4320 Project

I worked in campus radio at USC (So. Carolina) in the early 70s and got spoiled by the sound of the JBL 4310 Studio Monitors. After school, in 1976 I bought my first JBLs - a set of L36 Decades (still have them and love 'em).
After finding the heritage site last year I decided to upgrade my system and started looking for a set of L300s (or even L200s) I could upgrade, but the eBay prices quickly went beyond what I could justify for a set of speakers.

Mid February I saw a set of "JBL 4505" speakers on eBay. I checked the site and with some helpful folks here I found they were actually 4320 Control Monitors - a 2 way system for recording studios from the early 70s. http://www.lansingheritage.org/html/.../1972-4320.htm
They were big boxes and required local pickup ... so after a brief delay for a snowy weekend, we drove to Philly and brought them back to Virginia.

I found a pair of 2405 drivers with diaphrams to install, again, on ebay, so they were bought and delivered a week later. I'm not a sound engineer, but I do have a technical background and know how to solder. I'm sure they weren't JBL diaphrams, but I could install the furnished diaphrams and if they didn't work right, I could have JBL techs put factory diaphrams in later.

I did a search here and found detailed directions on replacing diaphrams -
http://audioheritage.org/vbulletin/showthread.php?t=700&highlight=2405+diaphram

Anyway - here are a few pictures showing the stages of rebuilding the drivers, cleaning the gap with a piece of clear plastic (cut from the diaphram packaging)
and the final image with dated stickers on the back.

Once they were done I mounted them in the predrilled holes to the left of the horn outlet on the baffleboard, but I once I have the crossover sorted out I'd like to mount them above the horn.

I followed a tip from Zilch and built a pair of 3106 crossovers to tie to the high output of the exisiting crossovers in the box, but I had almost no output on the 2405 slots - tho they worked fine when substituted for some tweeters in another speaker system in the guest room.
I have minimal test gear these days - so I checked some crossovers for sale on ebay and found a pair for JBL L166 - the low cross was at 1000hz - the high cross at 6500 is lower than the 10k I'd like to use, but it allowed me to have all the drivers working until I can redo or replace the MF and HF legs of the crossover.

Nice project. Thanks for sharing the in-progress pics! -grumpy

Hi, Heather, and thanks for posting pics of your project!

If you haven't come across it yet, there's a chain of threads over in DIY for a potential crossover incorporating the 3106, still a work in progress, beginning here:

http://audioheritage.org/vbulletin/s...ead.php?t=8507

For the bottom line, you can also jump to the latest thread here:

http://audioheritage.org/vbulletin/s...ead.php?t=9221

Once work on the basic crossover is complete, a 10 kHz version for 077/2405 seems a logical next step....

[MORE pics, please. Yup, yup!]

Quote:

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Originally Posted by hjames

I followed a tip from Zilch and built a pair of 3106 crossovers to tie to the high output of the exisiting crossovers in the box, but I had almost no output on the 2405 slots....

I have minimal test gear these days....

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If you'd like me to check out your DIY 3106's with 2405's, PM me for the address to send 'em. :thmbsup:

I took my 2405's downstairs and substituted them for the tweeters in a pair of Optimus 3 ways and they worked fine - so I know the slot-tweeters work fine. The 2420 horns and 2215 woofs had worked fine when I used the systems in their original 2 way config for the first weeks, so I figure thats all fine.

The 3106 crossovers I built I had connect to the hi output of the original 3110 crossovers that came with the system didn't seem to work, and it was consistant no matter which one I put on either speaker - so I tried something new. I'm running the speakers in conventional mode with a standard 110w/ch JVC receiver, no bi or tri-amping at the moment ...

I bought a pair of L166 (3way) crossovers off ebay ... the low cross is at 1k, the high cross at 6k (lower than I want, but its a test), and dropped them as the only network in the boxes. The speakers worked fine using them, but now I know what folks mean about harshness using the slots at the lower end of their range - I think I prefer feeding more of the mids through the horns.
I dropped the 3110s back into the box, and fed the high output of those into the L166 networks. I dropped the lowpass (woofer leg) off the L166, and just used the mid and high output of them ... its closer, but I think I need to rework them and get the high cross up near 10k.

I can gut them and use the precision resisters and the 4 JBL style Lpads to build better networks - once I learn what caps and chokes to use for the mid and high legs of the new 3way ... but I have to find time for that ...

I got the JBL cloth from Zilch and bought a pile of pine lumber to build the griills - fortunately our cats don't seem to have cone destroyer tendencies - but we spent this weekend clearing the garden for spring plantings - and hoping we don't get a final snow before winter formally ends. Of course anything is possible in the DC area ... sigh ...
Hopefully I'll get back to the crossover work soon ...

Hello hjames, can you post a picture of the 2405 diaphrams front and back. They look like aftermarket by the one picture. Hard to tell. If they
are aftermarket ones the impedance will most likely be different than stock. A impedance curve would be needed to properly design the new circuit for this.

Quote:

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Originally Posted by jbl4ever

Hello hjames, can you post a picture of the 2405 diaphrams front and back. They look like aftermarket by the one picture. Hard to tell. If they are aftermarket ones the impedance will most likely be different than stock. A impedance curve would be needed to properly design the new circuit for this.

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Not easily - I'd have to pull the woofers to gain access to the drivers, unmount the 2405s, then tear down a working driver.

In truth, I'd rather build the crossovers as if they were the right (JBL) diaphrams - once money is a bit less dear I may send the 2405s out for JBL pro rebuilds anyway, and if I build networks specifically for the aftermarket parts, I'd just have to redo the networks when I change.

I got the 2405s on ebay - the deal was they needed diaphrams installed and a new pair of diaphrams were provided to install. Knowing that any set I bought on eBay have worn or tired diaphrams anyway, they were cheaper than most others pairs offered. From the price of JBL diaphrams, (provided free with the 2405s) I'll assume they are aftermarket.
The diaphrams were sealed in clear plastic trays numbered DWT044S-8.


