Low-cost DIY practice/coffeehouse tweeterless 110 [long]

Discussion in 'Amps [BG]' started by DukeLeJeune, Jan 31, 2011.


  1. DukeLeJeune

    DukeLeJeune Only immortal for a limited time Gold Supporting Member

    Joined:
    Nov 24, 2008
    Location:
    Preston, Idaho
    Disclosures:
    Owner & designer, AudioKinesis; Auth. mfg, Big E (Home Audio only)
    For under $110 plus shipping, screws, and a bit of wire, you can put together a decent little tweeterless 110 practice/coffeehouse cab.

    The speaker you'll be using is the Eminence Basslite S2010, $74.97

    The real cost and labor saver is the enclosure, a Parts Express 10" vented subwoofer box meant for a car, exquisitely finished in classic ratfur, $28.50

    Finally you'll need a decent input jack, $1.98, along with a dish to mount it on, $4.68. No gasket needed; ratfur is self-gasketing.

    The total comes to a shade over $110, not counting shipping.

    The enclosure is about .9 cubic feet net internal volume with the speaker in place, and the port tunes the box to about 56 Hz (measured, not calculated). This tuning frequency is arguably a bit on the high side for optimum power handling before fartout, but you should be fine on low-E. On low-B you may run into fartout; if so, you can build a simple insert that will reduce the port's cross-sectional area. The port dimensions are at the link provided; if you decrease the width of the port by 4", over its entire 10.25" depth, that will lower the tuning frequency to about 48 Hz which should be fine for low B. High precision isn't required; for example, most "half-inch" plywood these days is actually 12 mm, and you can use a stack consisting of four 12mm plywood boards measuring 4" wide by 10.25" long, painted black, and wrapped on the ends with just enough black electrical tape to give a good friction fit. The stack can be centered in the port or off to one side; the tuning is the same either way, but it looks better centered.

    Most 10" woofers will have a somewhat boomy response in that little enclosure, but the Basslite S2010 doesn't. That boomy bass sounds good sometimes, but here's the problem: As you go down the low end of the scale the lowest notes sort of die off. With the Basslite S2010, there is only about 2 dB falloff of that critical first overtone as you go from low E down to low B (with the 48 Hz tuning; the difference is a little greater with the 56 Hz tuning because the low E is louder). So that's why I chose the Basslite S2010.

    Use #8 pan-head sheet metal screws, 1" long, to attach the speaker to the cab. Pre-drill 7/64" pilot holes for the screws, using the S2010's 8 screwholes as a template, and kinda hug the outer edge of the holes in the S2010's frame so that you leave lots of "meat" in the wood between the screw and the speaker cut-out. After the pilot holes have been drilled, I recommend using a toothpick to coat the inside of the holes with wood glue; this strengthens the particleboard where it needs it the most (for the screws' threads). Let the glue dry for a couple of hours before adding

    On the back of the cabinet is a little push-terminal that can accept bare wires. You might leave that in place, and just cut out an opening for the jack plate with a jigsaw.

    If you don't have a jigsaw and/or want to save a few bucks, don't get the jackplate. Instead, you're going to use that input jack as an external adaptor. Solder a couple of speaker wires to it, 18 gauge should be fine. The + wire goes to the the part that contacts the nose of the plug, and the - wire goes to the part that contacts the side of the shaft. Plug your 1/4" plug into the jack, and plug the wires coming off jack into the push-terminals.

    So you're going to want to run wires inside the box from the quarter-inch input jack and/or the little push-terminal to the speaker. You want about 18" or so, to give you a little slack to work with when you connect the speaker.

    If you want both the push-terminal and quarter-inch jack to be available, solder on two more wires, one connecting the + on the push-terminal to the + on the jack, and the other connecting -to -.

    The speaker has push-on type connectors, which you can probably find at an auto parts store. Maybe Radio Shack still carries them; take the speaker with you to make sure you get the right size. Sometimes they start out a little loose, and you can gently close 'em off just a wee bit with pliars. Overdo it, and you can usually pry 'em back open a bit with the tip of your pocketknife. Or, you can just solder the wires to the tabs on the speaker.

