DIY 4320

[Woofer]

Although a JBL 4320 project is discussed elsewhere on these forums,
http://audioheritage.csdco.com/vbulletin/showthread.php?t=9796
I can't find the internal dimensions mentioned (especially porting and duct length details) anywhere in the thread, so could some kind soul post the internal and external dimensions of the JBL 4320/5 please?

Cheers all,
Woofer.

[hjames]

Although a JBL 4320 project is discussed elsewhere on these forums,
http://audioheritage.csdco.com/vbulletin/showthread.php?t=9796
I can't find the internal dimensions mentioned (especially porting and duct length details) anywhere in the thread, so could some kind soul post the internal and external dimensions of the JBL 4320/5 please?

Cheers all,
Woofer.
Sorry for the delay - I've blown out my back recently and am not likely to be taking those puppies down off the shelf anytime soon! I'd love to help you out tho, so with any luck over the coming weekend I'll get a tape measure and measure port length and ID for ya ... I'll post it in the main thread to be consistant with that data ...

If I can, I'll measure box outside dimensions ... from all I can see, they are just basic JBL 4505 enclosures ...
http://audioheritage.csdco.com/vbulletin/showthread.php?t=3441&highlight=4505
which is pretty much the same as what the 4333 is built with (if that helps).

But, as I said - I'll try to at least get you port ID and length specs soon ...

[Woofer]

Sorry for the delay - I've blown out my back recently and am not likely to be takin' them puppies down off the shelf anytime soon. I'd love to help you out tho, so with any luck over the coming weekend I'll get a tape measure and measure port length and ID for ya ... I'll post it in the main thread to be consistant with that data ...

If I can, I'll measure box outside dimensions ... from all I can see, they are just basic JBL 4505 enclosures ...
http://audioheritage.csdco.com/vbulletin/showthread.php?t=3441&highlight=4505
which is pretty much the same as what the 4333 is built with (if that helps).

But, as I said - I'll try to at least get you port ID and length specs soon ...

You are so kind. I thank you very much.
... and thanks heaps for that link.
I had no idea they were (almost) the same thing.
There's no hurry for that info I asked for, so please take your time.
Mine is a long term project, so there's certainly no urgency.

All the best,
Woofer.

[Woofer]

hjames I've managed to come up with a possible solution using some very antiquated Mac s/w called MacSpeakerz, and using approximate box internal dimensions, (which you can see from the pic below), I think I may have come up with a workable solution.
Although, no matter how I try, I can't seem to get the box tuning any lower than about 40Hz at -3dB, (using two 4 inch ports at 3.6" in length), which would be about right I s'pose for the 2215. (but pretty flat otherwise all the way up to at least 1K.)
I'm curious to know how far off I am now, so when you get around to it, I'll be very interested in your measurements.
.... but, like I said, there's definitely no hurry.
I was just bored and on a roll.

http://img225.imageshack.us/img225/5230/2215plotmy5.jpg

[Woofer]

It's been a while, so I'm making a renewed plea for help regarding the 4320 box with the 2215 speaker, especially the correct dual port specs. :o:
(please see my first post)
I can only guess what they might be, but I would definitely prefer to hear from an OWNER that may have the 'proper' JBL measurements handy.

Cheers all.

[hjames]

Although a JBL 4320 project is discussed elsewhere on these forums,
http://audioheritage.csdco.com/vbulletin/showthread.php?t=9796
I can't find the internal dimensions mentioned (especially porting and duct length details) anywhere in the thread, so could some kind soul post the internal and external dimensions of the JBL 4320/5 please?

Cheers all,
Woofer.

I took a tape measure -
Box dimensions - 30" tall x 23 3/4 wide x 20 1/4 deep
The top and bottom "lip" extends 3 1/2 from the baffleboard
Measured through one port from back panel "inside face" to front face of baffleboard is 15 1/2"

Mine has dual ports - 4 inch ID, 7 /1/4 deep

Its still up on the shelf, can't lift her down for teardown and more inner dimensions, but what else did you want to know?