3110 Crossover LF out to 2215 woof, MF out to L166 Crossover
L166 Crossover LF leg (choke) removed - MF & HF only used
2215 15" woofer
2420 MF driver
2405 HF driver

http://audioheritage.org/vbulletin/s...ead.php?t=3555

Why are we talkin' about this here?

Because Heather asked, is why! :)

I've got a quick question. I've seen the reference to Charge Coupled crossover networks quite a few times in these forums - this is something you do for bi-amped systems right? I mean, you are doing this fancy crossover at a 1v P-P preamp output signal level, correct?
The crossover pictured on the perfboard at http://audioheritage.org/vbulletin/s...1&postcount=28 doesn't look beefy enough for the 200+ wpc power levels you folks run these speakers at ...
I ask because I want to build crossovers for the L300 equivs I am building from my 4320 speakers (2215, 2420, 2405) - and I want to be sure I'm using the right specs to do so.
Thanks for the info!

Quote:

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Originally Posted by hjames

I've got a quick question. I've seen the reference to Charge Coupled crossover networks quite a few times in these forums - this is something you do for bi-amped systems right?

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Nope.

The charge coupled crossovers are standard passive networks being powered by your amplifier. The charge coupling means that they have a DC offset voltage that is reported to lower some forms of distortion caused by the capacitors. I have no personal experience with them, but the people who have tried them really do rave about them.


Widget

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

After reading a number of threads here, I've also followed Giskard's design
trick and put the Lpad and load resistors for the MF HF legs on an external board and mounted that on the back of the baffleboard. I even created a "foilcal" lookalike in photoshop, based on the 4333A foilcal that spirou38 offered here a while back. see - http://audioheritage.org/vbulletin/s...ead.php?t=9544

I bought a cheap Ryobi tablesaw ($99 - Home Despot) that I can clamp into my Shopmate and I've cut down some lumber to build grills with ... got some Zilch cloth to cover the grills with, and a pair of metal JBL Logo badges to slip discreetly into the corner of the grill. I don't have a shed/garage so I just need some less cold weekend time to set up the saw outside and notch the ends of the boards so I can clamp/glue them together. More pictures later ...

I'm hoping to get all this completed by mid-April ... and get the speakers off the floor so I can have my TV room back.

One thing that will change the sound vs a 4333/L300 is the use of your tighter 2215's vs the deeper extension/longer throw 136A/2231A's.

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Originally Posted by remusr

One thing that will change the sound vs a 4333/L300 is the use of your tighter 2215's vs the deeper extension/longer throw 136A/2231A's.

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Ok - should I gather that tightness is not a good thing? Should I just bite the bullet and start looking for a pair of the newer speakers. At the moment, its an all alnico system (for whatever thats worth), but my plan to update the crossovers should indicate I'm willing to do updates to improve the sound.

I would toss into the ring that tightness can be a good thing. If using a 2215 in a box
that's tuned properly, you might like it just fine. -grumpy

"measure then cut"

I have been told some prefer the 2215A/LE15A's to the (also Alnico) 136A/2231A or the newer ferrite 136H/2231H and 2235H. I have tried LE15A's in my L300's and did not like them as much as the 136A's for the lower bass & vocals. Tuning can overcome the bass issue somewhat - I think the 2215A/LE15A's work better in a larger box but have shorter excursion & lower power limits (shorter voice coil?). The 2235H may have better midbass/vocals than the 136A/2231A and can handle more power yet. Expect to pay $150ish each for EBay 136/2231/2235's...and then probably have to refoam them for another $75. My experience anyhows. NRT usually has a stock of woofs!
- Roy

Quote:

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Originally Posted by 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

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I can certainly vouch for this network, it works just fine over here. BTW, I think there was a typo in the schematic, one of the resistors was labeled 40 Watts, I can't recall what I am using - I can check if you want. Maybe Giskard could chime in - but I think 40 W is overkill.

Initially I used Solens, now they are Hovland (except in the low pass portion) in my non-CC version. Expensive, but well worth it to me.

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.

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.:)

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 ...

Nice job Heather!!:D

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

Beautiful!

Gotta LOVE that blue.... ;)

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

Quote:

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Originally Posted by 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

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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!

Congratulations! Well done. :applaud:

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

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?

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

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?

Quote:

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Originally Posted by Zilch

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

Quote:

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Originally Posted by 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?

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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....

Quote:

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Originally Posted by hjames

. . . .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. . . . .

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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

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Originally Posted by speakerdave

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

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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.:banghead:

I agree with Zilch on the 2215's vs 2235's. 2235's will have so much more bottom than the 2215's that you'll think you have 4 speakers. Also, 2231/2235 is the woofer that the 3133x is designed to work with. :bouncy:

Quote:

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Originally Posted by 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?

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Regardless of the 2235/2215A debate, the 2215A is quite repairable and is essentially an 8 ohm impedance version of the venerable LE15A (The LE15A is a 10-12 ohm driver whether it is labeled 8 or 16).

The the 2215 has different sound than the 2235, but you may prefer it to the 2235... the 2235 definitely has deeper bass.

Definitely stay away from the 2220 as it is really only a high efficiency design that is best in PA applications... it can be used to great effect in a home environment with a lot of coaxing and additional bass drivers or horn loading.


Widget

Quote:

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Originally Posted by speakerdave

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.
David

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Maybe sometime later I can pull the left cabinet down off the shelves, bore an asymetrical mounting hole for the slot and move it to the other side of the horn outlet (tho I s'pose I'll have to move the Lpads in that box to do so ...). Meanwhile, I have been able to rotate the 2405 Slots 90 degrees, and I made some shims to allow me to rotate the lenses for the horns 90 degrees, and stand proud of the woofer.

Quote:

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Originally Posted by norealtalent

I agree with Zilch on the 2215's vs 2235's. 2235's will have so much more bottom than the 2215's that you'll think you have 4 speakers. Also, 2231/2235 is the woofer that the 3133x is designed to work with. :bouncy:

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I'll have to keep my eyes open for a pair of them - thanks to everyone who's helped me get this far! ..

I've been reading everyone's comments about 2215A's and 2420's and 4320 Monitors and I just can't beieve the wealth of information available here.
Some of you guys really are so 'over the top' impressive to say the least.
I have a very old pair of 2215A's which I've recently re-foamed and I just love them to death. Granted they're mounted in a pair of 4530 'Scoop/J Bins', powered by a Phase Linear Claire Bros. 700, so there's definitely no shortage of bass there. (Just ask my neighbours). To top them off, I run a pair of vintage 1217-1290 Horns (Potato-Mashers/Tea-strainers/Perforated Plates: call 'em what you will), fitted with a pair of 24??. Actually I think they're JBL 2420 with JBL 2470 backs but fitted with aftermarket 16 ohm diaphragms and powered by a Crown D75. (howzat for a Frankenstein version of a JBL Driver - huh? I figure the 2420 and 2470 are the same magnet wise 'cept for the foil badges. Please correct me if I'm wrong.) Although for now, they sound great, but I'm wondering how much better they'd sound with the ever so much dearer correct JBL replacements. (which are just way too expensive here in Australia, that one can only dream of getting original ones). I've been using a Crown VFX2 Active Crossover set at anything between 800Hz and 1K2, depending on what I'm listening to, but was also wondering if I'd be better off using the original 3110 Passive crossover? As well as all the prementioned stuff, I do have a pair of old 077 Slots but alas, I can't hook them up as yet due to my 3105 Crossovers being in desperate need of replacement L-pads. If someone has a spare pair of L-Pads then please let me know, as the cost of replacements here from a local JBL distributor, would be enough to pay for my next months rent! (The disadvantages of living and sourcing stuff in Australia is almost enough to drive one to suicide.)
All in all, being an old Rock'n'Roll sound guy, it's pretty exciting listening to, but my listening habits are changing, and I think it's time to change boxes for something along the lines of a 4320 or a 4333 type of box. I've found the plans for the 4333A onsite, but I'm afraid my 2215A's may not be suitable for those. I've looked but I'm unable to find plans for the 4320 box, and if they do exist here, could someone be kind enough to point me in the right direction please? I have a rough idea of the size of the box, but I can't find the dimensions for the TWO ports as opposed to the single one in the 4333. At least in the meantime, until I get the rest together, I do have a pair of 4301BE's which are really such an underated little speaker. Honestly, everytime I listen to them, I just can't stop being amazed. Pure joy.
Sorry for being so long winded, but hopefully someone is still monitoring this thread and can help me out.
If I've sinned by posting in the wrong thread, please don't be too unkind.
Cheers all,
Woofer.

I've pulled a few quotes from a thread on hissing tweaters as I partially sidetracked it, and thought the biAmping 4320s thread should go here ...

Quote:

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Originally Posted by hjames

So If I was to biAmp or triAamp my 4320s, I gather I could take the existing output of my preamp, run it into a crossover (folks told me it had to be an active crossover, not the "speaker crossovers" I built and installed within the speaker cabs) then feed their output to discreet amps for each driver? :D

So the D75 (est 40w/ch) would be a good approach to feed the slots?
What about the 2420 Horns - should I find a D-150
What about the 2215s - something like a DC-300?

I'm just feeding the whole thing currently with a 110/ch JVC high end A/V receiver now, but I believe I can pull the front channel preamp outs to feed external gear.

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Quote:

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Originally Posted by scott fitlin

Yep, that combination in that order will work.

As Widget stated, you really need a dedicated active electronic crossover.

There is a good place for GOOD electronic crossovers, available in kit form, reasonable prices, to very expensive prices. I recommend an XM-44, youll have to decide your crossover points, and is available with 6,12,18,24 or 48 db slopes.
www.marchandelec.com.

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Ouch, those 3 way Marchand's are a bit pricey for my blood!

I may have to settle for biamping instead of triamping anyway - can I actually do that? Use the active crossover to ..say ...split the mid and highs off to the D-75 amp to feed the mid-high part of my existing crossover, and run the woofers on the DC-300?
Or should I feed the bass and mids from the DC-300 and save the D-75 for just the slots (2405) -
I know they are rated for lower power ...

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Originally Posted by Rudy Kleimann

I second that recommendation on the Marchand kits. Was thinking of the same, but had a case of 'sometimers' with names while posting Saturday.

Of course, you could buy a Rane or Ashly used. Just make sure it's a recent design 24dB/octave Ashly and not one of the old ones, which in my experience didn't sound too good. Both brands sound great, and customer support is very good. The Ranes are more plentiful and less expensive, and I like the delay (driver alignment) function and CD EQ capability of the Rane models. ... My neighbor and I both use Ranes in our Audiophile systems with no disappointments in their sound quality.

Same for the little Crowns. I've used one of a pair of Crown Power Line Two amps for years to drive my HT surrounds, and though they're a little more powerful than a D-75, they wouldn't actually be overkill for the UHF as long as something crazy doesn't happen. I'll probably be using another one for my triamp project next year, pushing 2405's or similar. Use what you got... Truth is, he probably could do with 20 watts RMS if he has a smaller amp laying around. Try it out and see how it sounds.

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I know its not in the same class, but it looks like one of the Rane Active Crossovers might be a way to get my foot in the door at least. If I get a two way or a three way Rane I can at least get a feel for this dedicated bandpass amp. Besides - according to common wisdom, I still need to get some 2235 Woofers to get that deeper bass ...

Quote:

---

Originally Posted by norealtalent

I agree with Zilch on the 2215's vs 2235's. 2235's will have so much more bottom than the 2215's that you'll think you have 4 speakers. Also, 2231/2235 is the woofer that the 3133x is designed to work with. :bouncy:

---

About the marchands ... my philosophy on sound has always been that I have to be able to hear the difference an upgrade makes or I don't really need to spend the money. I appreciate all I am learning from the pros here, but my ears aren't as young as they once were, and there are so many places to spend money that I just can't put it all into the sound ...
I'm doing this to enjoy the music ...

I rehabed a pair of 4320s (see avatar) using the original drivers which included 2215s. I used the 3106 on the slots but bi-amped the woofer and horn at 1.2K. I bought a JBL Urei 6260 and 6230 power amp, as well as a 5235 crossover off of eBay.
With not that much money I was able to get these 4320s to sound better then they should. It requires patience and a bit of work.

Tom

Just got a "basket case" Harmon-Kardon Citation 22 that needs repairs.
I got a good deal on it - not too much money into it so far.
Anyway - I'm wondering what folks think of this amp from 1987-91 ?

I've heard good things about the classic HK amps, this one is rated 200w/Ch into 8 ohms, so I'm hoping for good things if I use it to run my 4320s

One plan - I have a 5235 on the way from Ian, and have already gotten a Crown D75 (for the 2405 slots) so the Citation 22 would have plenty of headroom to run just the woofers and horns if/when I biAmp.

Comments?
Things to look out for?
I've learned a lot here already - your feedback is always welcomed!

Quote:

---

Originally Posted by hjames

Just got a "basket case" Harmon-Kardon Citation 22 that needs repairs.
I got a good deal on it - not too much money into it so far.
Anyway - I'm wondering what folks think of this amp from 1987-91 ?

---

The Citation 22 is one of Giskard's favorite amps.

David

Quote:

---

Originally Posted by speakerdave

The Citation 22 is one of Giskard's favorite amps.

---

That's what I was thinking too... then I Googled it. The 22 is fairly pedestrian... it was the XX that he has praised so much... and it does appear to be quite special.

http://www.audioheritage.org/vbullet...6&postcount=14

Widget

He praised the 22 regularly and often recommended it at the prices it usually sold for on ebay.

He was rhapsodic about the XX and said that he must have been a little out of his mind the day he sold his. They are quite rare.

David

I have always confused simply praise with rhapsodic posts...:bouncy:


Widget

Geez! Now we're doing Giskard lore. Cripes!

Quote:

---

Originally Posted by speakerdave

Geez! Now we're doing Giskard lore. Cripes!

---

Even more Giskard lore - I just bought a pair of 2123s .... based on GT and Giskard's comments in the 4345 thread. Now I have to figure how to work them into my systems - or grow my systems to allow using them! Or hire Riessen to build some boxes (4344s?) - tho the shipping would no doubt break me!

Next stage.
Okay - the 2123 midBass speakers I got off ebay arrived today - they sound nice! Over the weekend I got a pair of JBL 2800 speakers (2 ways) - I figured I can use them as external donor cabinets for the midBass drivers, set them on top of my 4320s and begin a build process towards 4343/44 nirvana.

The cabinets are 22.5 x 11 x 9.5, a bit larger, but seem close to the size of the midbass "doghouse" used in 4343 cabinets (15 x 11.25 x 7, ballpark). Its a shame to gut perfectly working speakers, but they are cheaper models and all I really need are the boxes. Once I empty the cabinets of the old parts, I'll zilch-plug the port,
(is "zilch-plug" really a verb - or do you just "zilch" the port?) ... open the 8" woofer hole up to accept the 10" mid-woofer, and make a gasket (cork? motorcycle innertube?) to seal the midBass to the baffleboard.

Next step is rebuild my Giskard-type 3133 type crossovers for 4 way use ...

Once I have them working as working class version of the 4 ways, I can look into biamping them. I got a 5235 from Ian, and got a D75 from ePay, but I'm still waiting to hear back from the audio shop on the estimate for that Citation 22 I got last month ...

Read some reviews, went out and bought a router yesterday. From all I've read here I figured I'd need one to make the speaker mounting holes - I also thought out how to make a pair of "skids" that would (safely) ride around the front molding of the donor JBL2800 boxes, and allow me to cut the existing woofer hole larger, and make an indented shoulder for the speaker rims. It was below 40 last night but by mid-day it got a bit warmer, today so I set the shopmate up out back and took a shot at it. No garage or workshop, but at least the box-work is done before winter ...

Brought the boxes in and mounted the 2123s into the boxes ... not too bad! The funny "tweeters" in the bottom picture are the 2" zilch-plugs, 2 per box (one for the port, one fills the tweeter hole) .

'Course I can't DO anything with them yet until I rebuild the crossovers to 4344/45 spec ... back to Ian's upgrade threads for that!

Hi Heather,
NIce project. The bass issue (lack of bass) when you moved the cabinets to the top of the audio/video rack from the floor, is the result of:
The rack itself. The low frequencies are absorbed in the wood. The window behind the speaker cabinets is also a factor. The bass energy is also absorbed there.
The best location is on the floor next to 2 walls. I have my 4507 cabinets as follows:
The left side is next to a sliding door and a solid wall behind. There is a great deal of low frequency loss due to the sliding door. The low frequency energy is used to move the doors.
The right side is located at a 90 degree point. 2 solid walls. Bass response is extended. Both speakers are on the floor.

Try moving the cabinets where you first had them and listen for a while.

Ron

Quote:

---

Originally Posted by jbl

Hi Heather,
Nice project. The bass issue (lack of bass) when you moved the cabinets to the top of the audio/video rack from the floor, is the result of:
The rack itself. The low frequencies are absorbed in the wood. The window behind the speaker cabinets is also a factor. The bass energy is also absorbed there.
The best location is on the floor next to 2 walls. I have my 4507 cabinets as follows:
The left side is next to a sliding door and a solid wall behind. There is a great deal of low frequency loss due to the sliding door. The low frequency energy is used to move the doors.
The right side is located at a 90 degree point. 2 solid walls. Bass response is extended. Both speakers are on the floor.

Try moving the cabinets where you first had them and listen for a while.

Ron

---

Thanks for the tip, Ron, but without a complete rework of my entertainment room, there's really no place on the floor for them. Of course, I will have to pull them down off the shelf at some point just to pull the crossovers, and rework those into external crossovers (maybe like the ones Ian built) for 4-way use at first, then I can bypass part and biAmp them later. I also had a call earlier today that my Citation 22 has been checked out and repaired - I can pick it up later this week.

Its been over 6 months since I put the upgraded speakers on the shelves, and - I really miss the sound the speakers had closer to the floor. I've also got long term plans to rebuild these parts into a 4344 clone - but thats more long term. This weekend's project is to unpack the CDs and move their shelves into the front room - so I have floor space to bring the speakers down.

Compare the image to my avatar - so far I moved 2 of the shelves and go one speaker down onto some wheels - and brought down the smaller JBL cabinet I mounted the 2123 in - tho without a 4 way crossover its not yet connected.

But I can hear a renewal of the low bass just from the right speaker being down near the floor again!

I need to bring the left speaker down, then move the dual CD rack to the front room, take down the turntable and the gear on that top shelf, move the TV cabinet over a few feet, roll the teak equipment rack in beside it, and put the other speaker on wheels in the left corner ...

Maybe start on that tomorrow!

Glad to see you progressing toward your goal, Heather.

Just as important as the additional bass reinforcement will be having the midrange and tweeter nearer to ear level. I'm sure that acoustically you will like the new arrangement.

"Front room"--this expression reminds me of my father who always used it instead of "livingroom." Must be a regional colloquialism you share, but we are from upstate New York. Perhaps it is just "country."

David

Well, I think my kin used to call the front room "the parlor" - but to me, that denotes a room you use to entertain folks who are aren't coming very far into the home, perhaps a less-close neighbor or salespeople ...
Anyway, our living room (the "front room") has a cathedral ceiling, skylights, bookshelves and an amazing assortment of plants. Too visible from the street for big screen TVs or big speakers. We don't have much electronics there - didn't even have a phone in that room until recently. Its really more a reading room than anything else. Very comfy.

But thanks for the comments on sound placement - I'm excited to see how this goes!
I'm still learning what these speakers can do ... It hasn't even been a year since I got them - http://www.audioheritage.org/vbullet...ead.php?t=9273

Quote:

---

Originally Posted by speakerdave

Glad to see you progressing toward your goal, Heather.

Just as important as the additional bass reinforcement will be having the midrange and tweeter nearer to ear level. I'm sure that acoustically you will like the new arrangement.

"Front room"--this expression reminds me of my father who always used it instead of "livingroom." Must be a regional colloquialism you share, but we are from upstate New York. Perhaps it is just "country."

David

---

Hi, Heather.

Try this: turn off the midrange and then listen for the vertical beamwidth of the slot tweeter, moving up and down. That's the window you must be listening in to hear it well; it's a relatively narrow 25° at 16 kHz according to the text here:

http://www.jblpro.com/pages/pub/components/2405.pdf

The slot has to be aimed at or near ear level for best listening.... :yes:

Quote:

---

Originally Posted by Zilch

Hi, Heather.

.... it's a narrow 25° at 16 kHz according to the text here:

http://www.jblpro.com/pages/pub/components/2405.pdf

The slot has to be aimed at or near ear level for best listening.... :yes:

---

It's just a thought, but you could also try, just as an experiment, rotating the slot 90 degrees to horizontal instead of vertical. You might have to angle the boxes in slightly to compensate though.

Finally moved the other speaker down and spun the slots 90 degrees. We also moved the center cabinet and TV area, and got my old equipment rack back in the system. There's always more to do, but you can see the 2123s in their own box on top (not currently connected) - that gives you an idea of what I'm planning at least.

I built those for a trial listen and see if building a set of 4344 clones from these parts is a worthwhile change. For that I'll need a pair of Giskard Equivalent CC networks for the 4344.

But thats longterm - I still have to build cards for the 5235 crossover, and wire that up to the Citation 22 and Crown D75 I got, and see what effect biamping has on the system ... but thats probably early next year!

Gotta bake cookies next weekend - I hear the Holidays are coming!

Woo HOO, Heather, very nice. I am inspired!

Gonna move mine up from the dungeon and rework 'em.

Different approach, but I think you'll like the result.

[Think Model 19.... :thmbsup: ]

Looks much nicer now ... and much smoother listening too I suppose. :thmbsup:

Quote:

---

Originally Posted by hjames

Finally moved the other speaker down ...
We also moved the center cabinet ...
There's always more to do ...
I built those for a trial listen ...
I still have to build cards for the 5235 crossover ...
Gotta bake cookies next weekend ...
I hear the Holidays are coming!

---

There are still 24 hours left each day. :thmbsup: :thmbsup: :thmbsup:
___________
Peter

Heather,
Your setup is looking great!:thmbsup:

Ron

Quote:

---

Originally Posted by jbl

Heather,
Your setup is looking great!:thmbsup:

Ron

---

yes.... much more Feng Shui friendly.... :bouncy:

No BS, these DO sound better than the shorter horns when used with 800 Hz crossovers, Heather.

Even *I* can hear the difference.... :p

http://audioheritage.org/vbulletin/s...864#post138864

Quote:

---

Originally Posted by Zilch

No BS, these DO sound better than the shorter horns when used with 800 Hz crossovers, Heather.

Even *I* can hear the difference.... :p

http://audioheritage.org/vbulletin/s...864#post138864

---

Saw your post this evening ... Very cool - but the hard part is to find a pair of the longhorns! Any ideas ... ?

Another point is to consider that I hope to rebuild mine towards 4344/45 specs - If the new Giskard's equivalent networks are like the original of the 4345s, which uses the crosspoints of 290hz, 1.3k and 10k, I won't need to be crossing that low anyway (besides, recommendations are to biamp at the low crosspoint ... ).

But thanks for the heads up - another possibility is always good!

Quote:

---

Originally Posted by hjames

Very cool - but the hard part is to find a pair of the longhorns! Any ideas ... ?

---

Lookin' at about $100 a pair, apparently:

http://cgi.ebay.com/Vintage-JBL-H-92...QQcmdZViewItem

The system evolves again!!

Over the weekend I bought a pair of L200 cabinets (unbadged) from a seller in Aberdeen, MD. Sunday I moved my 2215s and 2420/2307/2308 driver/horn/lens parts into the box. I've got the 3133 crossover and 2405 slots on top for now, but I plan to mount them in the JBL 2800 boxes that hold the currently unused 2123 Midbass. Long term plans are to make this whole thing into a 2 box version of the 4344s - much work to do ...

The L200s were the consumer version of the 4320 Monitors, parts are virtually interchangeable (2215 = LE15, etc) but the L200s have more WAF, and if I find a set of 4343/4344/4345s cheap, the L200s will sell quicker than the old beaterbox 4320s. They have become ...
The Phoenix Project!!

Anyway - they aren't 4320s anymore, so the thread continues here:

http://audioheritage.org/vbulletin/s...=L200+Aberdeen

And the empty 4320 boxes & grills?? They're going to BMWCCA this weekend - so its his project now!

Quote:

---

Originally Posted by Woofer

yes.... much more Feng Shui friendly.... :bouncy:

---

Quote:

---

Originally Posted by hjames

They have become ...
The Phoenix Project!!

Anyway - they aren't 4320s anymore, so the thread continues here:

http://audioheritage.org/vbulletin/s...=L200+Aberdeen

And the empty 4320 boxes & grills?? They're going to BMWCCA this weekend - so its his project now!

---

You kids meeting in the middle, or are you heading South with Emma on Sunday? Don't want to rudely invite myself, but let me know if there's going to be a Pow-Wow in my backyard, or if I could be a convenient meeting point for you both. I'd be happy to host you, even if it's just for a transfer of goods from CR-V to BMW. My van's here, too if BMWs don't fit big project speakers, let me know if I can help at all.

je

P.S. I brought Jean to Gayle's so she could see the hams, all we bought was bacon but we'll be back- thanks for the tip.

Phil's headed my way Sunday - gonna fit it in with a run visit inlaws up here I think. Emma's moved the church service from 6PM to 4 PM so she'll head out earlier and be home sooner. I don't usually go with her - Sunday's my decompress time, play loud music, etc ...
I'm recovering from this flu bug thing - today's the first day back at work - Emma may be getting it now (!) ...
Gotta pick up glass tonight for L200 speaker tops - protection for the wood!
Maybe I'll have time to bore holes in the 2600 baffleboards so I can mount the 2405s soon ...


Not - enough - hours ...
must - focus - efforts -
must - not - sway ...

:applaud:

Quote:

---

Originally Posted by Fred Sanford

You kids meeting in the middle, or are you heading South with Emma on Sunday? Don't want to rudely invite myself, but let me know if there's going to be a Pow-Wow in my backyard, or if I could be a convenient meeting point for you both. I'd be happy to host you, even if it's just for a transfer of goods from CR-V to BMW. My van's here, too if BMWs don't fit big project speakers, let me know if I can help at all.

je

P.S. I brought Jean to Gayle's so she could see the hams, all we bought was bacon but we'll be back- thanks for the tip.

---

Gotcha- Jean's going to FLA to visit her mother all next week, so it'll be loud music & motorcycling all week while she and the puppies are gone...

je

Quote:

---

Originally Posted by hjames

must - not - sway ....

---

Heh, heh.

Your two-way L200 evaluation kit has shipped.

[Gonna be interesting.... :p ]

Big time fun! Thanks Zilch.

So - should I buy that AudioGone guy's gainclone for $200 that spwal has been talkin' about to run me tweets?

He says 50w/ch of clean sound - separate p/s - http://cls.audiogon.com/cgi-bin/cls....ran&1178422173

You know Storm would never appreciate it ....

Quote:

---

Originally Posted by Zilch

Heh, heh.

Your two-way L200 evaluation kit has shipped.

[Gonna be interesting.... :p ]

---

The "Kit" includes a $30 T-Amp to run the HF.

[It's 10 watts, and you'll never get it past 9:00.... :p ]

The thread Moves on ....
after working with the 4320 cabinets and various add on parts, I got a pair of L-200 cabinets (much more spouse-friendly!) , and moved the drivers and crossovers into them!

Follow the thread here:

Looky What I just got - Those Darned L200 Cabs (from Aberdeen)

Feb 18, 2006, we made a trip to Top 10 Music in Glenolden, PA to pick up a pair of 4320 speakers I won through an ebay auction ...

Hard to believe all that's passed since that day 8 years ago!

Before them, all I knew of JBL was my friend Jimmy's L100s and the L-36 decades I bought new in 1976 ...

Well, I would say you made it around the block at least twice!! :D

I'd almost die for a pair of empty ones (I got all the bits), at an affordable price, here in Australia, just to add to the collection.
They're still quite a good box when used sensibly. (and a couple of minor mods to x-o's etc)

Hi JBL fans and speaker devotees.

