DIY Building a 6x10 nonported light cab

Discussion in 'Amps and Cabs [BG]' started by Mark Joe, Jul 7, 2008.

  1. Mark Joe

    Mark Joe

    Apr 8, 2008
    Frederick MD
    I am borrowing a friend's Acoustic 6x10 keyboard cabinet;
    I am attempting to build my own because I love the tone of
    the cabinet so much. Any advice is greatly appreciated.

    First, I am an engineer but not an acoustic engineer;
    I don't quite understand why some cabs are ported and some are not.

    This particular cab is 36" tall, only 12" deep, 24" wide; the
    drivers sit about 2 1/2" back from the face of the amp. It is made of
    3/4 plywood.

    I play through a GK 400RB amp, with the treble fairly cranked.
    This together with the cab seems to give a very middy-to-high
    distorted but warm sound that cuts thru. I play indie punk styles.

    Any advice on design for a cab of this type would be great.
    Materials, how to brace if at all etc. Should I use 1/2 plywood for
    a 6x10 cabinet?


  2. parsons


    Feb 22, 2008
    Baltic birch plywood is used in many cabs.
  3. Mark Joe

    Mark Joe

    Apr 8, 2008
    Frederick MD
    How does one go about bracing, if 1/2 inch is used, or is 1/2 inch
    baltic birch unadvisable for such a large cab?

    The cab I am using as a design basis (3/4" plywood) has one brace, mounted vertically up the middle, and braces the front to the back. It is centered, about 18" tall, with a 9" gap at the top and bottom.

    Are there other / additional / better ways to brace? Thanks much!
  4. Rick Auricchio

    Rick Auricchio Registered Bass Offender Supporting Member

    Mark, you first have to research the speakers themselves, since you're unlikely to find the same ones Acoustic used for that cab. The drivers you use will probably have different cab requirements.

    Using the detailed speaker specs, one then designs the cabinet. It's important to get the cab interior volume correct, taking into account the space used by the braces and the drivers themselves.

    You can't just build a cab, put in some drivers, and get something good. Without a proper design, it's a crapshoot.

    As for the wood, Baltic birch is very solid with few or no voids in the plies, so it's strong. Another wood called Arauco plywood is good; it's lighter and costs 1/3 less. You can find that at most Lowe's stores.
  5. Mark Joe

    Mark Joe

    Apr 8, 2008
    Frederick MD
    yes, I was wondering that. great advice. looking at other threads about cab design, I think that must be true. Yes, I'm sure the wrong speakers wouldn't get the same sound.

    thanks very much for confirming something I suspected! cool.
  6. bottomend!

    bottomend! Gold Supporting Member Supporting Member

    Oct 23, 2007
    I"m pretty sure the Acoustic 104 is NOT braced. I should know this for sure because I own two of them and I have opened them up on occasion but I cant remember! It's one of my all time favorite cabs and it would be cool to see how you're turns out!
  7. Mark Joe

    Mark Joe

    Apr 8, 2008
    Frederick MD
    yes, mine (1976) does have one brace, but I'm not sure if it is original though or not. It has some writing on it which makes me suspect it might have been added after market. The brace is from front to back, half the height of the cabinet, centered top-to-bottom. Interested to find out if this is like your cabs or not. I am trying to find a source for the eminence drivers or specs on them through some vintage speaker folks... when I find out, I'll post their specs.. I don't even know how many watts the speakers or the whole cab is...

    but I figure the more speakers the better; the speaker breakup is great on this cab.

    thanks :)
  8. bottomend!

    bottomend! Gold Supporting Member Supporting Member

    Oct 23, 2007
    I just checked one of my 104s and there is a brace midway ( top to bottom) running from side to side. It doesn't fully contact the front baffle but it is attached to both sides and the rear. It's probably about 5 inches deep.
  9. CrackBass


    Aug 10, 2004
    you can build a 610 from 1/2". it will be harder to build and take a little more planning but imo it would be worth it. brace it well. i would use 2" strips of ply (or maby 3" for larger spans). glue them in and put enough of them in so no more than 8-12" is without bracing.

