sound wonderful.

    Im also building a system with 2451Be (Truextent) on M2 WGs and as Iveca said due to them falling off early Im going to use 045 UHF drivers with them. They will definitely not be M2 clones but have a potential to sound pretty decent.

    You choose, easy way with predictable very good outcome = build faithful M2 clones with BSS DSP. Or go you own way and expect quite some man hours and with the possibility to get very good result.

    Kind regards
    //Rob



    Hi,

    If you want to cross over that high the 2235 may not be the first choice (2332-2334 should not be used below 1khz) . I budget permits look at the new 2216 driver. If not see if you can find a L14H-2 or 3, they would do a better job at it. DMS1 was dual LE1400Nds.

    There are several other JBL woofers that would be good choices. And many very experienced people here can surely come with suggestions.

    2235 is a dedicated woofer with a heavy cone and as such would benefit from XO lower than 1KhZ. I built a monitor years ago and used a 2118 8 from 350Hz.

    If you do decide to go the 2235 route I would recommend to remove the weight ring under the dust cover to turn it into a 2234 that works better for mid.

    And while Im at it you may want to look at a newer horn/waveguide. The 2332 was a good horn back when but today the technology has moved on to waveguides and the difference is rather big. The horn sound is gone and it sound more like a big dome but with the clarity and dynamics retained. However, many prefer the vintage sound and I have great respect for that so only you and your ears can decide.

    If an option for you, I would suggest to take a look at the VTX F12/F15 (STX825) waveguide. Looks el-cheapo plastic but is in reality very good and really out-guns all of the older designs except maybe M2 for HiFi use IMHO. It also measures very good.

    There is lots written here on LH in other threads.

    Kind regards
    //Rob
    The solution to the problem changes the problem.
    -And always remember that all of your equipment was made by the lowest bidder

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    Thank you, gentlemen, for the additional comments and information. As it happens, I do have a pair of the STX825 horns. I got them for the D2430K drivers I sourced a couple of years back. Unfortunately, in tests I had done by an experienced speaker designer, they had less HF output than any compression driver I've ever heard. Given all the press and positive discussion about the D2430K, I remain completely baffled by this. Took them to a JBL Service Centre here and the guy told me they were working fine. More bafflement, but for now they're resting quietly in a box in the closet.

    I suppose I could mount the 2450SLs on those little plastic STX825 horns if I built some sort of cradle inside the cabinet to take the weight of the driver. And I do have the option of reconing my 2225 drivers with 2235 cone kits and leaving out the mass rings. I also have the option of using TAD TL-1601b instead of 2234/2235s. But not in a position right now to acquire 2216 or other woofers.... Or maybe best to postpone the project until I can afford more suitable woofers such as the 2216. . . Then there's the crossover, but that's a whole other story. I'll probably use my old DriveRack 4820 at least to get things going. . .

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    Quote Originally Posted by dubkarma View Post
    Thank you, gentlemen, for the additional comments and information. As it happens, I do have a pair of the STX825 horns. I got them for the D2430K drivers I sourced a couple of years back. Unfortunately, in tests I had done by an experienced speaker designer, they had less HF output than any compression driver I've ever heard. Given all the press and positive discussion about the D2430K, I remain completely baffled by this. Took them to a JBL Service Centre here and the guy told me they were working fine. More bafflement, but for now they're resting quietly in a box in the closet.

    I suppose I could mount the 2450SLs on those little plastic STX825 horns if I built some sort of cradle inside the cabinet to take the weight of the driver. And I do have the option of reconing my 2225 drivers with 2235 cone kits and leaving out the mass rings. I also have the option of using TAD TL-1601b instead of 2234/2235s. But not in a position right now to acquire 2216 or other woofers.... Or maybe best to postpone the project until I can afford more suitable woofers such as the 2216. . . Then there's the crossover, but that's a whole other story. I'll probably use my old DriveRack 4820 at least to get things going. . .
    If you bought those D2430K(s) used ( via eBay for instance ), the explanation of their poor performance might be more easily explained.

    You wouldn't be the first to be burned this way.


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    Senior Member 1audiohack's Avatar
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    Slots

    Hello Richard;

    Esthetically I like slots.

    In air flow round is king and a slot with a high aspect ratio is the poorest choice.

    Over a decade ago I did a ton of modeling in LinearX Encloseure Shop and found that if you stick to what I found is a thumb rule (at least for me) that is driver Sd times Xmax for port area, depending on aspect ratio and port location you can move things around several Hz is about all. I did a six box experiment on very different port placments and shapes to verify the models were correct and called it good.

    On slots I err just a tic big on area since they dont flow as well but have yet to hear them. I should do a port compression test on round vz slot sometime.

    As far as front or rear it seems like nearly all of JBLs speakers designed for domestic use have the ports on the rear to minimize midband radiation I assume. Virtually all the pro boxes including real (large format) studio monitors are ported out the front.

    All the best.
    Barry.
    If we knew what the hell we were doing, we wouldn't call it research would we.

