My 4520 project

[Eaulive]

I started a set on flickr, for whoever's interested.
I'm not to keen on finishing but I'm making a big effort. When I see the craftmenship of some forum members here I feel very ashamed :o:

Basically I'm gonna build a set of 4520 with a completely home brewed midbass horn and 2370/2426 as HF.
It's gonna be triamped with eventually a good digital processor but for now all I have is an old DOD :)

The midbass horn will house a B&C 12PE32 but I will eventually get some E120 or similar.

http://www.flickr.com/photos/eaulive/sets/72157626260334894/

[more10]

Nice project!

The 4520 have an ugly dip at 150 Hz from first out of phase interference. How low will you let the E-120 horns go?

I have never heard the 2370 horns, but I believe that a tractrix or lecleach will sound better. Why use 4?

[Eaulive]

Nice project!

The 4520 have an ugly dip at 150 Hz from first out of phase interference. How low will you let the E-120 horns go?
I plan to start them at about 125~150 but before I'm gonna measure the 4520 to see exactly what response they have and how to work around the flaws.



I have never heard the 2370 horns, but I believe that a tractrix or lecleach will sound better. Why use 4?
Because I have them :D and because stacking 2370s vertically increases the gain significantly and narrows the vertical pattern at lower frequencies.
And also because this setup will also be used for high SPL from time to time :dj-party:

[Eaulive]

I'm leaving now for Champlain NY to pick-up my four C8R2225 :applaud:

[Lee in Montreal]

I'm leaving now for Champlain NY to pick-up my four C8R2225 :applaud:

Wished I had ordered two from you. I have an installed pair of 2225h with cones that look and measure exactly like original JBL parts but lack the bass the other pair has. I switched amps, channels, wires. It remains the same. To make sure the problem is not a nearby wall, even with my head inthe scoop, one side is missing the lower bass. I suspect the cones are JBL, but from another driver with different coil depth... :eek:

[Eaulive]

Wished I had ordered two from you. I have an installed pair of 2225h with cones that look and measure exactly like original JBL parts but lack the bass the other pair has. I switched amps, channels, wires. It remains the same. To make sure the problem is not a nearby wall, even with my head inthe scoop, one side is missing the lower bass. I suspect the cones are JBL, but from another driver with different coil depth... :eek:

Last test is to try them in the other cabinet.

[Lee in Montreal]

Last test is to try them in the other cabinet.

Indeed. But I doubt there woud be such a difference. Boith 4520s were the same. And I used the same sound damping in both units (Walmart egg crate shaped mattress foam - $5.00 for 18" x 24")

[Eaulive]

I'm uploading the pictures of the day on flickr.

http://www.flickr.com/photos/eaulive/sets/72157626260334894/with/5581194522/

[maxwedge]

Looking nice!

[Eaulive]

I have an installed pair of 2225h with cones that look and measure exactly like original JBL parts

By look is hard to tell, do you have markings on the back of the cone that says what cone it is?

[Lee in Montreal]

I'm uploading the pictures of the day on flickr.

http://www.flickr.com/photos/eaulive/sets/72157626260334894/with/5581194522/

Your set of 4520 is definitely not the same construction as mine.

[Eaulive]

Your set of 4520 is definitely not the same construction as mine.

I took the first two next to the door, but I noticed the scoop was different.

[Lee in Montreal]

I took the first two next to the door, but I noticed the scoop was different.

I suspect that yours are made from 3/4" presswood, not 5/8" as mine, as your framing seems thicker than mine.

[John]

I suspect that yours are made from 3/4" presswood, not 5/8" as mine, as your framing seems thicker than mine.

Do any of these 4520 cabinets have a cut out on the top surface of cabinet near the front center with a recessed terminal plate with 2 pairs of JBL style terminals? :hmm:

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[Eaulive]

Do any of these 4520 cabinets have a cut out on the top surface of cabinet near the front center with a recessed terminal plate with 2 pairs of JBL style terminals? :hmm:

50771

No, those are not made by JBL, but by a local sound company that made tons of them in the 70s, 80s.

