5 cu-ft bass boxes for 2225H

[doucanoe]

Hey Guys,

Anyone care to post some pics of their cabinets they have constructed for a JBL 2225H woofer. I came across an nice one locally and I think its going to solve my desire to build a subwoofer.

From what I have read here, This driver wont bring me to the depths of hell itself but with the right cabinet, I should be able to get cleanly down to 40 cycles.

I found the JBL 5 cu-ft cab plans here but was curious if anyone has came up with another cabinet design? Just looking for some ideas.

Also, Im thinking seriously about driving this with a plate amp. I know that the 2225H has high power handling capabilities but is at the same time very efficient. Suggestions regarding plate amp power minimums would be appreciated also.

Thanks, RC

[jbl]

The 2225 in the 4507 cabinet will give you sufficient bass (32Hz) where no sub is necessary. I've had mine since 1985. The slam is great.

Ron

[Zilch]

I just don't get it, apparently. Why's so many trying to make "subs" outta 2225/6? Fine for SR or bass horn, of course, but reconing thrashed 2225's to 2235H and tuning 5 cu.ft. 2507 by plugging one or two ports is a direct path to real bass (as opposed to quasi-bass) performance, with the further advantage of potential use as the core of credible two- and three-way systems.

2225/6 PAIRS can offer hassle-free subwoofing in TCB alignment, tho, if you've got room for it:

http://www.jblpro.com/pub/obsolete/4685.pdf

See also:

http://audioheritage.org/vbulletin/showthread.php?t=6289

Yeah, it's 15 cu.ft., but a pair of 2507's is 10.... :p

Again, my appeal: WHO'S GOT ACCESS TO ONE OF THESE TO DOCUMENT FOR THE FORUM?

[doucanoe]

I just don't get it, apparently. Why's so many trying to make "subs" outta 2225/6? Fine for SR or bass horn, of course, but reconing thrashed 2225's to 2235H and tuning 5 cu.ft. 2507 by plugging one or two ports is a direct path to real bass (as opposed to quasi-bass) performance, with the further advantage of potential use as the core of credible two- and three-way systems.




Well, I guess a guys got to make due with what he has available to him I guess. Just to clarify, I only have the one and I would like to make good use of it. No recone necessary.

RC

[Zilch]

http://www.jblpro.com/pub/obsolete/4647.pdf

-10 dB at 35 Hz.

4685 is -10 dB at 28 Hz....

[doucanoe]

Yea daddio!

Thats what Im looking for.:D
Now I just have to find one or make one.
Thanks
RC

[Zilch]

Thats what Im looking for.:D
Now I just have to find one or make one.O.K., it's four 3" dia. ports, 6.25" long.

Close one of the ports with a plumber's test plug to try extending the bass a bit. That retunes the box from 40 to ~35 Hz.

A pair of empty 4507's sold in your neck of the woods recently, so they're out there.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7388698371&rd=1&sspagename=STRK%3AMEWA%3AIT&rd=1

Talk to this seller about just the box, maybe, if you have a way to get it:

http://cgi.ebay.com/JBL-4647A-Low-freq-speaker-and-enclosure-used_W0QQitemZ7401391083QQcategoryZ47094QQssPageNa meZWDVWQQrdZ1QQcmdZViewItem

[doucanoe]

Dang, I missed the pair right in my own backyard.

Thanks again Zilch, Now I know exactly what Im looking for!

RC

[doucanoe]

Well, I havent found a 4507 cab yet but a friend and member here (ejfud) called me today to let me know he found a old Pilot cabinet for me. He didnt know if the size was right but figured that it would be pretty close.

I stopped by after work to check out his new speaks and check out the cabinet. His guess on the size was pretty accurate. We hard calculated it out and it's a little over 5.5 cu-ft internal. I need to cut a new baffle for the driver and ports. Im going to use 2 or 3 dependent on diameter and use the length(s) suggested.

2-questions if I may:
*Should the port length change because of the greater internal volume?
*Does the port length include the depth of the baffle or measured from the inside of the baffle?

RC


I think she is going to clean up very nice and bring a little "retro chic" into the project.

[Zilch]

Port length changes with volume change, yes.

Port length is measured from front of baffle.

You'll likely need to add bracing to that Pilot box. Find the pics of empty 4507 I've posted. It's cross-braced with 2x4's.

