something a little different

[saeman]

I've been playing around with this project for a couple of years. I've always liked the 4315's and wanted to experiment with some variations. This is the second pair in this configuration I've built. I got talked out of the first pair so I regrouped and made a second.

I had a pair of 2410/2301 horns sitting around for years with no perceived use so I decided to use them in place of the 2105 cone mid range drivers. They're too hot for this configuration and need to be toned back 3db or more. After doing that the whole configuration sounded better. The stock 3114A network is the biggest drawback to the project. The plan is to get custom designed networks built but this will take some time.

The potato mashers and mirror imaged baffles are obvious. The interior is not 4315 stock. The woofer sits in a 1.5 cubic foot sealed chamber packed full of insulation and the intended end configuration will be the 121H; to be reconed soon. In the first pair this woofer pounded out good tight base and was a noticeable improvement to the low end missing in my stock 4315's. Filling the holes now is a spare pair of 124A's. Also as fillers are a pair of 2108's. In the end they will hopefully be changed to 112H's but these baskets seem to be in the Unobtamium category.

I built the steel stands years ago to get my 4315's up off the floor. I recently drug them out of storage and put them back into service. They're 1 1/2 x 1 1/2 square tube steel with 1/4" wall and weigh near as much as the speakers.. The frames bolt on using the factory hanging mounting holes so no cabinet mods were necessary. I had them finished in Navy Blue wrinkle powder coat to match the grille cloth.

This has been a fun project so I thought I'd share it. Please keep any laughing to yourself so I don't feel bad.

Rick

[Earl K]

Hi Rick,

This has been a fun project so I thought I'd share it. Please keep any laughing to yourself so I don't feel bad.

Real Nice Rick ! ( I can't imagine someone laughing at those beauts )

I've always liked the look of the chrome ring as found on the 2301 masher .


FWIW, the 2108 ( cone assembly / "software", to use a Giskard phrase ) is ever-so slightly more dynamic than the 112 ( according to my calcs.) . That would be why ( in my mind ) it exists ( in the first place ) . It's meant to be mated with the more dynamic Pro Sound components such as you've done ( & , as found in the 4315 ) .

- ie ; I wouldn't be so quick to dump those 2108s ( I'd suggest transferring the softgoods to ferrite motors if you ever get the chance ) .

just my 2 cents <> EarlK

[spkrman57]

I think that is a great project, not just a few drivers thown together to end up as whatever!

I think this is the type of JBL DIY projects that we need to see more of.

Great set of speakers!

Regards, Ron

[saeman]

Thanx Earl and Ron:

I've talked to Giskard at length about this project, including the short-falls. Without reasonable attenuation the potato masher's scream at you. The temp fix before a custom network was to place a 16 ohm resistor across the 2410 leads. This along with a small L-Pad tweak tones it down enough to get decent results. I will never sell short the 2105 and it's cousins as it's a fine cone driver. My desires were rooted in making use of a dust collecting pair of 2410/2301, in a small compact monitor and a 4315 variant was an easy target.

Putting the 121H in a sealed box yielded a night and day difference in low end response. I hope to get one of our forum wizzards to run me some curves in the future.

I won't dump the 2108's. I have a fresh pair of cones waiting for the day I find a pair of 112H/2108H ferrite baskets. Never say never but I'll likely be using the alnico 2108's for a long time.

I hope to keep these as living room monitors but my wife has already raised her eye brows over the black ash cabinets and dark blue grille cloth. The first pair was white oak with brown grilles - a better match for her furniture.

[saeman]

For anyone interested in pursuing a similar project I'll post a bunch of pics on the construction.

Pair #1 started from a pair of baffles already cut for standard 4315 layout. I overlaid the 2301 cutout template over the 2105 hole and modified the baffle. The hole already cut for the port tube was enlarged to allow my hand thru it to reach the network mounting screws and was covered with a grain matching plug afterwards.

The woofer chamber top had a removable hatch in it to allow getting the 3114A network into place - hatch cover mounted after installation. This design was poorly thought out and required a ton of extra work. On pair #2 I made the partition between woofer chamber and upper cabinet solid and cut an access hatch into the cabinet back.

The studs mounted in the cabinet divider allow connection between rear terminals and the network and between the network and the 121H - bolted in solid, sealed and thread locked.

I braced the hell out of the woofer chamber, not knowing for sure what the minimum might be. Braces were left over baltic birch fab'd into 1 1/2 x 2 1/2 form. They cost me so much internal volume that I had to pack the chamber full of insulation to make up the difference.

All in all they sounded pretty good - but - they were still running on stock 3114A networks. Before I could really complete the project they left town. I said they were keepers but money talks and bull poop walks. Thus - pair #2.

[saeman]

more pics

[saeman]

more pics

[saeman]

I didn't take any pics of the inside details of pair #2 but they are similar. Also there are no plans so if someone wants to something similar you'll need to do what I did - build the boxes and fill in everything inside.

[JeffW]

What treatment are you using on the blue baffles, is it stain or dye or...?

[saeman]

These baffles are white oak with a water based blue stain applied after using a grain sealer coat. Finish coat is 6-7 coats of satin lacquer over the top. I have used white ash before which yields a lighter brighter shade of blue. The white oak is something I had that needed to be used up.

[BMWCCA]

Beautiful work, as usual! I love your creativity and willingness to explore alternate aesthetic schemes.

Got to say I'm happy to partial to your black-ash baffles.

[saeman]

I'm partial to the black ash on the baffle too. All told - 4 pairs of 4345's scattered between Japan, France and the U.S., and I've done a couple other models with black baffles also. It looks pretty cool on the exterior too.

[tweeter]

Saeman, nice wood work.
I´ve learned pretty much about building cabs by looking the pics.

[yggdrasil]

Very nice work Rick. As always! Keep 'em coming.

Johnny

[LE15-Thumper]

People that can do that quality of woodwork make me sick..

Jealousy is awful thing isn't it ?

Freakin gorgeous, that's all I can say...