Before I started with the upgrades, they were 2 way 4320s -
4502 Enclosure
2215 15" woofer
2420 MF driver - 2307 (short) horn - 2308 lens
3110 Crossover

[Woofer]

I took a tape measure -
Box dimensions - 30" tall x 24 3/4 wide x 20 1/4 deep
The top and bottom "lip" extends 3 1/2 from the baffleboard
Measured through one port from back panel "inside face" to front face of baffleboard is 15 1/2"

Mine has dual ports - 4 inch ID, 7 /1/4 deep

Its still up on the shelf, can't lift her down for teardown and more inner dimensions, but what else did you want to know?

Before I started with the upgrades, they were 2 way 4320s -
4502 Enclosure
2215 15" woofer
2420 MF driver
3110 Crossover

Thankyou thankyou thankyou....

You have covered just about everything I needed to know, (especially the port specs.)
I'm pretty sure the thickness of the sides/top/bottom/baffle and back are covered elsewhere, so I'll have another look shortly.

I am truly grateful. :applaud:

[hjames]

Thankyou thankyou thankyou....

You have covered just about everything I needed to know, (especially the port specs.)
I'm pretty sure the thickness of the sides/top/bottom/baffle and back are covered elsewhere, so I'll have another look shortly.

I am truly grateful. :applaud:

I measure the exposed lip thickness as 3/4 inch -
would that be 5/8 plywood with veneer on two sides? I know when I had it apart before I was surprised to see it was plywood - maybe the particle board boxes came later?

According to the Ed May history page it came out in '68 (http://www.audioheritage.org/html/people/may.htm):

In 1968, Capitol Records had approached JBL for an update to the D50SMS7. This would become the renowned 4320. The power handling on the D50 was restricted by the low 500hz cross-over point. Integration between the drivers was also compromised by this cross-over. Ed designed the 4320 with a new 800hz cross-over that significantly increased power handling while providing both flat axial and power response. Where the D50 gave JBL a foot in the door in the studio market, the 4320 made JBL an established presence. Shortly after its introduction, the 4320 became Capitol's standard main monitor. For the first time there were also significant sales to record companies beyond Capitol.

[Woofer]

I measure the exposed lip thickness as 3/4 inch -
would that be 5/8 plywood with veneer on two sides? I know when I had it apart before I was surprised to see it was plywood - maybe the particle board boxes came later?

According to the Ed May history page it came out in '68 (http://www.audioheritage.org/html/people/may.htm):

In 1968, Capitol Records had approached JBL for an update to the D50SMS7. This would become the renowned 4320. The power handling on the D50 was restricted by the low 500hz cross-over point. Integration between the drivers was also compromised by this cross-over. Ed designed the 4320 with a new 800hz cross-over that significantly increased power handling while providing both flat axial and power response. Where the D50 gave JBL a foot in the door in the studio market, the 4320 made JBL an established presence. Shortly after its introduction, the 4320 became Capitol's standard main monitor. For the first time there were also significant sales to record companies beyond Capitol.


That raises some interesting issues.
Which Horn did they originally use to accomplish such a low crossover point?
I was under the impression that the Horn/lens arrangement was based around the H91/2307 Horn which from what I've gathered so far is recommended at 1k2 and useable to 800Hz.
Does this mean that it will go down to 500Hz on a 2420 comfortably?
I know I cross mine over at 500Hz sometimes, and I feel it makes a remarkable difference, but it usually is at low level SPL. Sooooo much more vocal prescence. Maybe a little too much at times, so I just roll back the x-over point back up to the 1k area. (the advantages of bi-amping and a variable x-over eg: Crown VFX-2). I'm not that keen on what comes off the cone with 2215's around this region, but that could be totally due to the boxes they're currently in.
Until I get the proper boxes built, I'm having to persevere with my 2215's mounted in a pair of 4530 J-Bins but they just don't quite sound right. (they do from the next appartment though, according to my neighbour!) I need something much more short throw for bottom end, and I'm sick to death of having a whole pile of assorted drivers sitting loosely on top of the boxes. It's time to tidy up.
Oh to be living in the USA. I've seen so many empty original boxes go on eBay for next to nothing. A little TLC is all it'd take.

Anyway, I'm rambling again, :blah: so I'll say thanks again Heather.