[Lee in Montreal]

The reason why I bought these cheap $200 4520s despite their age and flaws was to study their construction. I haven't yet found the ideal location for a connecting plate. Also, I am surprised that JBL didn't include a brace on the center of the front panel up to the rear panel. Not much wood at the front and certainly a weak area, prone to vibrate. Originally, the rear panel wasn't even braced to the forward panel and only had two timbers to dampen the vibrations. Not to mention that I suspect that the enclosure's dimensions were partially dictated by JBL's bean counter wanting to put as much of the 4'x8' sheets in that box. Sides are 48" tall + 2 x 0.75", which means less cut, less waste, cheaper to produce. I would do the same if I were a business.

Basically, many mods have been made by people who have reproduced these cabinets in order to make the cabinet less resonant. So, an original 1970s 4520 might be great for collectors, but most likely, any other iteration from a third party is probably better constructed.

[jcrobso]

I used a pair of 4520s for a Church sound system as subs, loaded them 2226s and crossed them over at 100HZ if I remember correctly. I could shake the whole room with them.
If you want to use 12' speaker for a mid I would suggest a JBL 2206 it is an excellent speaker.
http://www.jblpro.com/pub/components/2206.pdf

[Eaulive]

More recones :applaud:
http://www.flickr.com/photos/eaulive/sets/72157626260334894/with/5618187086/

50903

[maxwedge]

You've got some work to do!:D

[Eaulive]

You've got some work to do!:D

Yup, and I still miss two baskets :blink:

[Lee in Montreal]

Yup, and I still miss two baskets :blink:

I have empty baskets ;-)

[Eaulive]

I have empty baskets ;-)

I know you do, don't tease me :banghead:

[subwoof]

I have made hundreds of the single and doubles since 1980.

Yes there are numerous bracing and pathway mods that improve performance but remember that when the factory cabs were popular the majority of speakers and amplifiers were WAY below the 200 watt level so those parameters didn't come into play.

The most popular model I made was a single 18 variant of the 4520 - it could fit through normal doors, had a large mouth and went deep enough ( singularly ) for the SR guys who rented to raves.

sub

[Eaulive]

Nice weather today, I finished my midbass horn prototype, we'll see tomorrow if the weather allows some sweeps :D

Don't mind the quality of work, it's a rough prototype, unfinished and it's not for the living room.

I'm a butcher :p

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Full set here: http://www.flickr.com/photos/eaulive/sets/72157626260334894/

[Lee in Montreal]

Nice.

100Hz to 800Hz?

[Eaulive]

Nice.

100Hz to 800Hz?

theorically the cut-off is 125Hz, we'll see after that how high it goes before going bezerk but I hope to reach 1k.
The driver goes flat to 4k according to specs but I doubt the construction allows it.

[Lee in Montreal]

2118j ?

[Eaulive]

2118j ?

Nope, B&C 12PE32, for lack of an E120 or a 2204H :(

[Lee in Montreal]

Hey Olivier.

Today I will reinforce the front baffle as it tends to vibrate (not buzz) even at medium output level. It think the front baffle is a very weak point. I will simply brace it with the baffle behind. Iptimally, it should be two 3/4" skins, or one HDF 1", still with bracing. I am very happy having purchased these cheap 4520s as it allows me to clearly see the weakness and improve the forthcoming units I will make.

[Eaulive]

Good!
Experimenting, I like it :)

I sweeped my midbass cabinets today but even outside there's a lot of reflections, first sweep gave me a sharp 20dB null at 400Hz, I almost put the box on the curb :banghead:

The backyard is very small, around 16' between the house and the fence, so I tried different positions and I came up with this.

At first there was no damping in the back box, so I made some runs with no cover, with damping, etc.

This is the result I get, which is not so good but there's too much reflection in this back yard.

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This is at 2m on-axis from the horn mouth, not the driver, with 4VRMS.
At 300Hz the SPL is 106.1dB, I checked it with my SPL meter for reference next to the microphone I use for the sweep.

