4320 Project

[hjames]

Thanks for the tip! While talking of crossovers in other threads, Giskard has said to just stack up 10w resistors to get the higher wattage numbers - so I ordered all 10 watt resistors. Worst case, maybe I'll have a few too many, but they're the cheaper part of the networks.

Anyway - thats next weekend's job - today is dedicated to building grilles.

The speakers didn't have any grills when I bought them, but the basic design is similar to one I saw in one of Zilch's pictures here: http://audioheritage.org/vbulletin/s...75&postcount=1

Last weekend I got one of those $99 Ryobi table saws at Homedespot, and a 60 tooth finecut saw to put into it instead of the default 24tooth saw it came with (basically, more teeth = finer cut). I thought we'd get rain this weekend so Friday after work I got the parts sawed out. But Saturday was a clear day. I glued and pinned the wood together, and cut 8 mid-side spacers - then put them into position. Everything went so well that by 4pm I had time to l spray them with flat black paint and I'm ready to glue the grill cloth.

For cloth options I've got a light tan (similar to L300 color), black, and some of the JBL Blue cloth I got from Zilch (which looks black but is actually more like Navy blue). We decided to pass on the black, but we can't figure if we like the deep blue or the tan - the speakers will be up on the shelf and partly block the window - so the light color may be more appealing. Anyway, as you can see in the botom picture, I loosely covered one grill with each - and we'll look at them for a week or so before deciding which one to glue into place.

[Chas]

Nice work on the grillle frames. I have the same cabinets as you have - that were originally grey and I use the S-22-2 guts inside, but I refinished mine in melamine black (hello-Ikea?). Also, I added integral bases to get the mids and highs at ear level, when I am seated. I can't post pictures because I am hopelessly incompetent with regard to the criteria set out for posting, but I could e-mail copies....

I'd really love to have a set of grille frames, if you have some spares. I would be willing to compensate you.....Good luck with your project, I don't think you will be disappointed. Your time invested, will be well worth it.

[hjames]

We decided the JBL Blue was the only way to go - it just looks so much richer than the L300 tan I thought might be useful. I took some time this morning to cut the Zilch-cloth in half and do the glue and trim work - maybe an hour, all told. I think they've worked out quite nicely, tho they are a real tight fit, I still need to add some velcro to the back for added security (the original metal spring clips were broken and worn - hard to get out but - they're gone). I added the consumer-style JBL metal logo badges just for fun.

This was my first time out making grill frames - think I'd use a better brad nailer to pin the corners together next time. I may yet make a second set so I can truly compare the tan cloth once I get the speakers up in the corner, and if I do, I'll let you know, Charles, but right now I'm a bit shy of making these for others ...

[JuniorJBL]

Nice job Heather!!

Kind of OT but if you need your saw to cut bigger pieces of wood go to an 8" blade and you will find more power than with a 10" blade

[Zilch]

Beautiful!

Gotta LOVE that blue....

[Tom Loizeaux]

Heather, nice work!
A pair of 4320s were my first speaker restoration project.
I suggest you condider buying a pair of 3106 crossovers for the slot tweeters, especially if your cabinets already have cut-outs of these.
The other approach, of course, would be to tri-amp your 4320s.
A 3-way stereo electronic crossover (and 3 stereo amps) would let you tweak frequencies and balance of your drivers.

Tom

[hjames]

I just ordered the parts to build Giskard's 4333/S300/L300 equivalent bandbass circuit - (the regular, not the Charge Coupled design) see - http://audioheritage.org/vbulletin/s...42&postcount=3

Well, I got my Parts Express order for the caps, coils and resistors last weekend - and took a few nights to wire up crossovers per Giskards 3113B equiv. circuit for the L300s so I didn't need center tapped coils. I finished them Thursday and hooked them up for a trial for the last couple nights - they sounded very nice with quite amazing bass. They sounded nice enough so I decided it was time to finish the project. This morning I laid the speakers on their backs and pulled the 2215 Woofers to get room to work. I put the crossovers inside the cabinets, with a pair of short wood screws to hold them to the side of the cabinet.

Then we lifted them up on top of the shelves. Ugh - these things are heavy MONSTERS.
I was hesitant to set them base down on the shelves because the tacked on base (foot?) was a bit wider than the shelf
and that would put a lot of weight on two skinny little strips of wood (just the sides of the foot).

First listen - hey - where'd all the BASS go!! I tried that Jennifer Warnes song "Way Down Deep" ("The Hunter" CD) - the BASS is there,
but more subtle and less in your face - I sure got spoiled with these speakers on the floor so close to the sofa ...
Speakers must be like real estate: location, location, location ... pity they can't stay on the floor, but, there's no room!

I'm going to listen for a few days or so to see what I think long term - but if I keep these speakers on their side like this I ought to rotate the 2405 slot tweeters (and the 2308 lenses for the horns) 90 degrees.