George. :bouncy:

[Woofer]

.... and upon your clue, (D50SMS7) therein lies the answers.

http://www.lansingheritage.org/html/jbl/specs/pro-speakers/1967-d50sm7.htm

[Zilch]

I took a tape measure -
Box dimensions - 30" tall x 24 3/4 wide x 20 1/4 deep
The top and bottom "lip" extends 3 1/2 from the baffleboard
Measured through one port from back panel "inside face" to front face of baffleboard is 15 1/2"

Mine has dual ports - 4 inch ID, 7 /1/4 deepInterestingly, my 4505WX 4325s (2216) are all the same dimensions, except 1" narrower. Also dual ports, same size.

When removing the 2420s/2307s from them a couple of weeks ago, I remember asking myself if the longer horns would fit. The answer was "No way, I don't think." The net inside depth is 14-3/4", the baffle being 11-ply 3/4" stock. What depth is required for 2308/H92 + 2420/LE85?


That raises some interesting issues.
Which Horn did they originally use to accomplish such a low crossover point?

I was under the impression that the Horn/lens arrangement was based around the H91/2307 Horn which from what I've gathered so far is recommended at 1k2 and useable to 800Hz.

Does this mean that it will go down to 500Hz on a 2420 comfortably?No.

That's the reason S7s sound "Horny."

[Woofer]

Interestingly, my 4505WX 4325s (2216) are all the same dimensions, except 1" narrower. Also dual ports, same size.

When removing the 2420s/2307s from them a couple of weeks ago, I remember asking myself if the longer horns would fit. The answer was "No way, I don't think." The net inside depth is 14-3/4", the baffle being 11-ply 3/4" stock. What depth is required for 2308/H92 + 2420/LE85?

No.

That's the reason S7s sound "Horny."

Understandably so when dealing with a front load box, but I as yet have the luxury of experiencing that due to the fact that I've got J-bins, and the mids are very forward off the 15" and sound downright ugly sometimes, so I guess I'm not noticing the 'horn' effect as much as I would with a 4520 type box.
Interesting to note your boxes are narrower than the ones previously mentioned though.
As far as the H92 goes, I think I read somewhere that they're from the L300/4333, so how deep are they?? I thought a 4333 was 'almost' the same as the 4520, but I guess not. I'm getting lost quickly..... and there's just sooooo much info, and only one lifetime to read it all.
(BTW, there's a pair of H92's on eBay if anyone's interested.)

[hjames]

Interestingly, my 4505WX 4325s (2216) are all the same dimensions, except 1" narrower. Also dual ports, same size."


Interestingly enough - thats the size mine measure this morning!

Box dimensions - 30" tall x 23 3/4 wide x 20 1/4 deep

Must have fooled me, laying on their sides up high like that ... sigh ...

Sorry!

[Zilch]

Thank you for rechecking, Heather.

So, 4502 and 4505 are the same size box with same size and number of ports. Perhaps someone here knows what it all means/meant. ;)

I'll load some 2235H's in 'em and see how they measure. I'm betting very similar to L200s.

Some new parts coming from JBL to make them into killer two-ways.

[That's my "thing" here, you know.... :p ]

[hjames]

Thank you for rechecking, Heather.

So, 4502 and 4505 are the same size box with same size and number of ports. Perhaps someone here knows what it all means/meant. ;)

I'll load some 2235H's in 'em and see how they measure. I'm betting very similar to L200s.

Some new parts coming from JBL to make them into killer two-ways.

[That's my "thing" here, you know.... :p ]

Its a GOOD thing that you have, working with the boxes!

Somewhere down the line (next year perhaps) I'll look for a set of 2235s to replace my 2215s with - but other than paying the shop for my "new" amp's repairs today, (and some crossover updates) I think I'm done buying big parts for the year.

[Woofer]

OK, just to confuse the issue, I now have two different measurements for the 'net' 'front to back' dimension (depth).
One of 14 3/4" (as stated by Zilch) and the other of 15 1/4"
(as worked out from Heather's specs)

If the overall depth is 20 1/4" and the front overhang is 3 1/2" and the back and baffle thickness total 1 1/2" (3/4" each) then therefore the inside measurement should be:
20 1/4" - 3 1/2" - 1 1/2" = 15 1/4", right?

