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Thread: Discussion Thread JBL 4343 to 4344 upgrade

  1. #31
    norealtalent
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    [QUOTE=porschedpm] I think one of the bigger challenges, though, would be getting a 4344 vertical foilcal produced. Unless your willing to go nude in this respect.

    I can get foil cals done in .022 stock without serial #'s for about $50 a pair when ordering 10. I had some done for 4343's. Of course an original is required to make a copy.
    Edit: Nudity should be reserved strictly for the use of "buttcheeks." Whether they be small, medium or large is by personal preference. I prefer them all... nude, of course.
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  2. #32
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    Quote Originally Posted by Lancer
    Ouch!
    We've discussed the 5234A and 5235 before along with how to improve them. One can easily hear why JBL used passive high pass filters in the BX63 and DX-1 once they hear a 5234A or 5235.
    Yep,

    Well as stated in post 13 by adopting a system this approach ensures the system bring the some of all components does infact add, not subtract to total performance improvement.

    I tend to think this in many ways is what implementing and getting the best out (not designing per say) a hi performance speaker is about.

    It is easy to modify and go the minimalist route but not end up with the right specification.

    But if engineered correctly one can extract the right level of performance.

    I bought yesterday some 0.018, 0.12. , 0.33 , .033 polystyrene capacitors to build an 18 db unity gain crossover. These are very large values of this kind of capacitor. I also intend to try charge-coupling the small signal electronics.

    These parts will also be used in the 5235 cards to assess improvements to the 5235 crossover. I am sure there are members out there who will desire a better way of bi amping

    I want avoid using the term tweak in the project. It conjures up the impression or interpretation of modification or change in the specifications and is too general. Tweaking is often a change to ones liking (not to be confused with taste but rather wanking) rather than a technically desireable improvement.

    Of course one can individualise what steps will be taken to update to 4343 per the project framework.

    Ian

    Below is a distortion graph of a new prototype active crossover. The 4344 crossver will be less is more (better again) and built for the purpose.
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  3. #33
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    [QUOTE=norealtalent]
    Quote Originally Posted by porschedpm
    I think one of the bigger challenges, though, would be getting a 4344 vertical foilcal produced. Unless your willing to go nude in this respect.

    I can get foil cals done in .022 stock without serial #'s for about $50 a pair when ordering 10. I had some done for 4343's. Of course an original is required to make a copy.
    Edit: Nudity should be reserved strictly for the use of "buttcheeks." Whether they be small, medium or large is by personal preference. I prefer them all... nude, of course.
    Very good, we will have to keep you in mind.

    Ian

  4. #34
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    Quote Originally Posted by Tom Loizeaux
    I think we should remember that the 4343 was designed for mixdown studios and, though it could be used vertically, was primarily made to hang horizontally above the board! The baffle layout was made rotatable to allow these orientation options and was probably compromised slightly due to this. The 4344 didn't have these requirements. Also, the 4344 came a bit after the 4343, so any new technical understanding could have influenced the subtle changes (or refinements). Some of these new understandings were seen in driver and crossover improvements.
    Though I don't hear any significant defficiencies in my 4343s, I have thought about how I might improve things if I were to build an updated pair.
    I think I would basically go for the 4344, but would have to consider other questions...like the idea of using a pair of woofers in each cabinet to improve and tighten the low end. I suspect the 2123H would be a stronger mid driver. Maybe a wood horn, or even going to a 1.5 or 2" throat and a 4" diaphragmed driver... maybe even the TAD 4001...? (I suspect the 2405s would stay though)
    Ah, see how it all grows?
    Maybe simply rebuilding my crossovers for the mid/high/UHF sections in my 4343s would really be enough. ?

    This is why I look forward to the development of this thread!

    Tom
    Welcome Tom,

    Don may be able to confirm this but the 4344 was sold largely in Japan for the domestic audiophiles over there. A sub like the 1500 may be a worth option..Lancer may have input on the as things pan out.

    About the steps to improvement, I don't think we need to take extreme measures. Of course a rebuild of the enclosure would be an option if you prefer to keep your original 4343 as is.


    Ian

  5. #35
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    Documentation with references to both the 4343 and 4344 is an important part of the project.

    If someone can post some links (ie the library and key threads & posts, jblpro.com, 4343 reviews) we will have a means of accessing important data.

    I know myself I have previously posted some drawings and other also, so we need to locate and review these posts.

    Thsi information once verified can be posted into the design thread. will start on this over the weekend. I suggest we all have a look around and come back with some links.




    Ian

  6. #36
    Senior Member saeman's Avatar
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    4344

    Hello Ian: Please take a look at the enclosure cutaway that I am planning for my hybrid 4344's. It's to approximate scale but just a sketch. My plan is to provide a recessed area at the upper rear of the cabinet to house all of the electronics related to the crossovers. All components, with the exception of the baffle mounted pots, will be outside of the pressure hull. I may leave this area open or possible provide a removable cover. To make up for the loss of internal volume I increased the cabinet depth 2". The resulting internal volume is near identical to the stock 4344. From the front it's height and width will look identical to the factory 4344. My question is "To all of the custom x-over guys out there" - Is there enough room in this area to house the necessary x-over components - coils, caps, gadgets, dugans, etc. ??? Assuming replies to the positive, I want to push on cutting wood and making the cabinets. Thanx in advance - Rick

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  7. #37
    Regis
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    Very interesting Rick and mounting the crossover outside would make it easier to do mods on the X-overs, plus you'd have unlimited room out the back. I'm curious as to how you'd run the wiring from the external to the internal and whether or not it would have to be sealed or would you use connectors (like we do in areospace) through the 'bulkhead'? Secondly, if externally mounted, would you go with some kind of wire cage to protect the passives from any thing falling into them? Hoping a little forward thinking before cutting would help (even with my limited experience).

  8. #38
    Senior Member saeman's Avatar
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    Quote Originally Posted by Regis
    I'm curious as to how you'd run the wiring from the external to the internal and whether or not it would have to be sealed or would you use connectors (like we do in areospace) through the 'bulkhead'? Secondly, if externally mounted, would you go with some kind of wire cage to protect the passives from any thing falling into them?
    Thanx for the thoughts. For the wiring to the three pots I would use a single Beldon type multi conductor cable, like JBL uses, and a single penetration into the cabinet using a compression type connector. For the wiring to the four components themselves I thought an array of threaded copper studs thru the back might be a good thing. Arrange them 2 wide x 4 high, a pair for each component. They could easily be sealed at their point of penetration and nuts/ring connectors would ensure a good low resistance connection. Just my thoughts at this time. Keep in mind that I don't know diddly about custom x-overs.

  9. #39
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    Interesting idea Rick,

    Your design criteria has many of the ingrediance that "we" discussed when evolving the reference system for Ed.

    When we thought it through it became clear that a new 3145 network would best be external to the crossover The reason is where would the network go in inside the enclosure and we wanted to leave the original crossover/wiring/L pad entact per Ed's comments above? That is the changes should be reversable(the Pads would have to be replaced for the 3145 network)

    Secondly, how to organise the wiring to ensure a neat air tight seal and avoid the phase errors that can easily occurr with a 4 way system. What I came up with was a nice 8 pole speakon sock and plug . This plug accepts up to 13 gauge wire.

    The solution was an external crossover about the size of a PL mini tower with the L pads on the front of it.

    I like your idea but it will require a re build of the enclosure. There would appear enough surface area.

    Are you making your from baffle removeable or the rear panel?

    Ian

  10. #40
    Senior Member saeman's Avatar
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    Quote Originally Posted by Ian Mackenzie
    Are you making your from baffle removeable or the rear panel?
    Ian: Neither the baffle nor the rear panel are removable. They are glued solid into the sides, top and bottom. Why do you ask ?

  11. #41
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    Rick,

    I will post these drawing at least temporarily for you to down load.

    Please check the dimensions for accuracy before cutting.

    Ian
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  12. #42
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    The other drawings are here.

    Ian
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  13. #43
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    4344 Dwg's

    Ian: Thanx for the drawings. I think I downloaded most of them from one of your earlier threads, however I just downloaded them again. On these details I do not see the depth of the mid-base box or the diameter of the two baffle ports. Is this info listed elsewhere?? Thanx - Rick

  14. #44
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    Here it is.

    I am not sure about the port length....I amsure its around in one of the many threads earlier on

    Ian
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  15. #45
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    Quote Originally Posted by riessen
    Ian: Neither the baffle nor the rear panel are removable. They are glued solid into the sides, top and bottom. Why do you ask ?
    Well some how you will need access to the compression driver and slot otherwise it will be almost impossible to remove the driver if it requires servicing.
    The same applies to the 2405.

    I don't know about the 4344, but the 4343 had a removeable front baffle and the 4345 has a removeable rear panel for this reason.

    Ian

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