I bought a pair of 4320's with the added JBL 075 bullet tweeter a lot of years ago, and then emigrated, and they've been sitting in storage ever since...

In the meantime, some sub-human thieves broke into my property and stripped the 15" drivers from the cabs, and also one 075 bullet tweeter and an L91 acoustic lens, and ran off. :-( Why steal one tweeter and one lens?) My original and beautiful 15"s are probably in the back of some deaf idiots car now, as subs.. (mmm... where's my shotgun?)

So, originally the cabs were veneered but someone had taken a sander to the tops to 'clean them up' and destroyed the veneer. I sanded and sealed the carcasses and rollered them with grey paint with added sawdust in the paint roller tray. Excellent finish now, and they look great. I want to use them as my main studio monitors, so I'm almost happy ( and I will be totally happy if I can decide how to proceed from here).

I bought a pair of JBL Northridge 15" drivers as replacements last week (330757-001's ) and I realise that they are not as per the original JBL 15"s specs (they are 98db sensitivity and 225 w. rms into 8 ohms ) but am I likely to be able to tell the difference? Or, alternatively, should I use the 15"s elsewhere, and try to locate an original and correct replacement vintage pair of JBL 15"s... ??

I also wonder about the bullet. Many people say that omitting the tweeter is smoother and gives not such a harsh top-end but still retains a smooth upper-end detail. Is this true? (I have the original twin side-by-side crossovers in each cab) but have no knowledge of what they sound like without, and as per their original spec. Now I have bass drivers, I can of course test them and disconnect the one bullet I have.

Do you think I'm better to try to buy a single replacement JBL 075 bullet (not cheap) or sell the 075 I have, and buy something like a new pair of;
http://www.ebay.co.uk/itm/33359-Professional-Heavy-Duty-Titanium-Bullet-Tweeter-Speaker-300-W-8-ohm-18-Oz-/271040890280?pt=LH_DefaultDomain_3&hash=item3f1b4b c5a8


Alternatively buy a pair of ribbon tweeters at 30 watt handling each and craft the cab fronts to suit?

what would you excellent JBL folks recommend please? and has anyone got a spare L91 lens that they want to sell? or should I buy a new plastic replacement pair from Japan. ?

Has anyone any opinions about the new wooden lenses?

I'm using two pairs of JBL Control 5's and a JBL sb5 as mid field monitors just now, and they're really great, (excellent and very underrated speakers) but I really want to install the 4320's with or without the original 075 bullets, or maybe with bullet / ribbon substitutes, as my main studio monitors.

all assistance and advice (and if possible an L91 lens :-) gratefully received (and the lens purchased of course) :-)

regards


ritchie
bg (Bulgaria)

I would recommend your getting a pair of JBL 2235H woofers and put them in your cabinets. They are the more modern and arguably superior woofer designed to go in those cabinets. You can order a replacement L91 lens from Kenrick Sound in Japan. Here they are on eBay. I believe they will sell singles.

Don't know what to say about the tweeters. If they were mine, I would look for a clean pair of JBL 2405s or 077s.


Widget

Quote:

---

Originally Posted by ritchie

Hi JBL fans and speaker devotees.


Do you think I'm better to try to buy a single replacement JBL 075 bullet (not cheap) or sell the 075 I have, and buy something like a new pair of;
http://www.ebay.co.uk/itm/33359-Professional-Heavy-Duty-Titanium-Bullet-Tweeter-Speaker-300-W-8-ohm-18-Oz-/271040890280?pt=LH_DefaultDomain_3&hash=item3f1b4b c5a8


Alternatively buy a pair of ribbon tweeters at 30 watt handling each and craft the cab fronts to suit?

what would you excellent JBL folks recommend please? and has anyone got a spare L91 lens that they want to sell? or should I buy a new plastic replacement pair from Japan. ?

ritchie
bg (Bulgaria)

---

Hi RITCHIE,

I would suggest you to buy JBL driver of the same type ALNICO (075) or FERRITE (depending your type), and if its diaphragm is wrong to buy Original D16R2402 .
I have bad experience with "aftermarket diaphragm", and would not suggest anybody to use them.

regards
ivica

Quote:

---

Originally Posted by ivica

Hi RITCHIE,

I would suggest you to buy JBL driver of the same type ALNICO (075) or FERRITE (depending your type), and if its diaphragm is wrong to buy Original D16R2402 .
I have bad experience with "aftermarket diaphragm", and would not suggest anybody to use them.

regards
ivica

---

Thanks for both replies..

1) How would I tell if my remaining 075 tweeter is alnico or ferrite? It has the single side -bolted circular frame retainer, that slips over the front of the bullet and retains it in the port, and it's not the front- 4 x screw-mounting model.

2) Is the Northridge JBL 2235H woofer so much different to the Northridge JBL 330757-001 woofer?

advice really appreciated and thanks again..


regards richard
bg

Quote:

---

Originally Posted by ritchie

Thanks for both replies..

1) How would I tell if my remaining 075 tweeter is alnico or ferrite? It has the single side -bolted circular frame retainer, that slips over the front of the bullet and retains it in the port, and it's not the front- 4 x screw-mounting model.

2) Is the Northridge JBL 2235H woofer so much different to the Northridge JBL 330757-001 woofer?

advice really appreciated and thanks again..


regards richard
bg

---

Unfortunately Richie, your location makes it tough, but yes, I too would recommend trying to source a single 075.
Post a Wanted Ad here and see what happens. I'm sure someone here would have one. Worst case scenario, is that I know someone who might be persuaded to sell you one, but it's in Australia, so postage would be really expensive.
I'll ask him in the meantime to see if there's one spare and the cost, but it'll be working at least and highly likely to have an original diaphragm. I'll know more tomorrow as it's night time here now, and everybody [except me] is in bed…..
As far as what you have, it would have to be an AlNiCo, only because those boxes are older than when ferrites came out. [I think…. anyone feel free to correct me if I'm wrong.]