Yet Zilch, you state that particular measurement is 14 3/4".
How is that extra 1/2" accounted for?

:blink:

[Zilch]

Heather and I both provided the same dimension, from the inside of the rear baffle to the outside of the front baffle, which is 3/4" thick. 15.5 minus 0.75 gives 14.75" inside depth of the cabinet.

The missing 1/2" from the exterior dimensions is the the inset of the rear baffle in back. It's not flush with the sides, top, and bottom....

[Woofer]

Heather and I both provided the same dimension, from the inside of the rear baffle to the outside of the front baffle, which is 3/4" thick. 15.5 minus 0.75 gives 14.75" inside depth of the cabinet.

The missing 1/2" from the exterior dimensions is the the inset of the rear baffle in back. It's not flush with the sides, top, and bottom....

Ahhhhh.....
Got it.
I didn't know about the back inset.
Cheers heaps for that Zilch. :D

[Zilch]

What're ya gonna put in them homebrew 4320s, Woofer? ;)

[Woofer]

What're ya gonna put in them homebrew 4320s, Woofer? ;)

I have a pair of 2215A's, a pair of 2470's but with 2421 8 ohm diaphragms, and a pair of 2307 Horns, (but I've misplaced the lenses and I'm still looking for them,) and a pair of 077 Slots, using a 3105 crossover for the slots and a Crown VFX-2 for bi-amping from Lo to Mids. (I'm not really happy with the 3105 as I think it crosses at 7K, and I think that's too low considering the 2470/21's will go up to 20K anyway.)
To power up with I have a Phase Linear 700 Claire Bros. model but I'm also trying to find a PL 400 II for the Horns and Slots to replace the Crown D75 I'm using on them at the moment.
It's taken a while to find everything.
All I have left to do now is build the boxes.

[Zilch]

Low pass in 3105 wants 16 Ohms, I believe.

I just did an 8.5 kHz highpass for the slot. You should be able to extract it and rework the lowpass (right of LPad1) for 8 ohms:

http://audioheritage.org/vbulletin/showthread.php?p=130246#post130246

[Woofer]

Low pass in 3105 wants 16 Ohms, I believe.

I just did an 8.5 kHz highpass for the slot. You should be able to extract it and rework the lowpass (right of LPad1) for 8 ohms:

http://audioheritage.org/vbulletin/showthread.php?p=130246#post130246

What, just change R6 to something like 10 ohms, or will the choke and capicitor have to be changed also?
This is way out of my league, so forgive me for asking.
I'm an old school sound guy that knows where to kick 'em to restart 'em, but I'm afraid my technological understanding is a tad wanting.

[Zilch]

Leave the 20 Ohms. Halve the choke and double the capacitor.

If I get a chance later this week, I'll try that for you, as I still have the breadboard here....

[Woofer]

Leave the 20 Ohms. Halve the choke and double the capacitor.

If I get a chance later this week, I'll try that for you, as I still have the breadboard here....

I knew I'd get it round the wrong way...
Thanks for clarifying, and thanks for the offer. Don't go to too much trouble though. If you can, great, if you can't, it's OK too. I'm open to experimentation at the moment.
Alternately, I might seriously reconsider just running another active crossover, and power amp for the 077's
Furman 24dB crossovers are quite good and they seem to be cheap and in abundance 'downunder' at the moment.
They feature Phase Reversal, Limiting on each output, Compression driver/horn EQ switches on high outputs and a Slope switch gives Linkwitz-Riley/Butterworth choices. (for what it's worth)
I'll just have to remember to add some blocking capacitors to the mid and hi drivers just in case any of the amps go DC.

UPDATE:

I've just pulled the 8 ohm diaphragms out and replaced them with 16 ohm aftermarket ones (my original ones before I got the new JBL replacements), and the problem is solved for now. (certainly doesn't sound any worse)

[Zilch]

I confirm LE85 on 2312 (H92) is 14-5/8" long (what Toddalin calculated, exactly,) and fits in 4505WX (what Chas said.)

There's only 1/8" to spare, so you have to bolt the driver on with the horn in place; don't bolt the horn to the baffle until after that's done, so it can rotate to make attaching the driver easy: