Heather's new L200 JBL Dynamics Project

[hjames]

Just a starting post for this JBL thread. Ages ago, circa 2006, thanks to @BigYank, I won a pair of 4320 2-ways.
https://www.audioheritage.org/vbulle...l=1#post100289
I moved into some L200B cabinets, grew them into 3 ways, switched from the exponential horns to some JohnW smith-horns,
and then moved them on around 2016. Sold them off.

The sale made sense at the time, but I've since decided I liked that sound and want another pair. Well, with some updates.
Folks have been talking about updating older designs with the 2016nd 15" woofer, and - others have said the L200 Cab design is old,
not the best, and it would be better if the woofer was higher from the floor.
Heck, in 2011 Nelson Pass posted a design for a "Nelson Pass styled L300 Summit Crossover" which he thought was a good compromise
to update the famous JBL 3-ways (which many of us tried to update our L200s into in one way or another).
Other folks are saying passive crossover designs are badly dated and active crossover and biamp or triamped design is really the way to go.

Darned if I know which is best, or what I will prefer here.
But to facilitate my 2022 JBL Project, I've been collecting parts. Found a pair of JBL 2216ND Woofer (for JBL M2) via Speaker Exchange in FLA.



While I was throwing out ideas on the project on AK, Jeff PMed me and said he had a pair of horns like mine that he wasn't using - make an offer (!).
We settled on a fair price, he packed them "bomb-proof" for the trip to me in VA, and, a nice pair of mahogany JohnW Smith horns are now here in VA.
Funniest thing is JohnW made them for Dhar here in the DC area, then Dhar sold them to Jeff in Texas! Now from Texas back to DC area. Such a round trip!


While that was going on, I found a pair of 2445j drivers and made a fair offer on eBay for them & also got the 2328 Horn adapters off Reverb.

Subwoof and others said they could sound harsh, and I'd likely prefer a newer pair of coated diaphragms, so I got the JBL D8R2452-SL Diaphragms,
again, via Speaker Exchange.

Did my first time large format diaphragm install, used a tone generator to center them as I reassembled the drivers, then bolted them to the Smith Horns.


I still have a pair of Heathkit branded Altec Valencias (my LAST project) in the living room, for sale, so I tied some LPads across to the 2446 drivers,
did a cheesy quick & dirty hookup in parallel to the Valencias, turned down their horns, and have them running now.
Def not perfect, but I can tell they work, and that the new diaphragms are a great improvement over the original 34 year old TI dias.
I got a pair of the "Nelson Pass style L300 Summit crossovers" online. I'm sure they're not the best caps,
but they are built on a nice etched PC board, which saves me a lot of time - so all I need are the 2 LPads for Mids and Highs,
plus a pair of 5-way jacks for inputs, and 3 pair of jacks for the outputs (Lo, Mid, hi).
So, it makes sense to build the crossovers in external cabinets that I can put on top of the woofer cabinets, just under the horns.
If I decide to go active later, I can sell the 3 ways easier in a nice box than just as wired parts removed from the main cabinet.


So, that was this week's project. I'm the first to admit I am not a cabinetmaker or any kind of woodworker, but I do the best I can.
Got some 1x3 poplar planks from Home Depot - figured a good dimension would be 10 x 16 - so it could be under the horn, LPads on front,
and it could function as a nice support for the smith horn. Cut lumber, mocked it up, and after I glued them up, Checked them under the horn.


I do have a pair of nearly new Great Heil subwoofer, that could easily sit on top of the smith horns and still be at ear level.

[hjames]

Once I got the mocked up crossover boxes in place, I realized the adapter lip for the horn to adapter transition
would limit the front-to-back position of the driver on top of the main cabinet.
(The 2445j drivers came with a beefy metal mount that supports them - and if I use 18" x 18" granite tiles
as cabinet toppers, that support bracket needs to sit on top of it,
and I didn't want to have to slide it to the back edge of the granite topper.

Couldn't see any way around it, so I knocked down the boxes, recut the side panels, and just glued it back together as a 7 x 16 box.
I'll let it dry overnight, then trim the box bottom with a router (got a roller-bearing bit on the way from Amazon sometime today).
Not sure if I'll need a top, but I do have some more of the wood panelling I can is I do.
I've got some rubber pads I stripped from some cork isolation blocks I've had, and I'll glue them to the top and bottom of the crossover boxes
just to protect the mahogany Smith horns

Once the boxes are built, I can mount the jacks and LPads and solder them all together. Later this weekend, as time allows.

The main design for the woofer cabinets is 5 cu ft. boxes of Baltic Birch. More details on that, and the gentlemen building them for me in a later post.
(Like I say, I do the best I can but I am no woodworker nor cabinetmaker!)
I do have some tools, and a shopmate folding workbench I rigged up with interchangeable benchtops I made for a Table Saw, and a mitre saw I bought years back.
But - we have a small house, no garage of basement workshop - so when I use the power tools, I set up in the backyard under a magnolia tree ...


The smaller box mockup - design and visual look.

[Robh3606]

Hello Heather

Nice to see a new DIY project on the forum. Active vs passive that's a hard question considering you can get great results from both. Doing your own custom cabinets is certainly a much better idea than trying to re-purpose a pair of L200 cabinets. In 5 cubic ft with 2216nd's you certainly have a "window" and some flexibility to tune the boxes depending on what you want to do and what works best in your room.

I still have my HEIL's can't say I ever thought to use them in a large 3 way. That could be a lot of fun. A supper 077 Slot with built in adjustable rear ambiance.

Keep us posted!

Rob

[spkrman57]

I need to get my 1501Fe, 2206J and 2445/Be on 500Hz round Edgarhorn. Biamped between 1501Fe and 2206J so I can use Single ended tube amps on top and SS on LF.

Your system is a inspiration for me.

Thanks, Ron

[rusty jefferson]

If I'm reading the dimensions on these drawings correctly the 846A is 5.7 cubic feet empty and the 4367 appears to be about 5.5 cubic feet.

https://www.google.com/url?sa=t&sour...53ywEy7QjYonWn

[hjames]

Next step done. Drilled, stained & assembled the slot boxes and put them into place. Vertical, of course
(tho I haven't built the new xovers yet, still on the so called Nelson Pass style design,

The initial slot tweeter addition seems like an improvement over the Heils with this crossover,
tho not exact, its closer to the driver config of the L300 crossover design ...

But ... there is a new Christmas tree in the middle of the sound field!
... long as it sounds good by my birthday in February, I'll be happy!

[hjames]

Well, the fact is that I don't actually own the Valencia speaker cabinets yet so I can't measure the interior.
I DID have a pair of Heathkit Valencias I was modding for quite a while but sold them about a year ago.
I've been offered some empty Valencia cabinets and I'm trying to discern if they are a reasonable box
to use for the 2216ND speakers I do own before I go through whatever logistics are involved in obtaining them.
That said, it does sound as if they're of a volume that'd work for this project.

[RMC]

Quickly.

Though the math is right for ext. box dimensions/volume, the assumption it might lead to a 4-5 cu ft internal volume sounds like "creative accounting" since it would represent approx a 50% box size reduction from the 9.32 cu ft. Overly optimistic in my view, likely more than 4-5 cu ft. internal. Sorry. Two options to make this more realistic.

1- Measure internal dimensions (if possible), then do the same calculations as before, after that subtract about one cu ft for volume displaced by woofer and bracing. This will give a closer actual Vb figure of the dedicated box.

2- In absence of internal dimensions and/or of an accurate panel(s) thickness number(s), assume 3/4" material and calculate/add the volume of each box panel to get a total number for these, this is to be subtracted from the 9.32 cu ft since it was an external box volume. Moreover subtract about one cu ft for volume displaced by woofer and bracing. This will also give a closer to real life cab volume figure.

