Upgrading DIY JBLs?

[martin2395]

Hello Everyone,

I have recently bought a pair of big custom built JBLs, they sound fabulous, but I'm curious if there are any simple mods to make them even better?
Here's a pic of the current setup:
55581

They have:
1x 2445J mid driver on JBL2395 slant plate horn
2x 075 tweeters
2x 2205B woofers

The are being tri-amped with two Urei 6260 power amps for low and mid section and a simple Philips FA931 amp for the highs (maybe in the future I will get the 6290 for the lows)

Greetings from the Netherlands!
Martin

[louped garouv]

swapping the 075s for 077s (or pro equalivents),
and possibly adjusting/optimizing the XO point
may help reduce beaming of the UHF...
but is that what you want? ;)

what are your xo points being used?

[martin2395]

At this moment the lo/mid xover point is at about 800Hz, the mid/hi one is at 7000Hz. These were recommended by the previous owner and also by JBL.
The only problem i have is getting all units at even volume, it's kinda difficult with 5 volume knobs :) I don't know if this is a fault in the design but the 075's don't blend with the 2445J, it's somewhat like 3 different speakers in one box.

[Lee in Montreal]

Very nice system my friend. The strong point of the bullet tweeters is the ability to be crossed at 3KHz, but it's weak point is that it tops around 14KHz. I would replace them with a 2405 slot tweeter at 7Khz or 8KHz. I also suggest to raise the boxes so that the lenses are at your head level. Most likely your speakers were a club install, and were hung from the ceiling.

You have a great set-up only requiring some fine tuning. If I were you here's what I would do. Your mids could go from 500Hz to 7Khz. This is the first channel you should start playing with. Then introduce the tweeter(s). Raise or lower the volume until it sounds right. At the end, raise the bass level until it sounds balanced. Take note what your levels are. The day after, repeat the same sequence. And the day after. Until you are satisfied. Basically, in the first 15 seconds you power up your system, you'll know if it sounds right or not. After, your brains are adjusting... You may also want to time align your drivers. Basically all sources shall be aligned so that sounds start from the same point at the same time. It can be dne physically, or digitally.

My last recommendation is to remove te passive crossovers and replace them with one active unit that will give you better control.

[martin2395]

Thank you Lee!

I'm running them tri-amped with Behringer CX3400 active xover (rather crappy, I'd stay away from them for home use, they are very noisy)
however they also have JBL3105 passive filters on the back, that I don't use, I tried them in combination with a JBL M552 2-way xo but it didn't sound too well as the 2445J are very efficient and I couldn't increase the volume on the 075's.

It's a pity that the 2405's are so hard to find (and expensive as hell) here in the Netherlands. I was even thinking about buying 4 ones with broken diaphragm and use the ones from my 075's.
I will also defineatly build some nice wooden stands for them, something like Kenrick Sound's JBLs use.

So would you recommend lowering the xo point between the highs and mids? I think that I'll stay with 800Hz between lows and mids, as this is the lowest frequency recommendend by JBL for the 2395 slants. I have read that they were designed for disco's and stuff like that but for home use they sound really amazing, very spacious and extremely detailed!

[Lee in Montreal]

I have some 2395 myself, attached to some 2441. JBL specifies 800Hz if the rear baffles are not used, but 500Hz if they are. I don't think your 2205 with felt domes sound nice above 500Hz.

Without rear baffles
http://img.photobucket.com/albums/v668/Lee_Vuong/JBL%20parts%20factory/DSCN0919.jpg


With rear baffles
http://img.photobucket.com/albums/v668/Lee_Vuong/JBL%20parts%20factory/DSCN0904.jpg


In regard of the CX3400, I had one and it is not a bad device. It is quieter than most digital units that are not set-up properly. The CX3400 only have very limited functions but it is great as a first crossover.

[martin2395]

I haven't used the 2395 without rear baffles yet, I will give it a dry with the frequency lowered to 500-550Hz.

The CX3400 has nice features but the noise is just unbearable.

[Lee in Montreal]

In regard of the noise/hiss, I suspect it is because your amp's attenuators are fully open while your pre-amp is at a small percentage of its capacity. Raise your pre-amp o 75%. Then set the power amps' attenuator to the level you expect to use. This is a very common problem, whatever the brand of active crossover.

[martin2395]

Well, maybe i've got a faulty Behringer but i'm sure this is the reason of the noise, everything is set on 100%/normal volume, the only volume control are the volume knobs on the amps, which are mostly set on 30-40%. The old JBL M552 was really perfectly quiet so it can't be the amps.

p.s
I lowered the xover frequency to 500Hz.....spot on! Bass became much more powerful and the sound is more spacious, it just sounds better.

[yggdrasil]

You could try to cross in the 075 higher than 7K, e.g. at 9-10K.

[martin2395]

Do you think it will be a good idea to let the 2445J go so high?

Though, lowering the lo/mid xo point was really an improvement, the bass has a lot more punch now.
Do you think that replacing the 2205's with 2235H's would improve the bass even further?

[Lee in Montreal]

That's good news. Have you measured the distance betwee the 2445 diaphram, 2402 diaphragn and 2205 domes? You can calculate the delays to apply to the 2242 and 2205 to start aligning them. Your 2445 is the furthest back, so it should stay at zero. Delay the others and align them on the 2445..

[Mannermusic]

Well, maybe i've got a faulty Behringer but i'm sure this is the reason of the noise, everything is set on 100%/normal volume, the only volume control are the volume knobs on the amps, which are mostly set on 30-40%. The old JBL M552 was really perfectly quiet so it can't be the amps.

p.s
I lowered the xover frequency to 500Hz.....spot on! Bass became much more powerful and the sound is more spacious, it just sounds better.

Yes, and it would be even better if you would add a mid-bass driver right where the 075s are and then put the UHF - either 075 or 077 - on the top. Like the 4355 except with a big (!) horn/lens. I ran a 3-way tri-amp similar to yours for 25 years and never was satisfied with the musical fundamentals (200 - 1200 Hz). The mid bass fixes that. I cross at 260, 1200, 8-9,000. You can use Giskard's 3155 network for the treble and bi-amp the bass. The big 3-way is just fine for night club/PA/rock&roll but if you are interested in Hi Fi, I'd consider 4-way. Not sure what you are looking for. Many ways to "skin a cat!" Neat project. Mike

[Lee in Montreal]

The big 3-way is just fine for night club/PA/rock&roll but if you are interested in Hi Fi, I'd consider 4-way.

I second that. I think that the 200 to 800Hz is crucial for hifi. Vocals, snare drums.... Sadly no 15" woofers goes up there, and no compression driver goes that low. Therefore a front horn loaded 12" driver could work the 100Hz to 800Hz range. Leaving all the thump to the woofers. It is actually my next step. If only I could find some affordable 2206...

[more10]

I think that the 200 to 800Hz is crucial for hifi. Vocals, snare drums.... Sadly no 15" woofers goes up there, and no compression driver goes that low.

JBL 248X. Radian 950PB. JBL 244X with Radian 2445 diaphragm. BMS 4591. They all are usable from 300.

[martin2395]

Sadly, I don't think I can replace the 075's with a midbass, the 4355 has a 12 inch mid, does it? If so it won't fit there for sure.
However I may try to place it like mids in the 4312 but then with two woofers.

Changing the 2445 to something else that can go from 300Hz would be the easiest, though I'm unsure how it would sound with the 2395.

p.s
I can have a pair of 2204H's for €160, would it be an improvement?

[hjames]

Why not try a 10 inch mid-bass like the 2121, 2122 or 2123?
You can leave the woofers on the low bass ... bring the mid bass in from,
say 300 to 1200, and let the horn driver start there.
Sell the bullets and get a 2405 supertweeter and get one of Lee's aluminum mounts
to float the slot tweeter above the slant lens ...



Sadly, I don't think I can replace the 075's with a midbass, the 4355 has a 12 inch mid, does it? If so it won't fit there for sure.
However I may try to place it like mids in the 4312 but then with two woofers.

Changing the 2445 to something else that can go from 300Hz would be the easiest, though I'm unsure how it would sound with the 2395.

p.s
I can have a pair of 2204H's for €160, would it be an improvement?

[martin2395]

I have found something like 2123H's, these are 10 inch and will probably fit with ease. I'm only unsure about their price, €250 for a pair...
The description is not correct as there are no 2321's , so this must be 2123H's.
Here's the link: http://link.marktplaats.nl/553413948

[Odd]

I have found something like 2123H's, these are 10 inch and will probably fit with ease. I'm only unsure about their price, €250 for a pair...
The description is not correct as there are no 2321's , so this must be 2123H's.
Here's the link: http://link.marktplaats.nl/553413948


2123h will be right for you. The two you linked to does not look good. Keep an eye on eBay.com and eBay.de They are often for sale. In the U.S. approximately $ 100, - each.

