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Thread: New Custom Cabinets for LE14H-3, 2452H-SL and PT-F95HF

  1. #1
    Member Duffinator's Avatar
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    New Custom Cabinets for LE14H-3, 2452H-SL and PT-F95HF

    Hi all, it's been a while but I'm about ready to redo my custom ZD-007 speakers that Zilch help be make back in 2007. Some of you may remember these from the eWave threads here and on Audiokarma. They are in Barzilay cabinets that I've modified with battens and bracing to help reduce the resonance from the cabinets. I never felt the cabinets were doing the components justice and I've wanted to make new cabinets from the beginning but never had the time or skills to do so. I recently retired and a good friend of mine also recently retired and now we both have the time and he has the skills to make the cabinets. I'm using a custom crossover that Zilch designed based on the 4430 and made changes as he typically did. I don't specifically remember what the changes were.

    For the new cabinets I have several questions that I'm sure the vast knowledge here can help me with. The reasons for building new cabinets are to tighten up the bass and improve imaging and sound stage with a properly designed cabinet. While bass is very important I'm willing to give up some lower extension for tight bass. I listen to mostly rock and pop music that has a lot of guitars and string instruments. My system is in a relatively small room that's 11'x12'. For the design I'm using my 4425's for inspiration along with 1400 Array's. Here are my initial questions:

    1. The initial design has interior dimensions of 33" high, 16" deep and 13" wide yielding just under 4 cu ft of volume. What is a good volume for LE14H-3?
    2. The cabinets will be made of MDF. What is a good thickness? I was originally thinking of 1.5" thick but maybe that's overkill?
    3. For whatever thickness I make the cabinets should they be braced? See initial brace design.
    4. In the initial design I have the waveguide mounted on a 3/4" plate similar to 4425/4430. The guide will be recessed in the plate and exposed. This could change depending on the answer to this question. How close should the waveguide be to the woofer frame. Zilch wanted them as close as possible.
    5. What's the ideal depth between the woofer and CD? (time alignment) Is flush mounting them fine or should I try and optimize the depth between the two? See above about moving the waveguide further forward with a plate.
    6. I'm planning on using two 3" ports. I could use one lager port but using two allows me to fine tune the bass as needed. Thoughts?
    7. While I'd like to use the same components I have is there a better waveguide or CD for this application? I could add a UHF driver but that will be for another day.

    Thanks in advance for any answers comments or suggestions you may have.
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    Member Duffinator's Avatar
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    More images
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    Administrator Mr. Widget's Avatar
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    I’ve been out of the DIY game too long, so I’ll let others advise where they can, but I think your Econowaves look very nice as they are... I will comment on your acoustic treatment. I assume those are fiberglass panels behind the speakers. Assuming that is correct, they won’t be very effective where they are. About 50% of their area is covered by the speakers themselves and the rest is directly behind the speakers. If you can move them to the side walls just a bit forward of the speakers you’ll likely improve your imaging.

    Assuming you didn’t make any gross errors in the port calculations and bracing, you may not have all that much room for improvement in the box department. To tweak your bass, I’d look at room placement and possibly EQ.


    Overall, a pretty nice system you have there.


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    Member Duffinator's Avatar
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    Thank you.

    The room is a bit challenged. I have two more of those panels on the other side of the room mounted up higher on the wall. They were an afterthought. A friend of mine removed them from his HT and I quickly bought them. He regretted that and bought replacement panels 2-3 months later. The room has two doors to the left and all windows to the right and is far from ideal.

    Aesthetics aside I want to see what a more contemporary designed speaker cabinet can do for the components. The Barzilay cabinets are just a big thin box that I added some bracing to try and reduce the resonance.

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    Administrator Robh3606's Avatar
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    They look nice! On the new cabinet I would watch that side to side brace. The diamond looks small and you don't want an undamped panel close to the back of the woofer. Also how long are your port tubes?? Don't want them too close to that same brace. Might want to cut holes.

    Rob
    "I could be arguing in my spare time"

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    Senior Member grumpy's Avatar
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    Might want to give this a look for fun:

    https://sound-au.com/bafflestep.htm

    I don’t expect you’ll be able to sneak it in at the crossover frequency (a trick to take advantage of difference in driver sensitivity).

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    Member Duffinator's Avatar
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    The baffle step info looks interesting, I'll try and digest it.

    The bracing has been through a few iterations and attached are the current.

    So I'm still looking for optimum size of the cabinet and port tube length for twin 3" ports. Any suggestions?
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    Administrator Mr. Widget's Avatar
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    Two comments on the current bracing... actually, one is about the current bracing and the other is about bracing in general.

    1. I think you need mid span braces, struts that are mid point on the sides and front and rear baffle and cut straight across. Yours are now mostly simple rings that will not offer much benefit.

    2. This is for all bracing. Never use MDF as a brace, the stuff is as structural as a wet noodle. Use a doug fir 2X4 or Baltic birch plywood, or some other wood that has structural integrity. (stiffness)


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    Senior Member Ian Mackenzie's Avatar
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    Have you looked at the Array 1400 Series featuring the LE14H-3 with an enclosure volume of 3.2 cu ft3 and 31 hertz tuning.

    Jbl in particular Greg Timber’s know a thing or two about setup a driver for success.
    I simulated the Array 1400 and compared to to a maximally flat tuning.

    Consider an enclosure profile so your horn is at ear height.
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    @Mr. Widget, good tips on the bracing. We had another design that had more cross bracing, see attached, and will create another version.

    @Ian, I'm using 1400 Array as inspiration but couldn't find the volume so that's very helpful. So it looks like I should lower the volume on my cabinet. While I won't bet getting the waveguide at ear height it will be about 6" higher than it currently is so that should be an improvement.
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    Senior Member Ian Mackenzie's Avatar
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    Every tip helps.

    Nice

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    Administrator Mr. Widget's Avatar
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    I think this bracing will be better. Can you extend your vertical that stops about 1/3 of the way before it gets to the bottom all the way to the bottom? That would help.

    Maybe tilt the cabinet or angle the baffle to aim the HF towards your ears?


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    Member Duffinator's Avatar
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    I found the specs on the JBL S4600 which is pretty close to what we're building. If pretty much validated everything were doing including the tuning at 35 hz.
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    Here's the latest and this should be close to the final iteration of the design.
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  15. #15
    Administrator Mr. Widget's Avatar
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    Looking very nice.

    Two points regarding the JBL exploded view.

    1. Realize that the bean counters at Harman trump the engineers.
    2. I can’t stress enough that you should avoid the temptation to use MDF for your bracing.


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