Some panel overlaps may make the calculations a bit more tricky but these should be quite small numbers of low impact, so nothing to lose sleep about if they're not fully or correctly considered in the calculations.

[macsic]

Hello,
I tried to integrate the Heils which I had taken on my ESS AMT-1A Monitor during the reconstruction of their crossovers, tests with a system using 2450/2397, Altecs 817a, I really like the Heils but I am returned to 2405 after a few months of testing of all kinds, this choice is not as obvious as I might have thought. The reason for this return is better overall integration for efficiency, if you adjust for a specific volume the Heil has a higher holographic side to the 2405 that's really their strength and magic.
Your experience could really be different with the very enviable 2216nd which have an efficiency closer to the Heil but still quite different from the 2445, experience that I do not have.
I would be surprised if you were disappointed.
Have fun.

[Mr. Widget]

Very, very cool… thanks for sharing your project with us, keep it coming!


Widget

[RMC]

I get 6 cu ft internal for an empty 846A cab, pretty close to the other result. Not easy plans to deal with and figure out some things, clarity isn't its best asset, even with the large amount of details given.

As for 2216nd suitability in such box one should model it in speaker software using various tuning frequencies in order to decide about the best outcome (LF curve shape) vs expectations or user needs.

[Robh3606]

Hello Heather

I am using 4.7 cubic ft for my 2216's They are tuned to 25Hz and I use the same alignment as used in the B380/B460. I only use +3db instead of the +6 in the BX-63.

When I was setting things up I had a 32Hz option and can run them with no LF boost and on most music they sound fine.

A larger cabinet will be fine. I am on the "small" size by design to keep the whole system size in check and don't use the volume behind the waveguide.

Might want to think about a custom cabinet if only to get the woofer "off the floor".

Rob

[hjames]

Hello Heather
I am using 4.7 cubic ft for my 2216's They are tuned to 25Hz and I use the same alignment as used in the B380/B460. I only use +3db instead of the +6 in the BX-63.
When I was setting things up I had a 32Hz option and can run them with no LF boost and on most music they sound fine.
A larger cabinet will be fine. I am on the "small" size by design to keep the whole system size in check and don't use the volume behind the waveguide.
Might want to think about a custom cabinet if only to get the woofer "off the floor".
Rob

Thank you, Rob!

Couple ideas - I tend to add wheels to the bottom of the larger cabinets I have, makes it easier to move and to clean around it, as I did with the Heath/Valencias last year.

Like I say, I don't have them yet, just thinking through possibilities if I go that route.
I did some measurements with the Heathkit/Valencias I had last year, to get an idea of the general height.
I had furniture wheels screwed directly into the bottom of the cabinet just inside the factory plinth, which lifted it maybe 1.5 inches.
The 3-way crossovers I built fit just under the smith horns, so the dimensions are pretty close to the mockups.

[Robh3606]

Thank you, Rob!

Couple ideas - I tend to add wheels to the bottom of the larger cabinets I have, makes it easier to move and to clean around it, as I did with the Heath/Valencias last year,
so I'm thinking - if I made a Plinth/footer "skirt" to go around the factory base I could get wheels under it as well as lift the woofer higher off the floor.
What do you think - lift them 8-10 inches or so?

Like I say, I don't have them yet, just thinking through possibilities. I found this stock image online.

Hello Heather

I like to do that too! I did the same thing for my 4344 clones. They are on 12" stands more in line to get the 077 at seated ear height.

I think you have a good plan and you could experiment with the height so the HEIL doesn't get too high or low like the 077

Rob

[hjames]

Put the bearing router bit in a nearly unused router, set up the shopmate out back at 9AM, and trimmed the cabinet bottoms.
Knocked the bench down, touched up the cabinet stain in a few places, then took Emma out for Dim Sum at 11:30
(Emma's choice, once a month at Mark's Duck House near 7 Corners).

Final mockup complete, parts fit checks out.
Now all that remains is the final assembly and solder work.