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Thread: full range idea

  1. #1
    Join Date: May 2008

    Location: U.S.A. Neo-Socialist Kalifornski

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    Default full range idea

    Just been thinking of building an odd animal in the speaker world.
    A mid size sealed speaker cabinet with a 8 inch full range driver and directly behind it in a push pull configuration a 10 or 12 inch passive radiator.

    Cabinet would be 2.80 cubic ft. but will using a large passive radiator allow me to use a smaller cabinet?
    Lets say 24 tall x 18 wide x14 D.

    speakers up for consideration so far.

    http://www.youtube.com/watch?v=IWDxf4Or5Vs http://www.parts-express.com/pe/show...=Bazaarvoiceps
    http://www.parts-express.com/pe/show...number=293-680
    Any body try this?
    Any feed back would be greatly useful and appreciated.

    Front and rear baffle of birch 3/4 plywood, sides 3/4 inch MDF with internal bracing.
    Last edited by goraman; 11-09-2011 at 16:36.
    Jeff :UBERTHREADKILLER

  2. #2
    Join Date: Oct 2009

    Location: Fens

    Posts: 18
    I'm Ian.

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    Would this be similar to the Lecontoure speakers?



    Amazing bass for a small standmount - Midland Audio Exchange sell them.

  3. #3
    Join Date: May 2008

    Location: Cricklewood

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    I'm ILOB.

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    Jeff why not consider going Open Baffle and getting drivers to suit you get so much more more sound per pound and you could build them not to much bigger than the diamensions you mentioned width would be 19" you can do it even less and height would depend if you just have one or two drivers
    If you interested in the idea I give you my diamensions but you can eaisly do them a lot smaller than mine
    Loves anything from Pain of Salvation to Jeff Buckley to Django to Sarasate to Surinder Sandhu to Shawn Lane to Nick Drake to Rush to Beth Hart to Kate Bush to Rodrigo Y Gabriela to The Hellecasters to Dark Sanctury to Ben Harper to Karicus to Dream Theater to Zero Hour to Al DiMeola to Larry Carlton to Derek Trucks to Govt Mule to?

    Humour: One of the few things worth taking seriously

  4. #4
    Join Date: May 2008

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    Quote Originally Posted by John View Post
    Jeff why not consider going Open Baffle and getting drivers to suit you get so much more more sound per pound and you could build them not to much bigger than the diamensions you mentioned width would be 19" you can do it even less and height would depend if you just have one or two drivers
    If you interested in the idea I give you my diamensions but you can eaisly do them a lot smaller than mine
    My only experience with open baffle was much like electrostatic panels, placement had to be at least 1 meter from the rear wall and a defuser between the wall and the speaker.

    Or imaging gets weird, Open baffles also require a very low Q much like car speakers or back loaded horns if i'm not mistaken.
    Last edited by goraman; 17-09-2011 at 19:01.
    Jeff :UBERTHREADKILLER

  5. #5
    Join Date: May 2008

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    Quote Originally Posted by Patrick Nash View Post
    Would this be similar to the Lecontoure speakers?



    Amazing bass for a small standmount - Midland Audio Exchange sell them.
    Oddly small but I really need efficiency as well as bass in a slightly larger enclosure.
    So basically I'm revisiting the imposable.

    Those speakers are only 87.5 DB.
    Last edited by goraman; 17-09-2011 at 19:17.
    Jeff :UBERTHREADKILLER

  6. #6
    Join Date: Jul 2010

    Location: North Cambs UK, Earth, Sol, Orion - Cygnus arm of galaxy

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    I'm MadeOfDeadGiantStarsThatExplodedEonsAgo.

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    Hi Jeff, you won't need a huge beast like that 12" passive radiator - take it from me All you'll need is some kind of PR that can move 2-3 times as much swept volume as the driver can.

    Calculate the driver area & then with it's Xmax the peak volume it can move & then look for something like a 10" PR. Also whatever you do make sure that the VAS of the PR is much bigger than the enclosure volume you plan to put it in.