Microphone Earthworks M30
Audio interface Lexicon Lambda
Software DSSF5E

So much for loading down to 125Hz but it should be useable from 150Hz to 1.5kHz with some EQ

[Eaulive]

Another weekend without working on this project.
Because I have another project :D

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[maxwedge]

So is that so you don't have to stop to relive your self? Good idea after a long day of beer drinkin!:p:eek:

[Eaulive]

So is that so you don't have to stop to relive your self? Good idea after a long day of beer drinkin!:p:eek:

or how Canadian winter can take a toll on automobiles :crying:
This is very common on vehicles 15 years old or more, fortunately we became experts in fixing this, the goal here is to avoid inspection, not to have a new truck :D

[maxwedge]

or how Canadian winter can take a toll on automobiles :crying:
This is very common on vehicles 15 years old or more, fortunately we became experts in fixing this, the goal here is to avoid inspection, not to have a new truck :D
Glad I live in California right now:), with all that bad weather back east right now.:(

[hjames]

Glad I live in California right now:), with all that bad weather back east right now.:(

I dunno about bad weather, here in the DC area, it was nice all week,
with just a bit of spring rains today ...

[Eaulive]

Glad I live in California right now :)

I don't, too many vehicle inspections over there :D

[maxwedge]

I dunno about bad weather, here in the DC area, it was nice all week,
with just a bit of spring rains today ...
That's good to hear. I'll be going through your woods in the last week of July on vacation.:)


I don't, too many vehicle inspections over there :D
Yes it does suck for the one's who take care of their vehicles.:(
I even have to have my Dodge diesel smog checked now. They just do a smoke check and visual. I'll give them smoke! :die:

[Eaulive]

Ok, I'm out to make the first test with those babies.
Today is the first day of the rest of their lives :D

I hope my friend's neighbours love loud music... I'll keep you posted.
:dj-party:

[maxwedge]

Break any windows yet??:eek::p

[Eaulive]

Well, just came back.
Since they're in my friend's garage and he has a tight schedule, I just wanted to drive them.
Didn't have time to make any measurements and obviously I didn't make any adjustments, just rough crossover points and that's it.
No EQing, no correction. The 2426s need to be tamed and the midbass horn has something I don't like but for today it was only juice :applaud:

It didn't last for long, neighbours came out running asking how long this was going to last.

I know I got the SPL though, we measured 115dB SPL (C weighting) at 10meters with a pink noise. :bouncy:

This translates to 135dB at 1m, litterally ear splitting.

I'm gonna have to find a far away place to be able to calibrate this properly :banghead:

4520 with freshly reconed 2225H on E140 frames, powered with 2 Crown XS 700, 450W@8ohms in each driver.
DIY midbass horm with a B&C 12PE32 powered by a Crown XS500, 400W@8ohm in each driver
Four 2426J on 2370 horns powered by a Crown XS500, 400W@8ohm in each pair (200W in each driver)

Pictures :applaud:

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[1audiohack]

Kick ass!!! Just looks like fun!

[maxwedge]

Friggin' awesome!

[hjames]

ZOMG - that looks like too much fun -
they'd kill us around here if I started to play with something like that!


Well, just came back.
Since they're in my friend's garage and he has a tight schedule, I just wanted to drive them.

It didn't last for long, neighbours came out running asking how long this was going to last.

I know I got the SPL though, we measured 115dB SPL (C weighting) at 10meters with a pink noise. :bouncy:

This translates to 135dB at 1m, literally ear splitting.

I'm gonna have to find a far away place to be able to calibrate this properly :banghead: :applaud:
http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=51744&d=1308344304

[Lee in Montreal]

Hey Olivier.

Time to spend $50 on casters now. It might save you $500 in chiropractor later :D

[Eaulive]

New avatar for the cause :D:applaud:

[1audiohack]

That's just too cool!

[badman]

why you would insist on using a wimpy double 15" scoop cab instead of a true dual 18" 25Hz horn.....


;)


Very kickazz looking system!

[Lee in Montreal]

why you would insist on using a wimpy double 15" scoop cab instead of a true dual 18" 25Hz horn...

Don't worry about that. I am working on it, and Eaulive will probably follow after I build mine.