Now as far as the 15" are concerned, try to locate a pair of JBL 2215. They come and go. They're actually one of only a couple of woofers from that series that have an fs of 20Hz.
Depending on just how loud you want to take these things, I feel they'll be more than adequate, and the 4320 is actually tuned to them to start with.

Forget about the Lenses for now. EVERYBODY I know, including myself has soon learnt that the box sounds great without them.
If you're mainly a single person listener, then dispersion is the last thing you should be worried about, as you just end up sitting in the 'sweet spot' anyway, so no need to worry about what it sounds like 'off axis'.

I'll get back to you in a day or so about the 075….

Cheers.

ps: I will add, that it's the box that makes the bass sound what it is. If you're a low level SPL listener, you could just about throw anything in the way of a 15" woofer in them, and they'd still sound great to a non-critical listener, and you just might be happy with it until you could find and afford the real things. At least you could still be enjoying the use of them while you're waiting…. ;)
[let the arguments begin…. LoL]

Quote:

---

Originally Posted by ritchie

Thanks for both replies..

1) How would I tell if my remaining 075 tweeter is alnico or ferrite? It has the single side -bolted circular frame retainer, that slips over the front of the bullet and retains it in the port, and it's not the front- 4 x screw-mounting model.
...
regards richard
bg

---

Hi ritchie,

look !

reagrds
ivica

Yes, do look at the above pics.
…. and be aware, a JBL 2402 is the same as a JBL 075. Just a different foilcal [badge] and paint.
The ferrite 2402 will have an 'H' suffix after the model number. e.g. JBL 2402H

Quote:

---

Originally Posted by Woofer

Yes, do look at the above pics.
…. and be aware, a JBL 2402 is the same as a JBL 075. Just a different foilcal [badge] and paint.
The ferrite 2402 will have an 'H' suffix after the model number. e.g. JBL 2402H

---

Thanks so much for the valuable help to everyone..

I have a ferrite 075 then, no black paint at all, only black paint on the rear dust cap.(but no rear suffix 'H' after the model number , and only 'Model 075'.) Impedance 8 ohms. and Serial Number 70325.

Regarding the 15's, I'm totally confused :-(
I looked up the frequency response graphs of both the JBL 2235H and the JBL 330757-001's (that I bought as replacement woofers) and I could not see much difference in the graphs at all. :-((

The bottom end (on both) at around 20hz does not seem to kick in until 25hz or so, at negligible levels, and then more reasonably at 85db at 25hz or so (on both) and then they both jump to 90db (or a very more respectable 98db in the 330757-001's case.) at around 40hz.

I see that the response of the 330757-001's is less linear and more peaky, and I recognise that the later-manufactured 330757-001's are generally used as low-powered PA sub-drivers, but I can't see much difference at all in the specs, or am I reading them incorrectly? Are the JBL 330757-001's so inferior to JBL 2235's??

The 330757-001's seem to have a really solid bottom end, and they're certainly defined and tight (I'm driving them with a 300wpc rms Bose power amp, and at concrete building-shaking levels:-)

The horns seem a bit washy and indefinite and the mid-range is a bit rubbish and ill-defined.. Recorded speech does not sound natural, and the top end is definitely absent..
I can't understand how listeners could say that without the 075 tweeters, that they are listenable or usable at all.. Even with the horn crossover cranked up, crash and ride cymbals and hi-hats are almost non-existent.. :-(

But I suppose I'm maybe trying to compare the sound of my 2 x pairs of control 5's and control 5 sb, and the 4320's are a generation older and possibly a bit lacking in comparison.
But they look really good in their new textured grey livery, and their cleaned black front cloths and lovingly polished escutcheon plates, and I shall persevere !!
Of course, the wife says that the 4320's are far too big.. but I realise that no-one ever said that life was going to be a bowl of cherries, so I just don't listen.. :-))

thanks to all.

ritchie
bg

Just as an experiment, reverse the wiring [phase] on your 15", and see if your midrange improves at all.
It's worth a shot…..

Quote:

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Even with the horn crossover cranked up, crash and ride cymbals and hi-hats are almost non-existent

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…. but if you bypass the 075's x-over, [disconnect it completely, but only for now 'till u get a replacement ring] you may find the mid/highs will extend because the horns then aren't being rolled off by the high x-over.

ps: I've forwarded a link to this thread to a mate. He may be able to help with a replacement ring.
I've asked him to PM you direct.

Quote:

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Originally Posted by Woofer

Just as an experiment, reverse the wiring [phase] on your 15", and see if your midrange improves at all.
It's worth a shot…..

I tried the phase coherence with a meter, and checked that bass response in the centre was reinforced and also in the 'sweet spot' so I think the 15"s are in phase, but I shall check the horns phase.


…. but if you bypass the 075's x-over, [disconnect it completely, but only for now 'till u get a replacement ring] you may find the mid/highs will extend because the horns then aren't being rolled off by the high x-over.

OK.. Thanks again Woofer. I shall try that.. It really makes sense when considering my mid-range symptoms and the washy sound and complete loss of top-end.. Great!


ps: I've forwarded a link to this thread to a mate. He may be able to help with a replacement ring.
I've asked him to PM you direct.

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Many thanks again... good people..

regards

richard

Is there anything more that I should know about the 4320 crossovers please?

For example, would the capacitors or any other crossover components deteriorate after 45 years, and fluctuating storage temperatures over that time?
Bulgaria gets down to minus 20 celsius and up to plus 38 celsius (over 100 farenheit) and the monitors have been stored for a lot of years in a non-air-conditioned building.

I note from other 4320 posts that the mid-horns should be out of phase with the bass drivers and the tweeters?
This is presumable to time-align the mid range at centre listening position?


many thanks for everyone's help.

regards

ritchie
bg