Help ID 1961 JBL speaker ( D130 / 075 / 2400 crossover )

[heavymod]

I came across this single modified JBL speaker. It looks like they cut out the front baffle and replaced it with a homemade one? Not sure why they made those specific placement choices... any insight into that? I'm also curious what the original speaker model was. Outer dimensions are approx 31.5 x 23.5 x16.25 in.

Haven't tested it out yet - I'm a novice at audio stuff, so don't want to damage anything. I'm in the SouthWest, so stuff get's really dry ... don't want the cones/rubber to crack or anything because I do something stupid! Is there anything I should do to protect the speaker before playing it?

Any insight into how the crossover works on the back? It rotates smoothly in both directions ( I assumed it would "click" between the 1/2/3/4... but it does not ) Is that a volume control? Crossover freq? I linked a few photos on imgur, and embedded some below: http://imgur.com/a/hyKlY

[BMWCCA]

I would have to say the whole thing is home-built. The N2400 crossover is the right one for the 030 system. the N1200 has a stepped control but the N2400 does not.

[heavymod]

I would have to say the whole thing is home-built. The N2400 crossover is the right one for the 030 system. the N1200 has a stepped control but the N2400 does not.

Thanks. What do you mean by stepped controls. Is that a volume controller on the back? ( 1-4 ) ?

The drivers seem like a correct match, right? N2400 + D130 + 075. But your comment makes it seem like there is a problem... I'm not understanding that part.

Do you think the cabinet is just some random cabinet?

[Wagner]

Thanks. What do you mean by stepped controls. Is that a volume controller on the back? ( 1-4 ) ?

The drivers seem like a correct match, right? N2400 + D130 + 075. But your comment makes it seem like there is a problem... I'm not understanding that part.

Do you think the cabinet is just some random cabinet?

Nice score

http://www.lansingheritage.org/html/jbl/jbl.htm

Thomas

[heavymod]

Nice score

http://www.lansingheritage.org/html/jbl/jbl.htm

Thomas

Thanks!

[heavymod]

Nice score

http://www.lansingheritage.org/html/jbl/jbl.htm

Thomas

was going through documents - I didn't realize that JBL had I guess kits? Instructions to create your own enclosure - so maybe that is what this guy was doing. This doesn't follow the plans I found though, and the ports are odd ( multiple drilled holes vs square tube ). Wish I had a second one, I"d be tempted to create my own set of enclosures. Is there any value in keeping the cabinet with the speakers? I might start looking for a replacement cabinet.

Any thoughts?

[Wagner]

was going through documents - I didn't realize that JBL had I guess kits? Instructions to create your own enclosure - so maybe that is what this guy was doing. This doesn't follow the plans I found though, and the ports are odd ( multiple drilled holes vs square tube ). Wish I had a second one, I"d be tempted to create my own set of enclosures. Is there any value in keeping the cabinet with the speakers? I might start looking for a replacement cabinet.

Any thoughts?

Someone bought a cab and loaded in what they had or could afford
Back in the day that's how it was
That "C" designation followed by numbers is for the cabinet, NOT the load
If you look through those old catalogs you'll see how it went - was a building block/upgrade path/system

You will see that for different cabinet types JBL provided the load options as well as a kit for blocking off holes you didn't need or for reducing a 15" cut-out down to 12" in some instances

The cabinets had the "model" designations and the drivers were the "components"

And yes, JBL provided, and sold, numerous plans as well as finished cabinets and systems - it was all about selling drivers to both the home and the "pro" market (and during the age of Heathkits do it yourselfers were appreciated/welcomed too) A FANTASTIC company that covered a LOT of bases well for many years

Someone way back in the day drilled those holes in that baffle because they thought it was a good idea - I can't tell you if it was a good one or not

Regardless, it would be an easy fix to plug them up nicely with some pieces of dowel, sand the baffle smooth and shoot it with some of this, it's fantastic paint:

[heavymod]

