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building a 4x10 cabinet

Discussion in 'Amps and Cabs [BG]' started by bassguitar, Apr 25, 2005.

  1. I've ordered 4 Eminence bp102 speakers (200 W), and a piezo horn. I'm going to wire them like this http://colomar.com/Shavano/4x12wiring4.gif with an Lpad on the tweeter, but I'm not totally sure where to put it in.

    I'm trying to figure out how big to make the cabinet. I've tried WinISD, but I don't think I'm doing it right. It's giving me a box that's 46" high. That seems way too big for a 4x10. An ampeg I've looked at is 27x24x18 ported.

    I'm going to make it with 3/4" ply - birch if I can find it unless others have better ideas.

    Also - what about baffles - how do they go in? Am I in over my head?!?!

    Thanks to speddling for pointing me here!
  2. herndonbassist

    herndonbassist Low Down Thumper Supporting Member

    Apr 7, 2005
    Herndon, VA - NoVa
    You should try messing around with the porting of the cabinet, that will help you reduce the size. I've always cheated and either copied an existing cabinet, or I've gone with an open back design (infinite baffle). You'll definitely want baffles, but that's also to help with the structural integrity.

    My suggestion is to find someone who has a cabinet that you are trying to replicate and see how it is constructed, and go from there. There might be a TB'er or 2 on here who might help you out.
  3. Funkengrooven

    Funkengrooven Turn it down? You gotta be nuts!!

    The minimum size is going to be determined by how you have the speakers

    is the normal method for a 4x10 although staggered is also used

    with the above pattern you could make the cabinet 24 x 24 for the front panel and that would make each speaker 1 inch from the other and 1 inch from the sides.

    front mounted speaker holes are usually 9 inches and some in diameter, the speaker determines that. the depth of the cabinet is up to you, the deeper it is the more air in the cabinet and the greater the cone excursion.
    The bigger the cabinet the more boom. a smaller cabinet will sound tighter. So therefore a cabinet that is 18 inches deep will sound one way and a cabinet that is 10 inches deep will sound different. Experiment..

    check out some cabinets that are already on the market and build to match.

    A wise engineer once told me " the best way to get your engineering done quickly is to have some body else do it"

    winISD assumes that you are building a standard rectangular cabinet, in this case you are not so that does not apply.

    and you will only need winISD if you decide to port the cabinet
  4. Thanks for the prompt replys.

    It's going to be like this with the tweeter in the middle.
    * *
    * *

    If I build it sealed, won't that take away some of the bottom end?
  5. That's what I'm trying to get out of you guys!!!!! :bassist:
  6. Funkengrooven

    Funkengrooven Turn it down? You gotta be nuts!!

    when you seal up a cabinet the tone comes from the cabinet size and how much power you shove into it.
    witness the SVT, completely sealed. 300 watts...how much bottom do you have there??? shake the freakin stage with no sweat.
  7. r379


    Jul 28, 2004
    Dallas, Texas
    What kind of tone are you looking for? If you're not a slapper/popper you might be able to get by without a tweeter given that the B102 speakers have a`whizzer cone. As I recall, the frequency response on those things runs up to around 9 Khz.
  8. You're right, but that was a typo on my part - they're BP102's.
  9. r379


    Jul 28, 2004
    Dallas, Texas
    Nope, it was a misread on my part. You wrote bp102; I just managed to overlook the "p" part. Being old (and in the way) I could probably get by without the tweeter even with the BP102. I like that old tone.
  10. ESP-LTD


    Sep 9, 2001
    I believe the BP-102 wants to run in a pretty big box; like 2' per driver. That 46" figure may have been right on. It will have plenty of lows, but not much loud and it will be big.
  11. Some speakers want to use a larger volume to be more efficiant- I found this while designing a 2x12 cabinet.

    The Eminenece Beta 12" Speaker constantly brought up a huge cab, even when only using one the cab was massive. 265L of volume was requireed for each cone... Thats alot.

    The Delta 12" had a more respecatble 100L or so of Volume per cone.