Or - I may turn the cabinets another 90 degrees instead - Woofer on top (as I've seen them hung upside down for studio use in some pictures)
If I put them on top of the shelves upside down, the flat top can transfer the weight better and be stable on the shelves.


Anyway - here's the current component list ...
4502 Enclosure
2215 15" woofer
2420 MF driver with 2307 Horn and 2308 lens
2405 HF driver (new to unit)
3113B equiv crossover networks (Thanks, Giskard!!)

the pair of 3110 Crossovers have been pulled and will be for sale soon!

[Titanium Dome]

Congratulations! Well done.

[Tom Loizeaux]

It's great to see people bring these things back to life. Well done!

Working them on their sides can be OK, but you should turn the 2405 slots to vertical. I don't know if there is enough room, but try to mount ther 2308 lenses horizontally.
I had mine on the floor, with the same componants as yours, except that I used the 3110 and 3106 crossovers...and they sounded very nice!

Tom

[hjames]

My speakers currently have 2215A Woofers - which I gather are not rebuildable in their current form. Would it be reasonable to buy a pair of 2220A woofers to have as spares for the sad day when mine go flat?

[Zilch]

I'd be hoarding a pair of 2225H in need of recone to make into 2235H when the time comes....

[hjames]

So the 2220A's don't have the same core value then, even if I get them cheaply? They can't be reconed into something more current?

I'd be hoarding a pair of 2225H in need of recone to make into 2235H when the time comes....

My speakers currently have 2215A Woofers - which I gather are not rebuildable in their current form. Would it be reasonable to buy a pair of 2220A woofers to have as spares for the sad day when mine go flat?

[Zilch]

There's several threads in these forums on cone interchangeability, but 2225 is the exact same ferrite-magnet core as 2235, and therefore the best choice. Once reconed, you end up with an "as-new" 2235H.

They're also plentiful, and smoked ones are sometimes available cheaply when users upgrade to 2226H instead.

I'd hold off on doing the actual recone until I needed them, so my "new" ones had fresh foam at that time....

[speakerdave]

. . . .Or - I may turn the cabinets another 90 degrees instead - Woofer on top (as I've seen them hung upside down for studio use in some pictures)
If I put them on top of the shelves upside down, the flat top can transfer the weight better and be stable on the shelves. . . . .

I've enjoyed reading about your work on this project. Your enthusiasm and your way of getting on with it have inspired me to get out in the garage and make some sawdust myself.

I would think that on their sides would be best because that is the position in which the one tweeter will be lowest. That 2405 tweeter has a fairly narrow vertical dispersion (16kHz is 6 dB down at 15 degrees off axis). It would be worthwhile to cut another tweeter mounting hole in one of the cabinets on the opposite side of the midhorn so that you can have true mirror imaging in the horizontal orientation with the tweeters lowest, and experiment with turning the fins on the midhorn so they angle up and diffract down into the listening area.

Also, I wouldn't worry about wearing out the LE15's, but if something should happen to them, the woofer to replace them would be the 1500Al. You could start a little fund right now and have the money when you need them.

Additional Note (for other readers): You've been referring to the 3113 crossover; I assume you mean the 3133.

David

[hjames]

I've enjoyed reading about your work on this project. Your enthusiasm and your way of getting on with it have inspired me to get out in the garage and make some sawdust myself.

I would think that on their sides would be best because that is the position in which the one tweeter will be lowest. That 2405 tweeter has a fairly narrow vertical dispersion (16kHz is 6 dB down at 15 degrees off axis). It would be worthwhile to cut another tweeter mounting hole in one of the cabinets on the opposite side of the midhorn so that you can have true mirror imaging in the horizontal orientation with the tweeters lowest, and experiment with turning the fins on the midhorn so they angle up and diffract down into the listening area.

Also, I wouldn't worry about wearing out the LE15's, but if something should happen to them, the woofer to replace them would be the 1500Al. You could start a little fund right now and have the money when you need them.

Additional Note (for other readers): You've been referring to the 3113 crossover; I assume you mean the 3133.

David

Thanks for the kind words - you've inspired me tonight!
I reached up and loosened the mounting screws so I could rotate the slot tweeters 90 degrees. Maybe another day I'll pull the left cabinet down off the shelf and bore another mounting hole to allow moving one of the slot-tweeters and make them mirror image cabinets, but at least tonight, the slots are vertical.

I also took some of the leftover 3/4x 1" stock I ripped off the wood for the grills and made 4 1/2" long "rails" that I can velcro to the back of the lenses. The woofer frames extend nearly 1 inch out from the baffleboard and interfer with the lenses when I tried to rotate them 90 degrees.
With the rails to offset them from the baffleboard, the leses should be able to clear the edge of the woofers.
Sounds more complex than it is - I'll take a picture once its done.

And yes - I probably do mean 3133B crossovers - heck - I called my speakers 3420 in at least 2 messages before I realized I'd transposed the digits - dislexia means I shouldn't type when I'm tiired ... sighg.