Someone bought a cab and loaded in what they had or could afford
Back in the day that's how it was
That "C" designation followed by numbers is for the cabinet, NOT the load
If you look through those old catalogs you'll see how it went - was a building block/upgrade path/system

You will see that for different cabinet types JBL provided the load options as well as a kit for blocking off holes you didn't need or for reducing a 15" cut-out down to 12" in some instances

The cabinets had the "model" designations and the drivers were the "components"

And yes, JBL provided, and sold, numerous plans as well as finished cabinets and systems - it was all about selling drivers to both the home and the "pro" market (and during the age of Heathkits do it yourselfers were appreciated/welcomed too) A FANTASTIC company that covered a LOT of bases well for many years

Someone way back in the day drilled those holes in that baffle because they thought it was a good idea - I can't tell you if it was a good one or not

Regardless, it would be an easy fix to plug them up nicely with some pieces of dowel, sand the baffle smooth and shoot it with some of this, it's fantastic paint:

Thanks that is very helpful. I think it is weird they cut out the old grill cloth to get to the baffle. Anyway to tell which cabinet this is? Does it look like a JBL cab to you?

Is the dial on the back ( 1/2/3/4 ) volume, or crossover freq, or some other adjustment?

If I work on this cabinet, does the baffle come out easily? I'd prefer to redo it, and the grillcloth as well.

[Don C]

Anyway to tell which cabinet this is? Does it look like a JBL cab to you?

Its a homebuilt cabinet. Just about any factory, and certainly JBL, would have the equipment to cut round holes.

[Wagner]

Its a homebuilt cabinet.

I wouldn't bet on that, looks a lot like "factory" to me
Home chopped up a little maybe
A good clear shot of the bottom would let one know for certain

[Wagner]

Thanks that is very helpful. I think it is weird they cut out the old grill cloth to get to the baffle. Anyway to tell which cabinet this is? Does it look like a JBL cab to you?

Is the dial on the back ( 1/2/3/4 ) volume, or crossover freq, or some other adjustment?

If I work on this cabinet, does the baffle come out easily? I'd prefer to redo it, and the grillcloth as well.

You have the box there in front of you - how is it (the baffle) attached? Screws or glue or both?

It is a losing game to spend a great deal of time trying to figure out or understand what and why people do some of the things they do

Take a good photo of the bottom, and back of the box - in which I can see the bottom corners well and the network you keep asking about and maybe I can give you an/some answer(s)

[heavymod]

You have the box there in front of you - how is it (the baffle) attached? Screws or glue or both?

It is a losing game to spend a great deal of time trying to figure out or understand what and why people do some of the things they do

Take a good photo of the bottom, and back of the box - in which I can see the bottom corners well and the network you keep asking about and maybe I can give you an/some answer(s)

Ha, yeah fair enough. But I figured I'd ask, maybe someone would be "Oh actually drilling holes like that creates multiple tiny ports that ... blah blah blah..."

There are more photos here, including a full shot of the bottom, and the cross over: http://imgur.com/a/hyKlY

Back with crossover: http://i.imgur.com/puF3Q83.jpg

Bottom corner ( note some overlap of front face.. it extends below the bottom about 1/4 inch.. ) http://i.imgur.com/eHH5xpN.jpg

Bottom ( with markings for feet ) : http://i.imgur.com/OzNhQC3.jpg



I'll open it up and take another look at how the baffle is attached this evening when I get home! Part of the reason I'm so curious about the cabinet is I would like to try and find a matching one. So would be great if it is possible to ID it at all. However, the dimensions of my cabinet don't seem to match what I found in a ( quick ) search of the catalogs.

Thanks for all the help and replies!

[Wagner]

Ha, yeah fair enough. But I figured I'd ask, maybe someone would be "Oh actually drilling holes like that creates multiple tiny ports that ... blah blah blah..."