That's quite a handsome box you've found there, actually. :thmbsup:

BB6P results:

Red = 4507
Green = 4507 with one port closed as suggested above
Black = Pilot box tuned to 33.75 Hz

That's two 4" dia. X 6.646" long ports, or,
three 3" dia. X 5.624" long, or,
four 3" dia. X 8.725" long.

High pass at 30 Hz if you're gonna play it loud. You're cone displacement limited down there at rated 200W. Some plate amps have that option built in.

That's about as low as I can reasonably get 2225H to play for you. You can see I've given up 1.5 dB at 50 Hz to gain 3 dB at 30 Hz, since you want a "sub." There's others here more skilled with BB6P than me who might have better recommendations....

Edit: Pic at bottom shows how JBL does the bracing. It's an added plywood block (glued and stapled) with shelf into which 2x4 is glued (and screwed, in others).

[EXCUSE the dust.... :p ]

[Zilch]

The 2225 in the 4507 cabinet will give you sufficient bass (32Hz) where no sub is necessary. I've had mine since 1985. The slam is great.Hi, Ron!

Plug one of the ports with 3" plumbers' test plugs and tell us what you hear, please.... :)

[doucanoe]

Hi, Ron!

Plug one of the ports with 3" plumbers' test plugs and tell us what you hear, please.... :)

Zilch, I will do that and report back. The Pilot was very well braced oddly enough but it will need to be removed to get at the baffle (front) I am going to brace like your 4507 after the new baffle and driver is installed.

Got the amp/xover situation covered last week with a stop at one of my local audio haunts. They had a very nice NHT SA3 subwoofer amp in their consignment room. This amp is pretty substantial at 250 w/ch into 6ohm and has high and low pass controls at the rear panel. :thmbsup: It ran me a little more that the somewhat equivelent powered plate amp but I think I will be much happier with it in the long run.

The sad part is that even though this could be up and running in a few hours (short of a cabinet refinish) We are leaving for a little vacation Monday morning. That means I will be working Satruday and if I start working on the sub Sunday, my wife would have my head. LOL. It will have to wait for another week.

Thanks again for the port clarification and the re-calc.

RC

[Zilch]

Zilch, I will do that and report back.Hee, hee. That was for the OTHER Ron.

[You won't need to plug nothin' once you get your new baffle/ports installed....] :D

[doucanoe]

Hee, hee. That was for the OTHER Ron.

[You won't need to plug nothin' once you get your new baffle/ports installed....] :D


I was wondering why I should provide the port and then plug it? I thought maybe it would get up and dance around the room or something :D

RC

[ejfud]

Hey that looks like my garage! Oh wait that is my garage.

Found this in a junk store and thought of Ron's sub project right away. I'm as excited to see it done as he is.

Gary

[jbl]

Hi, Ron!

Plug one of the ports with 3" plumbers' test plugs and tell us what you hear, please.... :)
Hi Zilch,
I tryed your suggestion and here's what I found:
First off, I attempted this as a listening test with various CDs. I didn't check WIN Isd before listening so that I would be open to what I was hearing.
The overall sound was about the same, except on a Bob James CD. There was a noticable dip at about 40 Hz. The result was a muddying effect. I didn't hear it on all CDs, but taking out he plug corrected it on that disc. I'll try more CDs over the weekend.

Ron

[4313B]

The result was a muddying effect.Have Zilch check the group delay in BB6P. Stock and then with one port blocked.

[Earl K]

- This entire line of reasoning ( running a 2225H in a cabinet tuned below the speakers resonance and operated in a system alignment that is less than a "critical alignment ) is iffy at best .

- I'll admit it's a great way to magically turn the short coil 2225 into a long coil 2235 ( after you've had the recone kit installed ).

- I realize that in home HiFi it seems that almost anything goes but that doesn't make it right ( or best practise ). What's happened to using the right tool for the job ?

- I've used 24 , 2225Hs in system alignments that are critically damped while being tuned to 52 hz for over two decades. I've never burnt a coil or had one toss its' cookies and leave the gap ( & this is SR work ). These were all used without subs for a good 15 years. They do a fantastic job at creating fake bass when electronically enhanced ( LF boost ) & used in conjunction with a VLF high pass filter. Treat the 2225 right and it'll last forever. It's a great driver .