[Eaulive]

Don't worry about that. I am working on it, and Eaulive will probably follow after I build mine.

Man, I have storage problems already :banghead:

[Lee in Montreal]

Man, I have storage problems already :banghead:

Don't store them. Use them daily in your living room. Properly equalized and timed, the 4520 can become hi-fi.

[Eaulive]

Don't store them. Use them daily in your living room. Properly equalized and timed, the 4520 can become hi-fi.

That's my plan, as soon as I get a living room :D

[Lee in Montreal]

That's my plan, as soon as I get a living room :D

Get a big one as when I build my new twin 18" 4520s you might end up with my current cabinets... Four 4520 in you mofo living room... :eek:

[Eaulive]

Get a big one as when I build my new twin 18" 4520s you might end up with my current cabinets... Four 4520 in you mofo living room... :eek:

I still have to measure and listen to a 4520 compared to two 4530, to see if it's really worth it to have those back breakers.
Of course with the same drivers.

[Eaulive]

Ok, had a party this weekend, it cost me a 2225H :banghead:

Now I was really not driving that hard, it was very quiet for the whole afternoon when my nephew wanted to hear a specific song so I cranked it up for 30 seconds... then I heard a buzz...buzz...BUZZ...BUZZ...BUZZ...BUZZ.

Sh*t :crying:

VC arced against the top plate, just at the place where the wire goes down vertically to the bottom of the coil, making the whole thing thicker.
Then the wire started dropping in to the gap and it was the end, about 1/3rd of the wire was unrolled into the bottom of the magnet. No signs of heating, burning, melting or deformation whatsoever.
Varnish gave up?

I don't know if JBL screwed up with their tolerances or if it's me when I reconed it.
I have the doubt because the first four C8R2225 I received had to be returned to JBL because they were soooo visually out of specs. (they didn't even argue with me) The one that burned saturday "looked" OK, but... :dont-know:

The two first I reconed were in use in a friend's 4530 for a while, and they took more abuse with a 600W amplifier, they are still alive.
The amp I was using this weekend was 450W.

I still don't understand :banghead:

[Lee in Montreal]

Maybe there was some coil rubbing thru the varnish as you mention... :dont-know:
Did you use a high pass filter to protect the driver from VLFs and excessive excursion? Nothing happens below 30Hz anyway with that driver anyway. Might well cut-off there. Perhaps the very low frequencies moved the coil beyond its comfort zone, flexing the spider and suspension, moving the coil out of alignment. Which would have caused the rubbing. This is unlikely, but perhaps possible. I feel sorry for you.

Please let us know what you meant by one of the recone kit being out of specs? Where they the new "Hecho en Mexico" recone kits?

[Eaulive]

Maybe there was some coil rubbing thru the varnish as you mention... :dont-know:
Did you use a high pass filter to protect the driver from VLFs and excessive excursion? Nothing happens below 30Hz anyway with that driver anyway. Might well cut-off there. Perhaps the very low frequencies moved the coil beyond its comfort zone, flexing the spider and suspension, moving the coil out of alignment. Which would have caused the rubbing. This is unlikely, but perhaps possible. I feel sorry for you.

Please let us know what you meant by one of the recone kit being out of specs? Where they the new "Hecho en Mexico" recone kits?

Yep, I have the driverack with a 24dB/oct LPF at 30Hz.
I'm usually very cautious when I crank up the volume, I dont run the amps into clipping, I listen and control depending on the program material, I'm no AKTTR freak (All Knobs To The Right)

The first batch of four C8R2225 I received from JBL were made in Mexico.
There was two among those that were instanly rejected, on one the former was shorter than the length of the coil causing the end of the winding to be wound up in free air. (yes you read me right, I'll send you pictures)
And a badly wound VC on the second, the first 2 or 3 turns looked like wrinkled spaguetti.

The two that were good I installed and Stéphane used them in your old 4530 connected full range to a XS900 (600Wpc) He gave them a good blast for longer runs than I did. I remember feeling the heat on the cone and dust cap after one session.