There are more photos here, including a full shot of the bottom, and the cross over: http://imgur.com/a/hyKlY

Back with crossover: http://i.imgur.com/puF3Q83.jpg

Bottom corner ( note some overlap of front face.. it extends below the bottom about 1/4 inch.. ) http://i.imgur.com/eHH5xpN.jpg

Bottom ( with markings for feet ) : http://i.imgur.com/OzNhQC3.jpg



I'll open it up and take another look at how the baffle is attached this evening when I get home! Part of the reason I'm so curious about the cabinet is I would like to try and find a matching one. So would be great if it is possible to ID it at all. However, the dimensions of my cabinet don't seem to match what I found in a ( quick ) search of the catalogs.

Thanks for all the help and replies!

Any of those holes in the bottom have a "T" nut in them? If not then it's most likely a home built as Don C suggested, BUT still not 100% certain with what I have so far (but based on a few visual ques I am starting to agree that it's a wholly DIY job) Not necessarily a bad thing, an enormous share of the homemades were just clones of "real" JBLs

As for those holes? Discussed here:
http://www.audioheritage.org/vbullet...Way-JBL-C-38-s

Those holes are an attempt at a reflex box of sorts OR maybe looking for an infinite baffle sort of effect............like I said, I don't know what the person was thinking or hoping to accomplish specifically when they drilled them, I wasn't there
We can speculate it being one of those two things I have suggested however.............but WHO CARES? It is definitely NOT a JBL design/technique, we know that much for certain

As for identifying your box you NEED TO TAKE YOUR MEASUREMENTS and using the catalogs here at the library match them up with the appropriate enclosure model - EVERY box listing shown in that catalog provides dimensions (several catalogs actually)
I do see that you wrote that you did a "quick" search - well, double check it and if they don't match then you will definitely have your answer

A forgive me, I am starting to confuse this thread and the one I referred you to above (I keep feeling like Deja Vu)...............like I'm repeating myself

Did that box have any sort of feet or legs on it?

Thomas

[heavymod]

Any of those holes in the bottom have a "T" nut in them? If not then it's most likely a home built as Don C suggested, BUT still not 100% certain with what I have so far (but based on a few visual ques I am starting to agree that it's a wholly DIY job) Not necessarily a bad thing, an enormous share of the homemades were just clones of "real" JBLs

As for those holes? Discussed here:
http://www.audioheritage.org/vbullet...Way-JBL-C-38-s

Those holes are an attempt at a reflex box of sorts OR maybe looking for an infinite baffle sort of effect............like I said, I don't know what the person was thinking or hoping to accomplish specifically when they drilled them, I wasn't there
We can speculate it being one of those two things I have suggested however.............but WHO CARES? It is definitely NOT a JBL design/technique, we know that much for certain

As for identifying your box you NEED TO TAKE YOUR MEASUREMENTS and using the catalogs here at the library match them up with the appropriate enclosure model - EVERY box listing shown in that catalog provides dimensions (several catalogs actually)
I do see that you wrote that you did a "quick" search - well, double check it and if they don't match then you will definitely have your answer

A forgive me, I am starting to confuse this thread and the one I referred you to above (I keep feeling like Deja Vu)...............like I'm repeating myself

Did that box have any sort of feet or legs on it?

Thomas

No feet / legs, just the drilled holes I photo'd. No T-Nuts. I didn't see anything in the catalogs that matched the dimensions, so I'm assuming it was a re-purposed cabinet. Which makes it easier for me I guess - easier to start from scratch and find matching cabinets.

re: the crossover - what does the dial on the back do?

Thanks for all your help!

[Wagner]

No feet / legs, just the drilled holes I photo'd. No T-Nuts. I didn't see anything in the catalogs that matched the dimensions, so I'm assuming it was a re-purposed cabinet. Which makes it easier for me I guess - easier to start from scratch and find matching cabinets.

re: the crossover - what does the dial on the back do?

Thanks for all your help!

That, or built from scratch

The control on the back is a HF attenuator or "L-pad" - it allows you to adjust the tweeter's output levels depending on your tastes, the material you are playing, or your room's acoustics

Good photos in this old thread:
http://www.audioheritage.org/vbullet...N2400-Revealed