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    In regards to the dual woofers... Have you considered trying them on their sides a la the 4350 and your TAD monitors? Maybe there is something to horizontal vs vertical configuration. Then both woofers are equidistant from the floor. May get too much reinforcement from that, but maybe the ticket.

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    Have you compared your JBL 2234 with your TAD 1601 yet?
    Im wondering which woofer sounds better to your 1khz crossover?

  10. #10
    Senior Member RMC's Avatar
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    Slot type vents




    I certainly don't intend to de-rail the thread but I do note no one has answered here since the last picture was posted days ago...

    I'm of the opinion that slot side wall vents give a low-frequency cabinet better appearance than tube ones as shown here. I'm mostly interested by the very good looking LF enclosure having narrow vertical side wall vents on the baffle. They seem convenient to make efficient use of front panel space available. They also tend to minimize the perceived appearance of vent size (less gross) VS the big hole(s) in the box...

    I see these vents from time to time on commercial and DIY cabinets. For example, the small Genelec studio monitors 1030A (6.5", 80W) and 1032B (10", 180W) both have slot vent on each side of tweeter, not wall sided though, and their look isn't as nice as here in my view. Plus those small speakers are not as large air movers as the woofers in the post.

    I estimate the vents seen on post # 16 to be about 1" wide and 15" high, so about 15 sq.in. each, or the equivalent of a 4.4" diameter port. Not far from JBL's minimum recommended for a 15" driver (i.e. one-third of the 15" woofer's diameter). Also power input related. Their latest advice is to use the largest port area that will practically fit in the box, makes sense with the ever increasing output of more modern woofers.

    As a form of rectangular vent, slot ones are ok in principle. Vent shapes like square, rectangle, round or triangle usually don't present a problem. However, narrow ones seen on some enclosures have been a question mark in my mind for a while, certainly not regarding the nice look they give to a box!

    I've always wondered about their good or less so? acoustical performance, more so when the narrow slot includes one or two cabinet walls. That concern I've had about them is probably why I never dared using such. Prudence has made me keep vents away from walls as often as I could. They could work as well as others or not, I wasn't sure about this.

    In normal home use sound levels these may not present an issue at all, but what happens as power goes up markedly? In the example seen two relatively high power VLF drivers are used, possibly in parallel, and these drivers can move a sizeable amount of air. Will that port's width cope adequately with the large air flow? Is the vent located to avoid turbulence or are slots prone to port noise or whistling at high level?

    Since I haven't used such ports up to now, I looked into my speaker building stuff to see what JBL and others had to say about such vents. As expected, location of a vent is GENERALLY not critical, but some manufacturers seem to have a preference.

    Fane Acoustics (note 1) says ports should be located near the drivers, and between these when multiples are used. Based on their image shown a slot vent would be horizontally oriented and located between both woofers (in the present case it would be impossible re cab baffle size). In E-V's doc, there's no mention about vent location, however out of five box plans with double woofers, four of them have the vent(s) somehow placed between the woofers (note 2). On JBL's HLA Series 4897/A, very high output LF cabs the large aerodynamic vent is also placed between the two woofers.

    Fortunately, JBL provides a little more insight with regards to vents including 1-2 walls. After stating that if required "insulation should be removed from the immediate vicinity of the port end", it goes on to say that "... as long as extreme length-to-width ratios are avoided." What is an extreme ratio? No say. I have not modeled scenarios to try to get an idea. Though making such vents much wider (height shorter or length longer to keep Fb) would reduce their good looks and efficient use of space, though improving their ratio.

    JBL adds " One or two sides of the box may be used as sides of such a port, but this will cause an alteration in the expected tuning. Common wall ducts should therefore be designed to allow for some length adjustment after the box is completed." (note 3)

    Also, the presence of an unobstructed air path between the driver and the vent is mentioned. In practice, this would depend on how deep such a vent goes inside the box, as well as how high a vertical slot vent is. On the issue of where to locate the port, JBL says "Overall, it's safest to locate the port somewhere on the baffle with the woofer(s), far enough away from side walls to avoid interaction between port and enclosure wall or the fiberglass insulation on the wall." (note 4)

    "safest" doesn't mean slots are plain bad or must be avoided, but rather more like can be used with an eye kept on common wall interaction/tuning aspects, length-to-width ratio, distance and air path with driver.

    Each box designer (DIY or Pro) makes his own choices/decisions and has his reasons for doing things a certain way. These are most often as good as anyone else's, whether it be budget, space/box size, material available, complexity, look, sound perceived, etc.

    Richard

    Note 1: Fane Acoustics, Loudspeaker Enclosure Design And Construction, P.5 ( Now called Fane International, Acoustics is now their Musical Instruments Speaker Division)

    Note 2: E-V, Pro Sound facts, No. 7, P. 16-18

    Note 3: JBL, Vented Loudspeaker Enclosure Construction And Operation, P. 3

    Note 4: JBL, The Most Commonly Asked Questions About Building Enclosures, P. 3, 4

  11. #11
    Senior Member 1audiohack's Avatar
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    Like this?

    Barry.
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    If we knew what the hell we were doing, we wouldn't call it research would we.

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