4345 monitor plans

[boputnam]

Hey, Earl K...

I was thinking this weekend about tossing one of the dwarfs (4301B's ) into the truck and seeing if they could match the baffle color. I don't think they're much computerized in these parts, but we'll see... Maybe Widget has the means?

Whatever JBL used, there was almost indiscernable batch effects - that color is identical on my 4345's, 4313B's and 4301B's. Same-same-same with the grill cloths.

[Tom Loizeaux]

Bo, Interesting photos. I enjoyed them.
Are those original stock crossovers? The crossovers in my 4333s and 4343s are housed in a large metal box with terminal strips and point to point wiring, covered with a perforated metal screen. I'm surprized to see that yours are different.

Tom

[boputnam]

Hey, Tom...

"Are those original stock crossovers?

Near as I can tell. I had them mostly out, and partly dissassembled, yesterday for a member's (regrettably unrequited... ) request. There is no sign they are anything other than the Real McCoy.

[boputnam]

Earl K...

I remembered a "laugh" wrt your suggestion of getting "color consulting" done...

Once time, I took a tired-old LE10A that someone had spilled something onto the face of, and went looking to try and match the old off-white Aquaplas face with some touch-up paint. This was the vintage LE10A with the fine, shiny white flecks of what look like maybe gypsum. Well, the HipHop boys manning the paint department were astounded by the size and weight of the motor, but were absolutely befuddled at, and insistant on changing, the white face. "It oughta be black, man - just not right..."

They thought I was, well, at the least, bi...

Ha!

[Ian Mackenzie]

Bo,

Regards the pics I'm impressed with your measurements.

I have one question however which may help us Slot fanatics extract the last once of HF performance.

Exactly how far proud does the lip of the 2405 Slot clear of the front baffle? It looks to be an 1/8 inch or so.

This is a key measurement given the small wave lengths at the crossover point, and may also effect HF dispersion and imaging.

regards

macka

[Earl K]

Bo, Yes, again , great effort at providing pics and measurements for the 4345. With all the other available information including crossover schematics, it should now be pretty straightforward to build up a pair ( but of course, not cheap ).

befuddled at, and insistant on changing, the white face. "It oughta be black, man - just not right..."

Well, I guess being the contrarian that I am, I prefer white cones for HiFi. (Helps keep me from getting confused & thinking that I'm listening to my black-faced SR gear - ).


I bought a mint pair ( NIB ) of ancient le10a woofs that I refurbished the LansaLoy surrounds on. Alas, I got one small dot of brake fluid on that "gypsum" faced white cone. Stained it like the dickens - the size of a quarter.

- Did the HipHop boys ever successfully match the off-white color( or get close ) ?
- Or did they manage to send you into retreat mode ?

regards <. Earl K

[boputnam]

"Exactly how far proud does the lip of the 2405 Slot clear of the front baffle? It looks to be an 1/8 inch or so."

Hey, Ian...

Sorry, for the unfairly delayed reply - I'm "moving in" to a new EQ, and, well, er, you know...

The distance from face of baffle to face of these 2405's is 25/100ths inch. I say these, because there are some slight modifications to the 2405's from this vintage to today's.

On this vintage 2405 (16-ohm), the length of the "throat" is exactly 100/100ths inch. But, you can see in the attached from the current 2405 (8-ohm) brochure (JBL Pro 2405 Component Link) the throat is 1-1/16 inch.

On the vintage 2405 (16-ohm) the mounting flange is also 25/100ths inch. I somewhere have a schematic for the vintage 2405, but it must be on my harddrive at work, and I won't be there 'til Thursday...

Hope this helps

[boputnam]

"Did the HipHop boys ever successfully match the off-white color( or get close ) ? "

Hey, Earl K...

Yea, they did. There's a kid here who has sniffed all sort of vaporous things and does a really good job matching paint.

However, each white-boy cone is it's own unique shade. Over the years they fade differently, and are colored by their surroundings (or spills... ). So, I've got 4 half-quarts (smallest batch they would mix) for the 4 cones I matched - and I used like two dabs from each. Perfection, has its costs...

But, what the heck were you doing with brake fluid on those LE10A's - some new hydraulic damping? Huh? COME ON, GIVE US YOUR SECRETS!!

[Ian Mackenzie]

Hi Bo,

Got you on those specifications.

At the moment I'm drawing up a new " super baffle " for 4345 clone thanks to your assistance.

It should look cool when I'm finished.

Thanks again for your help.

Cheers

Ian

[Mr. Widget]

Bo, the brake fluid softens the old stiff lans-alloy surrounds.

Earl, I would recommend that you air brush the stain. That way you won't add any more mass than is absolutely necessary. Start with an off white that is a close match and blend it in. If you can find an artist friend to do the work suggest they use designers gouache. It is very opaque and matte so very little would be required.

[boputnam]

"brake fluid softens the old stiff lans-alloy surrounds."

Well, that would save quite a bit of work. Every one I've come across has not only been "stiff", but cracked as well, so replacement was the only route...

[Tom Loizeaux]

The 2405s in my 4333 and 4343 cabinets, when mounted from inside the cabinet using the rubber gasket ring, barely protrud and are basically flush with the front baffel with is 1" thick.

Tom

[Earl K]

Hi All

Thanks for the air-brushing advice Mr Widget.

Bo, heck no, I haven't been holding out on this topic. Most of the chat on the topic "departed" with the implosions of all the previous forums. That's not really such a bad thing, because to successfully mess around with this technique, people must be able to do Fs measurements plus have a lot of patience. I thought you're posting of the pictorial step by step "refoaming a surround" was brilliant - BTW .
This forum does contain a bit of my info on the "brake fluid thing" buried deep within a thread, called 2235 Break in Time .

regards <. Earl K

[GordonW]

Originally posted by Mr. Widget
Bo, the brake fluid softens the old stiff lans-alloy surrounds.

Earl, I would recommend that you air brush the stain. That way you won't add any more mass than is absolutely necessary. Start with an off white that is a close match and blend it in. If you can find an artist friend to do the work suggest they use designers gouache. It is very opaque and matte so very little would be required.

Have you tried plain old pure alcohol (the main solvent in brake fluid)? I've found alcohol to be able to dissolve/soften/de-gunk many of the old surround materials and glues, without screwing up the stuff you want to keep...

Regards,
Gordon.

[boputnam]

Heck, Earl...

I find that in participating on this forum, for the decades I was hefting pro-audio gear for my numerous efforts (and equal number of bands... ) at LIVE sound, while largely ignoring the home gear (or at the least, suffering through store-bought gear...) I learn a great deal from y'all who have done the obverse - spending decades of paying strict attention to all this. Your experiences are vast, and priceless.

I only hope we don't lose this Forum, too. Don? Let us know when finances ar crimping the model. We're always ready...