    Of course you can change these numbers, but if you use winSID you'll see what changing the numbers does in terms of responce, range etc...
  12. msquared


    Sep 19, 2004
    Kansas City
    I'd like to offer the suggestion that you build two 2x10s instead of a single 4x10. It's easier to transport. You can build the first 2x10 without a tweeter and see if you actually need a tweeter in the other one. And best of all, you have the option of setting it up like:

    * *
    * *

    or else


    depending on whether you want it to look better or sound better.
  13. Petebass


    Dec 22, 2002
    QLD Australia
    I'm at work so i don't have my speaker data with me. From memory the BP102 has a rather low sensitivity rating in favour of low end response. This means it'll need a very healthy dose of watts to get this cab loud enough for a band situation. What sort of amp are you planning to use with it?
  14. The BP102 requires a minimum of 2.19 cubic feet, each, for correct BB4 tuning at 40 Hz.

    Using a bottom slot port, and 0.75" material with a 1.5" baffle recess, this yields a cabinet of 44H x 27W x 17.5D inches, net internal volume of 8.7 cubic feet.

    Made from Baltic Birch, cab and drivers will weigh 120 pounds. Weight of handles and grille is additional.

    Too big.

    Consider building a pair of 2x10 instead... easier to haul around.

    In this tuning, you can expect a maximum SPL (each) of 109 at 100 watts, at 43 Hz, before the drivers exceed Xmax. Running a pair of 2x10 on a dual-channel power amp at 4 ohms/200 watts per channel, you can expect 115 ~ 121 dB maximum from the combined output of all 4 drivers. This driver is out of gas above 2,000 Hz so a tweeter is required.
  15. I'm thinking about a Yorkville xs400H. Maybe the xs800H if I can afford it.

    I've been using a borrowed xs400 combo (15"), and I quite like the sound especially with my Boss MEB50.

    The 2 2x10's sounds like a good idea. Not sure about how the baffles go in though (aside from the slot vent that's pretty self explanitory.)
  16. WinISD gives me 18x29x10 sealed for 2 drivers. Looks like I'll do 2 boxes that size - one with a tweeter one without. Is that it just a box with the speakers in it or do they need baffles around the speakers? Do i put in 3/4" padding around the whole box or just leave it empty?

    With a vent it looks louder around 40hz, and puts it at 23x37x13 with a 4.5 x 4.5 x 2 vent. Could it be 1 x 9 x 2.5 with the same result?

    Sorry I've got so many questions, but I'm new to this!
  17. The BP102 has an EBP of 80, making it halfway between sealed (50) and vented (100).

    The B2 sealed alignment offers the most flat response, with an F3 point of 61 Hz. The required volume for B2 is 1.66 cubic feet, each.

    I'd be doing this driver as a 2x10, vented in BB4 as mentioned above.
  18. So here's what I've decided if anybody gives a rats ass:
    I'm going to build it 4 x 10 minus the tweeter (I can always put it in later). 48"x28"x18" front ported 4.5 x 4.5 x 2.5 using the eminence bp102 drivers. I'm using 3/4" ply for the sides and 5/8 for the top and bottom, possible trimmed out with oak, and 1x1 pine for inside bracing. It should turn out well enough that I can stain it, and not have to cover it with carpet or vinyl. Recessed wheels and handles. T-nuts on all the speakers and handles. Front baffle will look like so:


    It's gonna be a pig but it won't be moved that often.

    I've ordered a Yorkville xs800H for a great price that should run 8ohms at about 600W.

    Should be constructed this Saturday. Can't wait!
  19. So the box is done. Put the last coat on it this morning. I'm going to wire it tonite and put it all together if I've got time.

    What do you peeps think - should I wire it 2 ohms, or 8 ohms? The amp can handle a min load of 2 ohms, and I probably won't be putting another cab on this amp anytime soon. It's rated 800W at 2 ohms, and about 600W at 8 ohms.
  20. brother bean

    brother bean

    May 23, 2003
    If the box deminsions were 28x25x17 with 50sq inches of port area, what would the specs be? How much would dampening material help the spl and low usable freq?

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