    But before you install the speaker, I suggest lining the inside of the cab with some 1" open-cell foam. 75% coverage is good. I think Jo Ann Fabric sells open-cell foam cut to the length you specify, and you won't need much. An 18" by 24" piece should be plenty, and you can get the cheapest the sell. Just make sure you haaaaah your breath through it; if not, it's closed-cell foam. Glue or staple in place, your choice, and keep it an inche or two away from the inner opening of the port.

    Now connect the wires to the speaker, double-checking that you're going from + to + and - to -. Install the speaker with the screws, connect your amp, and try it out.

    If you think the port-area-reduction woodstack might be a good thing, go ahead and experiment with that as well. You can make it permanent with glue and/or screws, but I suggest taping over the nearby ratfur so you don't mess it up with glue during the process.

    If you feel so inclined, you can add corners, feet, grill, and a handle. Note that the edges of the enclosure are not rounded-over, so you'll probably want to get corners that have a sharp angle.

    Now if you think you might want to add a second cab in order to have a more gig-worthy little rig, one of the cabs will need two input jacks. Wire them in parallel (like I described for the little push-terminals). The reason I don't suggest installing two jacks on both cabs is, the unused jack will be an air leak and you don't want that. Or you can get fancier air-tight connectors, taking your pick from these pages (if you decide to use Parts Express):

    quarter-inch jacks

    speakons

    dishes

    Here are the specs you can expect with the port tuning reduced to 48 Hz:

    Impedance: 8 ohms
    Power handling: 150 watts thermal
    Efficiency: 94.7 dB/1 watt, based on Thiele-Small parameters (which is how I think it should be specified)
    Low end response: -2 dB at 100 Hz, and -4.5 dB at 62 Hz (first overtone of low B). No peak in bass region. Crank in 2 dB of bass boost, and now you're -2.5 dB at 62 Hz and still don't have any peaking.
    Dimensions: 16" tall by 12" wide by 14.5" deep, not counting grill.
    Weight: About 21 pounds, before optional hardware (grill, corners, feet, handle).

    * * * *

    Take a look at the frequency response curve for the S2010:

    http://www.eminence.com/pdf/Basslite_S2010.pdf

    If I were going to use this speaker in a commercial tweeterless cab, I'd probably want to smoothe the frequency response somewhat. If you'd like for me to design a circuit to do so, let me know in a reply.

    Finally, don't ask me to sell you any of this stuff and/or do any assembly. If I were to do that, this post becomes an "ad". I'll make my nickels off the guys who can afford my expensive "boutique" cabs, but will probably never have the economies of scale that would allow me to offer competitively-priced entry-level products. Thus something like this is probably the only way I can get involved with bass players on a tight budget.
    maestrovert and Joe Louvar like this.
  2. 1n3

    1n3

    Joined:
    Sep 13, 2007
    Location:
    USA
    Very nice of you to contribute this to the TB community, Duke. Looks like something almost anyone could build.

    I'm sure you'll get some takers on this.
  3. mikeddd

    mikeddd Supporting Member

    Joined:
    Nov 12, 2009
    Location:
    San Antonio, TX
    Thank you very much, Duke! It's wonderful that you're sharing your considerable knowledge with the TB community. Many folks will build this out of curiousity for sure; I know you just pushed my DIY buttons. :) What kind of circuit/crossover do you have in mind? This little box with my Shuttle 6.0 (kept reasonably low!) would make a killer little rig for pickup gigs/garage jams. With a 4-string, would I be OK with the box's stock tuning? Don't want to launch the little voicecoil clear across my living room. :D
  4. mikeddd

    mikeddd Supporting Member

    Joined:
    Nov 12, 2009
    Location:
    San Antonio, TX
    Heck...I may buy all the stuff tonight. I'm itching to build something but with the limited tools I have on hand I've been really limited in what I can make. (I.E. No fEARful's being built at my house). I could do this!
  5. Robby Hoinsky

    Robby Hoinsky

    Joined:
    Dec 28, 2010
    Location:
    New Haven, CT
    Disclosures:
    Art of Noise Audio, fEARful™ builder
    Even better, that box is on special for $22 until the end of February.

    I'd definitely would get corners for it, mdf breaks up pretty easily. And keep it in a dry place because it will soak up humidity and swell up like a sprained ankle.

