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DIY Furniture Subwoofer

Discussion in 'AV Stands, Cabinets, Seating & Furniture' started by steveTHX, Jan 26, 2004.

  1. steveTHX

    steveTHX
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    Well one day I was thinking how to put an 18inch sub in the living room without having a problem with my mum. So a thought came to my mind watching that piece of furniture sitting in the corner with nothing in it. My occupation is an audio engineer and had lying around from a night club that didn’t go that well one B&C 18inch loudspeaker. I measured the bottom face of the furniture and the 18inch fitted perfectly. I have it powered by a Caudio 3001 professional amp rated at 2x650(4ohms) driven by the sub pre out of my Yamaha DSP-A2, and guys I can say one thing, IT REALLY ROCKS….

    photo 1 :
    http://briefcase.pathfinder.gr/download/stevegr/18061/209302/0/sub1.jpg

    photo2 :
    http://briefcase.pathfinder.gr/download/stevegr/18061/209303/0/sub2.jpg

    photo 3 :
    http://briefcase.pathfinder.gr/download/stevegr/18061/209304/0/sub3.jpg

    photo 3.1 :
    http://briefcase.pathfinder.gr/download/stevegr/18061/209318/0/sub+03.1.jpg

    photo4 :
    http://briefcase.pathfinder.gr/download/stevegr/18061/209305/0/sub4.jpg

    photo 5 :
    http://briefcase.pathfinder.gr/download/stevegr/18061/209306/0/sub5..jpg

    photo 6 :
    http://briefcase.pathfinder.gr/download/stevegr/18061/209307/0/sub6..jpg

    photo 7 :
    http://briefcase.pathfinder.gr/download/stevegr/18061/209308/0/sub7..jpg

    photo 8 :
    http://briefcase.pathfinder.gr/download/stevegr/18061/209309/0/sub8..jpg

    photo 9 :
    http://briefcase.pathfinder.gr/download/stevegr/18061/209310/0/sub9..jpg

    photo 10 :
    http://briefcase.pathfinder.gr/download/stevegr/18061/209311/0/sub10..jpg

    photo 11 :
    http://briefcase.pathfinder.gr/download/stevegr/18061/209312/0/sub11..jpg

    photo 12 :
    http://briefcase.pathfinder.gr/download/stevegr/18061/209313/0/sub12..jpg

    photo 13 :
    http://briefcase.pathfinder.gr/download/stevegr/18061/209314/0/sub13..jpg

    photo 14 :
    http://briefcase.pathfinder.gr/download/stevegr/18061/209315/0/sub14..jpg

    photo 15 :
    http://briefcase.pathfinder.gr/download/stevegr/18061/209316/0/sub15..jpg

    photo 16 :
    http://briefcase.pathfinder.gr/download/stevegr/18061/209317/0/sub16..jpg
     
  2. WBC

    WBC
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    That looks the nutz!!

    :smashin: :smashin: :smashin: :smashin:


    Stace :D
     
  3. steveTHX

    steveTHX
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    thanks mate..:smashin:
     
  4. ReTrO

    ReTrO
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    My god, man!

    What have you got the ports tuned to? (Or are they something else that looks like ports?)

    How does it sound?
     
  5. steveTHX

    steveTHX
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    the [ports are tuned at 45hz, and it sounds mad..129.4db SPL at 50hz driven at 595wattsRMS...At first my next door neighbour was complaining from the bass that was PASSING through the walls of my house to his, so one day i called him over and we watched 2 fast 2 furious and ever since then every time we meat he asks me : Steve when are we going to watch a movie??!!!!! at this point I should say that the only time that the sub is on while watching a movie is when my mum isn’t home..!!!! CRAZY:rotfl:
     
  6. GaryG

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    Very nice!

    Do you have the T/S parameters for that driver?
     
  7. MuFu

    MuFu
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    Does your mum know what you've done with her £3000 antique table? :D

    Genius, mate. Genius...

    MuFu.

    P.S. Weren't you tempted to go for a smaller driver?
     
  8. steveTHX

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    Thanks guys for your comments and yes I do have the T/S parameters and I will post them very soon. at first I was going to install a 15inch Magnat car sub
    ( http://briefcase.pathfinder.gr/download/stevegr/18061/209864/0/sub12.jpg ) and which I did and it didn’t play very well, so I went for the 18inch. Well my mother did know I was going to do this and she wasn’t very positive about it so I assured her that I wasn’t going to modify the outside of the table so she said ok…now I’m working on a centre speaker with Dynaudio drivers and will post pic’s soon..
     
  9. steveTHX

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  10. steveTHX

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    This is what was written about the B&C speaker I used…

    The most powerful 18" in our product range, 2000 W continuous program power handling, defines the "state of the art" about LF reproduction. A four inch copper wire voice coil with very high thermal capability and a ventilated magnet assembly allows a low power compression. A very low distortion figure is obtained using a double spider design and dual demodulation rings in the magnetic path. Proprietary water-proof cone treatment for safe use in adverse climatic conditions.

    link is here : http://www.thielesmall.com/database.asp#
     
  11. GaryG

    GaryG
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    SteveTHX

    I ran a few sims with the T/S parameters for that driver, the f3 point was well into the 40+ hz region. I presume you are using a lot equalisation to get the low frequencies?
     
  12. steveTHX

    steveTHX
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    Well no I’m not using any equalization, the secret is my amp which can drive the driver very low heaps of power. The amp is bridged and outputs 1200wrms that can power the driver at 45hz very hard without any power shortages.
     
  13. Nimby

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    Hi,
    Interesting project.

    Can anyone clarify whether the design is truly optimised for this unit/size of cabinet? There was some discussion about the porting. Is it really one-note bass at 40-45Hz or was that a slight exageration?

    Despite some searching I haven't yet found any box design software online that doesn't use Excel. Using the basic formulæ and a hand calculator is a bit slow. :(

    NIMBY
     
  14. Nimby

    Nimby
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    Okay, let me try and make it simpler. :)

    Would tuning the port(s) to a lower frequency widen and flatten the frequency response?

    Would anyone like to put up a graph of the expected frequency response as it is now and compared with tuning to (say) 20Hz?

    NIMBY
     
  15. GaryG

    GaryG
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  16. Nimby

    Nimby
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    Hi,

    Excellent. Thanks very much Gary. Great fun.

    I was just about to crank up my old BBC to write my own Basic software using the formulæ on Subwoofers DIY.

    WinISD doesn't handle 6th order <series> bandpass.

    Are there any formulæ knocking about for these particular boxes?


    Best regards
    NIMBY
     
  17. GaryG

    GaryG
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    You're going to need that Excel spreadsheet!

    http://www.diysubwoofers.org/bnd/bandpass.zip
     
  18. Nimby

    Nimby
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    Hi,
    Thanks anyway Gary. But I'd already found and downloaded this one.

    I can't use Excel as I don't have it on my (XP Home) computer. Last time I looked it was about 200 quid for Excel. I found a number of "free" design software packages using Excel during my online search. But sadly the Excel stuff must remain only a distant dream.

    Thanks for the kind thought. Very much appreciated. :)

    Best regards

    NIMBY
     
  19. Nimby

    Nimby
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    Steve or Gary,

    Just for fun & to find to my way around this software I've entered the B & C 18" parameters into WinISD Pro.

    Can I ask what the internal dimensions were for the cabinet?

    Looks like 2 small ports in one of the images? What size were these please?

    Thanks

    NIMBY :)
     
  20. GaryG

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    I can't help you with the cabinet volume but Steve said the ports were tuned to 45hz.
     

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