Now it's one from the new batch that died. On this batch there was visually no flaws AFAIR.
However I wrote a little dot on the back of the cone and this must mean something but I don't remember what :banghead:

Now I have doubts, maybe something was wrong and slipped my visual inspection? Maybe I screwed up when I did the recone?
Further inspection of the core will maybe tell me.

[jcrobso]

Hey Olivier.

Time to spend $50 on casters now. It might save you $500 in chiropractor later :D
They were on sale for $19.00

[jcrobso]

Ok, had a party this weekend, it cost me a 2225H :banghead:

Now I was really not driving that hard, it was very quiet for the whole afternoon when my nephew wanted to hear a specific song so I cranked it up for 30 seconds... then I heard a buzz...buzz...BUZZ...BUZZ...BUZZ...BUZZ.

Sh*t :crying:

VC arced against the top plate, just at the place where the wire goes down vertically to the bottom of the coil, making the whole thing thicker.
Then the wire started dropping in to the gap and it was the end, about 1/3rd of the wire was unrolled into the bottom of the magnet. No signs of heating, burning, melting or deformation whatsoever.
Varnish gave up?

I don't know if JBL screwed up with their tolerances or if it's me when I reconed it.
I have the doubt because the first four C8R2225 I received had to be returned to JBL because they were soooo visually out of specs. (they didn't even argue with me) The one that burned saturday "looked" OK, but... :dont-know:

The two first I reconed were in use in a friend's 4530 for a while, and they took more abuse with a 600W amplifier, they are still alive.
The amp I was using this weekend was 450W.

I still don't understand :banghead:
If you can get USA made 2226 they might do a better job.

[OLDGEN]

here is my horns:bouncy:

[OLDGEN]

I have another pair of 4520:bouncy:

[Eaulive]

Another party this week-end... no victims :D

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[Lee in Montreal]

Nice pair... :D

[Eaulive]

It is indeed beautiful :applaud:

[Lee in Montreal]

Hey Oli, I'd be curious to know how you have set your crossovers points. I am asking as I have just tried a 6db slope at 90Hz with Q-1.4 and it works nicely. I also run a 6bd boost at 35Hz, the 4520's cut-off.

[Eaulive]

Hey Oli, I'd be curious to know how you have set your crossovers points. I am asking as I have just tried a 6db slope at 90Hz with Q-1.4 and it works nicely. I also run a 6bd boost at 35Hz, the 4520's cut-off.

I set them up for SR, and I have a 12dB/oct HPF at 30Hz and _if I remember well_ I cross them at 150Hz at 12dB also.

I have to check my driverack and I'll tell you.

I didn't do much tuning on them so far, and all by ear.

[Lee in Montreal]

I set them up for SR, and I have a 12dB/oct HPF at 30Hz and _if I remember well_ I cross them at 150Hz at 12dB also.

I have to check my driverack and I'll tell you.

I didn't do much tuning on them so far, and all by ear.

I found that tuning by ear brought the nicest results. I use the RTA only to ensure I didn't do anything stupid, or just to fine tune some small areas. If I rely on the RTA only and get a flat response, I find the sound boring. So, I guess I love "coloration"...;)

BTW When do you have time to work on my three Yamaha P2200? :D

[Eaulive]

I found that tuning by ear brought the nicest results. I use the RTA only to ensure I didn't do anything stupid, or just to fine tune some small areas. If I rely on the RTA only and get a flat response, I find the sound boring. So, I guess I love "coloration"...;)

BTW When do you have time to work on my three Yamaha P2200? :D

My kids are leaving next week, so I guess I will be more quiet after this, I'll let you know :D

[Eaulive]

Ok, it was the next party of the season today. A private school to which I'm very related had its "back to school" party so they ask if I had the SPL... I said oh yeah! :D

It was outside but even if I had a license to drive all I wanted, I had to keep about 10-12 dB below max to be sure not to endanger the kid's ears.

We made a safe area circle with cones around the stacks (3 meters) because some kids wanted to sit in the scoops.
Even with this and the volume down I had peaks at 115dB 3 meters away. :bouncy:

Pictures will come soon.

No 2225 got hurt in the process.