- The 4671 ( Cabaret ) had terrible unloading problems due to the system tuning being too low and the 2225H operating in an oversized enclosure. Yes, you can "derate" the input power for such practice / but in SR ? / & in real life ? / it just never happens & things just blowup .

- There are reasons to not tune these speakers below their Fs ( at least this & previous generations of JBL woofers ) . Perhaps the newer deep-gappers ( 1/2" deep ) can withstand this abuse better / I don't know since so far I haven't persued answering that specific question.


:)

[4313B]

Perhaps the newer deep-gappers ( 1/2" deep ) can withstand this abuse better / I don't know since so far I haven't persued answering that specific question.They can and do but...

In any case, nice post Earl. It looks like both you and Zilch appreciate the "right tool for the job" concept that I've been trying to convey since day one. There really is a reason why the 2225H is labeled a "2225H" and the 2235H is labeled a "2235H" and neither is labeled "all purpose woofer". :p

[Zilch]

Group delay of 2225H and 2235H in 5 cuft 4507 box per BB6P.

2225H:

Black = stock, 4 ports open, ~40 Hz tuning
Orange = 1 port closed, ~35 Hz
Red = 2 ports closed, ~28 Hz

2235H:

Green = 1 port closed, ~35 Hz
Blue = 2 ports closed, what I normally run here, ~28 Hz

[4313B]

Interesting Zilch... So he can hear that change in transient character eh?

[Zilch]

Interesting Zilch... So he can hear that change in transient character eh?Seems pretty minor, no? And all well below the Blauert & Laws curve of group delay audibility.

In my experience, just about any change I make I'm gonna be hearing a difference in some instrument on some cut on one test CD or another. It may be a room or box resonance in this low range, as well.

Just part of the fun of playin' with tunings. :p

I'm with you and Earl here. As I said above, this ~35 Hz tuning is pushin' 2225H about as far as I can resonably conceive it playing well in this box. I do have some 2225H's here I could try myself to confirm....

[jbl]

- This entire line of reasoning ( running a 2225H in a cabinet tuned below the speakers resonance and operated in a system alignment that is less than a "critical alignment ) is iffy at best .

- I'll admit it's a great way to magically turn the short coil 2225 into a long coil 2235 ( after you've had the recone kit installed ).

- I realize that in home HiFi it seems that almost anything goes but that doesn't make it right ( or best practise ). What's happened to using the right tool for the job ?

- I've used 24 , 2225Hs in system alignments that are critically damped while being tuned to 52 hz for over two decades. I've never burnt a coil or had one toss its' cookies and leave the gap ( & this is SR work ). These were all used without subs for a good 15 years. They do a fantastic job at creating fake bass when electronically enhanced ( LF boost ) & used in conjunction with a VLF high pass filter. Treat the 2225 right and it'll last forever. It's a great driver .

- The 4671 ( Cabaret ) had terrible unloading problems due to the system tuning being too low and the 2225H operating in an oversized enclosure. Yes, you can "derate" the input power for such practice / but in SR ? / & in real life ? / it just never happens & things just blowup .

- There are reasons to not tune these speakers below their Fs ( at least this & previous generations of JBL woofers ) . Perhaps the newer deep-gappers ( 1/2" deep ) can withstand this abuse better / I don't know since so far I haven't persued answering that specific question.


:)

Well said Earl. I'm VERY happy with the sound of the 4671 system. Been that way since 1985. Never felt the need for a sub. If I did, it would have been there a long time ago.

Ron

[jbl]

Well said Earl. I'm VERY happy with the sound of the 4671 system. Been that way since 1985. Never felt the need for a sub. If I did, it would have been there a long time ago.

Ron
Hi Zilch,
Try your 2225 vs 2235 and tell us your impressions. Also, try the 2225 with 1 port closed and see if you hear what I heard.
Thanks

[paragon]

This was an 4508 (8 cf) with two 2205A. Very good speaker. Response to 40 Hz in corner. Old pic, no data. Think 2225 in 5 cf is similar.

[jbl]

This was an 4508 (8 cf) with two 2205A. Very good speaker. Response to 40 Hz in corner. Old pic, no data. Think 2225 in 5 cf is similar.
Yes. The response is the same.