    as far as dimensions, you need to know what speaker you will use first. go to and they have cabinet designs for all their speakers. this will give you a good idea. for a light 610 i would probably start looking at the basslite s2010. sealed cabs have never been my thing so i never saw if eminence even reccomends a sealed configuration with that one, but i'm thinking it will work.

    oh when bracing pay special attention to the baffle cause with six drivers hanging off it, it's going to have a tendancy to flex. and tie the baffle and the back together with a brace roughly in the center.
  10. i'd download win isd and model some speakers to see what kind of frequency response they have in different cabs. some speakers work better in sealed cabs or ported than others. see what they look like modeled in both at different volumes and tunings. a good tool to give you a good idea of what you will come out with, even if you dont know much about it.
  11. I would also be interested in the specs of this DIY cab, I've been considering building one myself.
  12. I have a question, when choosing speakers for a DIY sealed 6x10 bass cabinet, how would the ohms work out?
  13. As speakers tend to come in impedances that are powers of 2, making something with 6 drivers comes out a little weird.

    Your (most likely to be reasonable) options for wiring are:

    A: all 6 in parallel

    B: 3 sets of series pairs wired up in parallel

    C: 2 sets of 3 speakers wired in series, all wired up in parallel.

    for total impedances of:

    option A gives 1/6th the impedance of each driver
    option B gives 2/3rds the impedance of each driver
    option C gives 3/2ths the impedance of each driver.


    if you want a 4 or 8 ohm box you are going to need to find some not so common stuff:

    you can get 4 ohms with 24, 6 or 2 and 2/3 ohm drivers
    you can get 8 ohms with 48, 12 or 5 and 1/3 ohm drivers.

    Of those I suspect 6, 12, or 24 ohm speakers would be easiest to find. The way I would look would be to figure out what the (most likely Eminence) OEM speakers are in some commercial 6x10 cabs and try to track some of those down.
  14. Rick Auricchio

    Rick Auricchio Registered Bass Offender Supporting Member

    With six 8-ohm drivers (the most common impedance you'll find), you're going to get about 5.3 ohms.

    Each pair is wired in series, thus there are three sets of 16-ohm pairs. Those pairs are wired in parallel, and you've got 5.33 ohms.
  15. So with all 6 running parallel with 16 ohm speakers, would the resulting total ohms load be 2 ohms? If so, anyone know where to find 16 ohm bass speakers?

    P.S. My apologizes to the OP, I didn't mean to take over your thread! But it just so happens that I'm going through the same project myself.
  16. no.

    one more time:

  17. Mark Joe

    Mark Joe

    Apr 8, 2008
    Frederick MD
    I took apart my acoustic 104 today,
    each driver is 24 (or 25 ohms) and they are wired all in parallel,
    so the cab impedance is just over 4 ohms Its actually 5.3 ohms so I'm checking each driver, but thats probably due to the wiring... maybe something shook loose

    I need to get this cab running at around 8 ohms,
    so I am thinking of rewiring it to parallel 24 ohms (4 drivers) with 12 ohms (2 of the drivers), which gives 8 ohms total impedance. but it wont be balanced amongst all the speakers (two of them will be twice as loud as four of them), but thats ok, I just dont want to blow up my GK 400RB amp by running a load less than 4 ohms (I am parallelling with an ampeg 8 ohm cab)
  18. DC ohm reading is not the same as the "actual" resistance of the speaker. 8 ohm speakers usually will read between 5-6 ohms on a DC scale.

    Look for writing on the speaker frame to see what the impedance is.
  19. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    If you are planning on replicating the tone of a beloved cab, as I once did, I strongly suggest measuring its low frequency response curve. I have some instructions and tools at my little web page. This eliminates a lot of false assumptions about how the response curve shown in WinISD relates to how your design will sound.

    Also, my 12" design article is an example of a ported speaker intended to mimic a sealed cab.

    While we're at it, don't assume you need to use 10" drivers to get your desired results. My view is that there are limited options for DIY'ers in terms of what drivers we can buy for a tolerable price, and opening up your options gives you... more options.
  20. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    If that 24 ohms is DC resistance that indicates 32 ohm drivers.

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