[martin2395]

Can you tell me what's wrong with them? :) He has 12 of them available and 4 have been recently reconed.

by the way, when I'm back home, I will try putting the 2395 higher so the 075's can fit directly under, I'm very curious how it will sound.

[hjames]

Can you tell me what's wrong with them? :) He has 12 of them available and 4 have been recently reconed.

by the way, when I'm back home, I will try putting the 2395 higher so the 075's can fit directly under, I'm very curious how it will sound.

If the pix below are the speakers you are referring to, they appear to have accordian surrounds.

The 2122 and 2123 speakers I have seen have foam surrounds -
my guess would be the advertised speakers have greatly different specs.

Take a look at the comparison picture we got from Subwoof in this thread from a few years ago ...

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=25462&stc=1&d=1180663503

You can scroll to the bottom of the page listed here to see all the images and specs in the matrix.

http://www.audioheritage.org/vbulletin/showthread.php?16962-Field-Guide-to-the-JBL-10-inch-Midbass-driver-2121-2122-2123/page2



Compare them to the Image I grabbed from the ad you linked to



55595

[Odd]

Can you tell me what's wrong with them? :) He has 12 of them available and 4 have been recently reconed.

by the way, when I'm back home, I will try putting the 2395 higher so the 075's can fit directly under, I'm very curious how it will sound.


Perhaps they are right?

55596

[1audiohack]

Post 22 looks like a proper 2123. The pic at the bottom of post 21 looks to be an E110 with at best, an incorrect dust cap and black painted, but more likely an aftermarket E110 cone kit with a less than stellar glue job.

E110's have very short voice coils and VERY thin cones, like 0.022" thick, the 2123 has a longer coil and thicker cone. We're it me, it would be a proper 2123.

All the best,
Barry.

[martin2395]

I have repositioned the 2395's to make some place for the tweeters:

http://i49.tinypic.com/15d4b9.jpg

[hjames]

Check this thread for Lee's aluminum mounting brackets

The H stands for the horn/lens combo
http://www.audioheritage.org/vbulletin/showthread.php?32285-JBL-2505-H-stands-aluminum-repros

http://img.photobucket.com/albums/v668/Lee_Vuong/JBL parts factory/DSCN0946.jpg

or the L bracket for the slot tweeters
http://www.audioheritage.org/vbulletin/showthread.php?29920-Stainless-steel-brackets-for-2402-2404-2405&p=300397&viewfull=1#post300397 (http://www.audioheritage.org/vbulletin/showthread.php?29920-Stainless-steel-brackets-for-2402-2404-2405)

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=48769&d=1291214801

[martin2395]

They look really cool!
Btw, what do you think, are they placed right, or should I move them further to the front? At this moment they are about 5cm from the edge:

http://i49.tinypic.com/2rdhk6x.jpg
I must admit that I like that industrial style of the original brackets, pity that someone cut a part off the right one :(

[hjames]

Well, you could time-align them by positioning the drivers so the diaphragms are in the same vertical plane ...
but I think you'd need the bullets to be on top of the horn driver,
or else the lens would shroud them and block their dispersion to some degree ...



They look really cool!
Btw, what do you think, are they placed right, or should I move them further to the front?
At this moment they are about 5cm from the edge:

http://i49.tinypic.com/2rdhk6x.jpg
I must admit that I like that industrial style of the original brackets, pity that someone cut a part off the right one :(

[Lee in Montreal]

Knowing the speed of sound is 344m/s, measure the distance between the 2402 and the 2445 (distance between diaphragms. Divide this distance by 344 and you shall know by how much time you should delay the tweeters to time align them with the 2445. Then it is only a mater of precise tweaking from your seat. Works the same with the woofers.

If, per exemple the tweeters are 0.390m ahead of the 2445, then 0.390m divided by 344m/s = 1.133720930233e-03s or 1.13 millisecond delay. Your CX3400 has up to 2 millsecond delay. So you are golden.

[Lee in Montreal]

I must admit that I like that industrial style of the original brackets, pity that someone cut a part off the right one :(

Hmmm... I make aluminum repros. Or I can sell that single iron stand for $75.00cad

http://www.audioheritage.org/vbulletin/showthread.php?32285-JBL-2505-H-stands-aluminum-repros

[martin2395]

Thank you Lee!
I have sold the CX3400 and ordered the DCX2496 which should be even better as everything can be set more precisely.
The only reason I moved the tweeters is to make place for a midwoofer.

I will give them a listen when the DCX arrives :bouncy:

[Lee in Montreal]

Changing the 2445 to something else that can go from 300Hz would be the easiest, though I'm unsure how it would sound with the 2395.