    The reason for having the much bigger VAS is so the enclosure volume controls things & not the mechanical parameters of the PR

    If you like i can show you what happens & how the PR will mess things up big style if the VAS is smaller than the enclosure dimensions like the one you linked to. You simply won't be able to tune it fella

    Look for something with a minimum VAS of 4 times the enclosure volume...

    I'll have to take a look at the 8" driver specs as over 2ft^3 is pretty big

    E2A:- Took a look & i reckon you could do good stuff with that driver in the kind of enclosure you are thinking of. The QTS is lowish so fast response, place a PR on the back will give you some deep bass reinforcement & kind of boost it a bit as it'd be rolling off without it..

    You just need a more suitable passive radiator
    Bests, Mark



    "We must believe in free will. We have no choice" Isaac Bashevis Singer

  7. #7
    Join Date: May 2008

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    Yes geoff you ned space behind thm for them to work sorry did not know you had this as a issue If you ewre interested in the open baffle route I would of suggsted other drivers
    Loves anything from Pain of Salvation to Jeff Buckley to Django to Sarasate to Surinder Sandhu to Shawn Lane to Nick Drake to Rush to Beth Hart to Kate Bush to Rodrigo Y Gabriela to The Hellecasters to Dark Sanctury to Ben Harper to Karicus to Dream Theater to Zero Hour to Al DiMeola to Larry Carlton to Derek Trucks to Govt Mule to?

    Humour: One of the few things worth taking seriously

  8. #8
    Join Date: Jul 2010

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    Had a look at the PRs on that site Jeff. There is a Dayton 10" which would do the trick, but it's VAS is still not much more than the enclosure size you are planning on. However i reckon the 12" might be a good one

    The thing is though is this, it has a pretty low resonance frequency so you may find that you simply won't be able to get the thing to resonate at a high enough frequency.

    However if you use 2 of these 10" daytons in each enclosure i reckon you'll get the resonance frequency up above where you want it & can then add mass to tune it lower. Also using 2 of them the combined VAS will be much higher & the enclosure air volume will predominate much more, rather than the suspensions of the PRs. Two of these is still way cheaper than one of those things you were originally linking to
    Bests, Mark



    "We must believe in free will. We have no choice" Isaac Bashevis Singer

  9. #9
    Join Date: May 2008

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    Quote Originally Posted by Reid Malenfant View Post
    Had a look at the PRs on that site Jeff. There is a Dayton 10" which would do the trick, but it's VAS is still not much more than the enclosure size you are planning on. However i reckon the 12" might be a good one

    The thing is though is this, it has a pretty low resonance frequency so you may find that you simply won't be able to get the thing to resonate at a high enough frequency.

    However if you use 2 of these 10" daytons in each enclosure i reckon you'll get the resonance frequency up above where you want it & can then add mass to tune it lower. Also using 2 of them the combined VAS will be much higher & the enclosure air volume will predominate much more, rather than the suspensions of the PRs. Two of these is still way cheaper than one of those things you were originally linking to
    Wow! I 'm now sure I have no idea what the hell I'm doing.
    I think I have to learn alot more about speaker physics.
    Jeff :UBERTHREADKILLER

  10. #10
    Join Date: Jul 2010

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    Quote Originally Posted by goraman View Post
    Wow! I 'm now sure I have no idea what the hell I'm doing.
    I think I have to learn alot more about speaker physics.
    I guess it's a good job you know someone that's been designing them for 30 years then innit

    I have no idea why damn near every one of those PRs has such a miniscule VAS It just doesn't make sense at the end of the day

    But i reckon with a bit of messing about you can get something close to what you want Jeff.

    By the way, take a look about over your side of the pond & see what other 8", 10" or 12" PRs you can find & link me to them. There should be stuff with bigger VAS out there & this would be even better. Like i say, i can show you why if you like
    Bests, Mark



    "We must believe in free will. We have no choice" Isaac Bashevis Singer

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