    Robby
  6. mikeddd

    mikeddd Supporting Member

    Joined:
    Nov 12, 2009
    Location:
    San Antonio, TX
    I have tons of corners already, though they are designed for rounded edges they will be infinitely better than nothing. Best to use up what you already spent money on, right? With the 3/4" mdf being used in such a small box, rigidity of the enclosure is a non-issue even with no bracing. I plan on ordering the parts tonight and doing a pictorial build post. With shipping times to me though, someone may beat me to it.
  7. mikeddd

    mikeddd Supporting Member

    Joined:
    Nov 12, 2009
    Location:
    San Antonio, TX
    Good point, GB. But wouldn't the braces take up already scarce airspace?
  8. greenboy

    greenboy

    Joined:
    Dec 18, 2000
    Location:
    remote mountain cabin Montana
    Disclosures:
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    I'd fly it the way it is unless I had actual trouble. Since Duke said "measured" response, I'd guess maybe he already has.
  9. mikeddd

    mikeddd Supporting Member

    Joined:
    Nov 12, 2009
    Location:
    San Antonio, TX
    You mean w/o the braces you describe?
  10. mikeddd

    mikeddd Supporting Member

    Joined:
    Nov 12, 2009
    Location:
    San Antonio, TX
    Dayum. PE wants $44 to ship to me (USPS). WTH? :( Kinda defeats the thought process behind "cheap little cab" just a little, huh? Screw it...I may do it anyway.
  11. mikeddd

    mikeddd Supporting Member

    Joined:
    Nov 12, 2009
    Location:
    San Antonio, TX
  12. greenboy

    greenboy

    Joined:
    Dec 18, 2000
    Location:
    remote mountain cabin Montana
    Disclosures:
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Neutrik publishes that data. I think it's on BLT and Speaker Hardware sites linked in my pages too. But I just scrounge through my trays of screws and bolts, hardly ever have to run down to the hardware store ; }
  13. Sundogue

    Sundogue

    Joined:
    Apr 26, 2001
    Location:
    Wausau, WI
    Very cool of you to post this Duke.

    You know, put together two of them or even four of them along with a 2 ohm capable head and I'd think you'd be able to do more than coffee-house gigs.

    Modular and inexpensive. Stack them, latch them together and put wheels on the bottom one, a handle on the top one and you'd have your own modular rig/cart. ;)

    Anyone know what the weight on the cabs are?
  14. mikeddd

    mikeddd Supporting Member

    Joined:
    Nov 12, 2009
    Location:
    San Antonio, TX
    Duke says 21 pounds before grill/corners/feet.
  15. Sundogue

    Sundogue

    Joined:
    Apr 26, 2001
    Location:
    Wausau, WI
    Not bad for MDF. Could be a very cool modular setup if one were to go with multiple cabs.
  16. Sundogue

    Sundogue

    Joined:
    Apr 26, 2001
    Location:
    Wausau, WI
    Who said anything about carrying? :D

    A modular, vertical 410 (or 110, 210, 310) with each cab weighing maybe 25 lbs. or so each?
  17. themarshall

    themarshall

    Joined:
    Jun 26, 2008
    Location:
    cochrane wi
    "What size nuts/bolts do you use to secure the Speakon to the jack plate?"

    I used 4-40, cause I had em. I think 6-32 would work, but my stock craps out real quick smaller than 8-32.
  18. mikeddd

    mikeddd Supporting Member

    Joined:
    Nov 12, 2009
    Location:
    San Antonio, TX
    I DID look, just for second, at the dual-driver/truckboxes...but said nahhhhhh. :ninja:

    Thanks, themarshall. Trying to find #4 bolts on PE...not doing too well. Need bolts to secure Speakon to jackplate. Went w/jackplate so I could just hack out a bigger hole around that anemic, 1/16" thick plastic terminal cup that comes on the box.
  19. Sundogue

    Sundogue

    Joined:
    Apr 26, 2001
    Location:
    Wausau, WI
    But that's what makes these more attractive. Smaller, lighter as a 110 and one could use anywhere from one to four in a modular rig.

    And one wouldn't have to "carry" them anywhere if done right. :smug:
  20. scowboy

    scowboy Supporting Member

    Joined:
    Jun 9, 2006
    Location:
    Sacramento area
    This looks like the perfect leave it in your office kind of box. Nice.

Share This Page