• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

JBL D-130s & Altec 511b horns...

Redboy

Redboy

a few good watts
So I've had a hankerin' for some horns lately. It came on like a bad case of midnight munchies, and I couldn't shake it. I posted only a few days ago to feel out some initial ideas, and suddenly I'm cobbling together a Frankenspeaker!

A little history...

Found some D-130s in Barzilay cabs last month. Local speaker brewmeister doucanoe chimed in...

doucanoe said:
Here's an idea though, I have a pair of Altec 511b's with 808-8a drivers sitting around. If we could figure out the x-over and l-pad deal, we could try them with the D-130's. I would really like to hear that combo with the D-130's in those cabs. Right down my alley and would make for a great mad scientist experiment.
Click to expand...
Well, RC just left the house. We had a nice cup of java and listened to a few tunes...

And now I've got THIS in my garage... :yikes:

IMG_6217.jpg


IMG_6218.jpg
 
Register to hide this ad
Is this a good idea?!

The idea's in it's fetal stages right now. I don't own an active crossover and I really don't know how to invent a passive from scratch, though I could probably solder one up if someone were to provide a schematic.

At this point I'm not even sure if using the D-130's is a good idea. They don't dig very deep, but some of that could be the cabinet's fault. It's fairly resonant for something that size (about 4.6 cubic feet if my math's right) and is poorly damped.

doucanoe's idea is to tune the cab to 40hz and cross the horns over around 800hz (correct me if I'm wrong, RC).
 
The Eminence 800Hz 2 way XO's from PE work very well. Just add a zobel to even out the impedance of the woofer and an L-pad to match the horn level with that of the LF driver and you'll be 98% there. YMMV, of course.
 
You can get big, wonderful bass out of 4.5 cuft. boxes, but not using D130s.

Those cabinets are very beautiful, and well worth restoring. They need bases, or legs.

It looks like the front baffles are removeable. Is that the case? If so, you can put just about any system in them your budget will allow.

If that's a round hole through in the top corner, the tuning is presently messed up, even for D130s.

The simplest of crossovers will get what you have there running, as macaltec recommends.

http://audioheritage.org/vbulletin/showthread.php?p=156257#post156257
 
Ohh, don't that look tasty!

Cabinet tuning is just a matter of internal volume and correct porting really. You could vary the figure using Box Plot or Win ISD and just see what kind of performance and curve you can expect dependent on TS parameters of your woofers. Not quite that simple but thats about it. Im no expert by any means but by plugging in the figures, you should get better than ballpark anyway.

Passive x-over design is not my thing yet. I took the "easy" route and went active with bi-amping. Gave me the flexibility to experiment with various horn/horn driver combinations and the ability to make adjustments on the fly.

Your cabs seem right at home under the 511B's but still need bracing and fill. You are almost there!

RC
 
Yeah, they do look cool, don't they?! :thmbsp:

Zilch, I do think the baffles are removable from the backside/inside. Suggestions for bases, or legs?

I was trying to check out those Eminence x-overs, but PE seems to be having some problems at the moment.
 
Yes, PE seems to be messed up today.

Get a simple recessed 2x2 frame under them for now, to protect the veneer. You can make sculpted legs easily, or buy appropriate metal ones later.

These might look good (inset, left):

http://www.lansingheritage.org/images/jbl/plans/c35-c39/page2.jpg

See toe kick at the right there, also. At least do that.

JBL 2235H in that size box will make better bass than just about anything. It's also good up to 1kHz for building two-ways (red).

I think that's also the right size for LE14 extended-bass alignment, one of my favorites (black).

How much room is available to mount a horn between the top of the woofer and that piece at the top there?
 

Attachments

  • Barzilay.jpg
    Barzilay.jpg
    33.5 KB · Views: 38
Nate, you should be able to see the fasteners on the perimeter of the front baffle (interior of cabinet) I would think that would be the case with your Barzilays.

As crazy as it appears, maybe your beautiful condition pair of D130's are expendible.

RC
 
doucanoe said:
As crazy as it appears, maybe your beautiful condition pair of D130's are expendible.
Click to expand...
If the boxes were tuned properly as you recommended, they'd be usable to 40 hz, which, depending upon preference, may be good enough.

For extended bass, a different woofer would be required.

Seeing that duct in there, it looks like somebody was trying to get more bass not knowing what they were doing.... :dunno:
 
Zilch said:
If the boxes were tuned properly as you recommended, they'd be useable to 40 hz, which, depending upon preference, may be good enough.

For extended bass, a different woofer would be required.

Seeing that duct in there, it looks like somebody was trying to get more bass not knowing what they were doing.... :dunno:
Click to expand...


I agree, we listened to the D130's in those cabs a couple of weeks ago running "full range" and it seemed that either the box tuning was a little frapped up or the lack of bracing and fill was creating some resonance issues. Listening that way, it was hard to look beyond the lack of HF extension but the lows were still off to my ears. Not terrible but not right if you know what I mean.

2235H eh? Now if you had a pair of those Nate, you really would be set. If I had a pair I would give them to... Nah, I would have to keep them for myself :naughty:

RC
 
doucanoe said:
2235H eh? Now if you had a pair of those Nate, you really would be set.
Click to expand...
"As new" 2235s we make from FUBAR 2225s, of course, but used LE14As are more common and less "dear" than 2235s, and usually just requre refoam....
 
Here I am trying to learn Altec numbers, and you guys are talkin' JBL code! At least, I think that's what's going on...:withstpd:

2235H, huh? Hopefully I'll find a couple in the next pair of big boxes that comes along.
 
I'll throw out the idea of sand filled bases about 3" high. Good foundation for these cabs IMO.

Looking good by the way Nate.
 
Zilch said:
Seeing that duct in there, it looks like somebody was trying to get more bass not knowing what they were doing.... :dunno:
Click to expand...
The duct apparently was part of the Barzilay design - I did some searches and found the same cabs on that auction site. They had the same duct, same damping, everything.
 
Redboy said:
The duct apparently was part of the Barzilay design - I did some searches and found the same cabs on that auction site. They had the same duct, same damping, everything.
Click to expand...
If the hole up top is open through the face, that's the port, and the duct isn't doing anything I can think of. Gordon'd know, probably; he's likely seen these before.

BTW, it was common practice back then not to put damping on the front baffle and one side.

Again, how much vertical room is there above the woofer to sneak a horn in there?
 
Thanks for the warning. I intend to run only tubes on this setup, and the maximum output I've got is about 20 watts per channel with the Pilot.
 
You must log in or register to reply here.
Back
Top Bottom