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Thread: 5 cu-ft bass boxes for 2225H

  1. #1
    Senior Member doucanoe's Avatar
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    5 cu-ft bass boxes for 2225H

    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

  2. #2
    jbl
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    Thumbs up

    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

  3. #3
    RIP 2011 Zilch's Avatar
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    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/s...ead.php?t=6289

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

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

  4. #4
    Senior Member doucanoe's Avatar
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    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

  5. #5
    RIP 2011 Zilch's Avatar
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    http://www.jblpro.com/pub/obsolete/4647.pdf

    -10 dB at 35 Hz.

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

  6. #6
    Senior Member doucanoe's Avatar
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    Yea daddio!

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

  7. #7
    RIP 2011 Zilch's Avatar
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    Quote Originally Posted by doucanoe
    Thats what Im looking for.
    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...MEWA%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-fr...QQcmdZViewItem

  8. #8
    Senior Member doucanoe's Avatar
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    Dang, I missed the pair right in my own backyard.

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

    RC

  9. #9
    Senior Member doucanoe's Avatar
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    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.
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  10. #10
    RIP 2011 Zilch's Avatar
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    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.

    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.... ]
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  11. #11
    RIP 2011 Zilch's Avatar
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    Quote Originally Posted by 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.
    Hi, Ron!

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

  12. #12
    Senior Member doucanoe's Avatar
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    Quote Originally Posted by Zilch
    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. 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

  13. #13
    RIP 2011 Zilch's Avatar
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    Quote Originally Posted by doucanoe
    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....]

  14. #14
    Senior Member doucanoe's Avatar
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    Quote Originally Posted by Zilch
    Hee, hee. That was for the OTHER Ron.

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

    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

    RC

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    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

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