[Lee in Montreal]

... because some kids wanted to sit in the scoops.

What's wrong with that? Bass is good. You probably spotted the bassheads...

[Eaulive]

What's wrong with that? Bass is good. You probably spotted the bassheads...

Indeeds but parents would not approve :no:
I wouldn't let my kids do it either, not at that volume.

[Lee in Montreal]

I am telling you, bass is good... :eek:

52716

[Eaulive]

:D Hey, I can do the same :D

[grumpy]

Just spare us any personal reenactment of the 'vintage' pic shown here ;):

http://www.decware.com/imperial.htm

[Eaulive]

I have a picture of my ex wife laying on my subwoofers, we we married she turned them into a couch :D

[Eaulive]

Pictures just arrived

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[Lee in Montreal]

One of my cats is a real basshead. Picture taken while a movie was playing :D.

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[Eaulive]

Okay, today was the big day.
Me an a friend gathered some 4520s, 4530s, 2225H, 2225H on E140 frames, E145, Pyramid woofers and really cheapo speakers, also Cerwin-Vega P36 and two kinds of 18 inchers (not JBL).

I'm gonna post the results of those tests here because it answers some questions I had about bass scoops.

All the readings were made with 3.75VRMS at the driver, taken at a distance of 13'.
This was the setup that gave us the most consistent readings dealing with reflections, wind noise and other stuff.
I didn't want to get too close to the speakers and also I didn't want to drive the whole neighbourhood crazy with sweeps (I didn't succeed with this part however :D )

My goal today was to make sweeps of the 4520 and the 4530, to check the difference between Stéphane's original 2225H and my 2225 mexican cones on E140 frames (1.35T motor)
Also I wanted to properly time align my midbass and midhigh units.

Test # 1: 4520 with E140 as 2225, 3.75VRMS at each driver taken at 13'

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I took a reading of 102.4dB @ 4m with 3.75 V in each driver, it gave me -32dB on the graph which means that the -30dB line represents approximately 111dB SPL @ 1W/1m

[Eaulive]

Now we took a 4530 with the same driver, again 3.75VRMS at 13'

52777

Major difference in bottom end, falls more rapidly below 60Hz, also a good 5dB lower ioverall, even if there's only 3dB less in power... mutual coupling works :)

[Eaulive]

This is the same 4530 but with an original 2225H

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More or less the same, the difference is _maybe_ a little less low end and a little more top end for the E140 frame, that would be consistent with the predictions of a stronger motor.

[Eaulive]

Finally, I wanted to check 2 4530 side to side versus one 4530 with the same drivers.

Blue: 4520, orange: 2x 4530

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Draw your own conclusions :D

[Eaulive]

Last task was to try to set the delays and EQ on my stack of 4520/midbass horn/2426/2370.

I arrived to this final result. I could do better maybe, but I had no time.
Impossible to do better below 200Hz though, the design of the 4520 has a phase reversal inherent to the design.

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[Eaulive]

Pictures here!
http://www.flickr.com/photos/eaulive/sets/72157626260334894/detail/?page=7

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[pos]

Nice experiment! Thank you for sharing!!
The 4530 has a dip around 130Hz (more like 150Hz for the 4520) that seems typical of the scoops.


More or less the same, the difference is _maybe_ a little less low end and a little more top end for the E140 frame, that would be consistent with the predictions of a stronger motor.
A stronger moto should give you for midbass efficiency (higher mass break point) but should leave the lower part unchanged, which seems pretty much consistant with what you measured.
(to compare you can open each graph in a different tab in your broswer: 2225H (http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=52778&d=1315188413), E140/2225H (http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=52777&d=1315188342))


Now why don't you start buying (or building) W-bins?
(I know they are quite rare on your side of the ocean, whereas they are plenty in europe)

[stephane RAME]

Hi Eaulive,
The measurements are done with the cat? :D
It takes two cats for the stereo. :D

Stéphane

[Eaulive]

:D Hey, I can do the same :D

I wanted to take this picture but never got around to it :D:applaud:
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http://www.flickr.com/photos/eaulive/sets/72157626260334894/with/6310979828/