Hi Martin

A friend of mine, Eaulive, who's also a member here, and myself have purchased a pair of empty 4520 at the same time from the same guy. But we developped our systems in different ways.

I have a three way and Eaulive has a four way. The difference being he has a 12" B&C midbass and I can attest that it makes a huge difference in vocals and snares. Therefore I will also add a mid bass 12" front horn loaded cabs when I find good ones.

[martin2395]

I wil add there an extra midbass speaker, though i think it will have to be an 8 inch :(

If I only haven't sold my EV VMR's a few months ago! :D

[more10]

Changing the 2445 to something else that can go from 300Hz would be the easiest, though I'm unsure how it would sound with the 2395.

You will have to replace the 2395 with bigger horns, like these (http://www.hififorum.nu/forum/topic.asp?TOPIC_ID=82919):

55605

[yggdrasil]

Do you think it will be a good idea to let the 2445J go so high?

The 2445's go there. Not sure about your horns and beaming. With active and adjustable crossovers it is easy to try.

Johnny

[martin2395]

I decided to buy a pair of new mids, as most of the second hand JBL's that come up on Marktplaats have been abused and badly reconed. Yes I know that this maybe sounds stupid but...is it bad if it says "good/optimized" for guitar? I saw this by a lot of 10 inch drivers such as Eminence Delta or Gamma.

[Lee in Montreal]

Time to find a proper design for a front horn loaded cabinet.

[martin2395]

Let me guess....they are HUGE? :p

[Lee in Montreal]

Let me guess....they are HUGE? :p

A front horn loaded cabinet for a 10" driver will perhaps be only 13" tall x width of your current bass bin. Not that bad. And they are not very difficult to build. Nothing that can't be done in a day. Your mids and tweeters are high efficiency, and you need the front horn of that new cabinet to help you raise the acoustic efficiency.

Have a peek at Eaulive's album

http://www.flickr.com/photos/eaulive/5644860122/in/set-72157626260334894/lightbox/

[martin2395]

I understood you wrong, I thought you meant a complete front loaded horn cabs like Eaulive's 4520's as these would never fit to my room :)

By the way, do you have any recommendations for 10 inch midwoofers, except old JBL units?

[Lee in Montreal]

Maybe the usual B&C or Eminence ;) Could as well pick up a pair of 12"

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=294-660

[martin2395]

Hello Lee,

Would placing the midwoofer there where the 075's were be very wrong? :) I mean, I sit about 3.5-4m from the speakers and while the room is 2.3m high I think that it may sound "strange" with midwoofers placed so high. My room is quite small and that's why I try to keep the units close to each other :)

[Odd]

You have most of the parts for a 43xx monitor. Be patient and wait for two 2123h/2121h/2122h. Sell ​​the 2395 lenses, and buy something that fits better in smaller rooms. Use only one 075 or purchase a 077/2405. Read posts about 4343,4345,4355. Once you have all the components will possibly someone on this forum help you with a 3-way crossover for the HF section.

4343 (http://www.audioheritage.org/vbulletin/showthread.php?16951-4343-References-Thread)
4345 (http://www.audioheritage.org/vbulletin/showthread.php?10490-The-JBL-4345-Club)
4345 (http://www.audioheritage.org/vbulletin/showthread.php?27199-DIY-quot-4345-quot-Project)

Search in LHF with Google, it's better than the forum search.

[martin2395]

Most of the parts? As far as I know none of the units I currently own was used in the 43xx series ;)

[hjames]

Most of the parts? As far as I know none of the units I currently own was used in the 43xx series ;)

Of course not, but if you are working a DIY system, look at the parts list for successful commercial/Pro models to see what you approach.
Why not emulate something successful?

I cranked my L200s into 4333 territory with a crossover upgrade and adding 2405 slot drivers ...

[jbl4ever]

You can check into 2404 tweeters. If you want to keep your cabinet these should fit the baffle.

[pos]

I decided to buy a pair of new mids, as most of the second hand JBL's that come up on Marktplaats have been abused and badly reconed. Yes I know that this maybe sounds stupid but...is it bad if it says "good/optimized" for guitar? I saw this by a lot of 10 inch drivers such as Eminence Delta or Gamma.

Wayne has this front loaded 10" design that uses an Eminence Delta 10 (or JBL 2012H)
http://www.pispeakers.com/catalog/product_info.php/cPath/4/products_id/104
http://audioroundtable.com/forum/index.php?&t=msg&th=16581