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Designing cabs for a pair of eminence basslite S2012s

Discussion in 'Amps and Cabs [BG]' started by micahwc, Oct 6, 2017.


  1. Greetings,

    I have a single eminence basslight S2012 and I love it. The cab I am currently using has issues so I'd like to replace it. I'd like to run 2 S2012s at 4 ohms to pair with my Fender Rumble 500.

    Sorry to ramble; my question is about the size of the speaker enclosure. Eminence recommends 1.15 cubic feet for a sealed enclosure for 1 S2012.
    The DIYaudioandvideo.com speaker enclosure volume calculator recommends 2.74 cubic feet. Should I go with the larger enclosure or eminences recommendations?
     
    Last edited: Oct 6, 2017
  2. BadExample

    BadExample

    Jan 21, 2016
    Injiana
    Larger sealed cab will give louder bass, at the expense of tightness, or clear undestorted lows.

    Smaller will give tight bass, more controlled low end, at the expense of loudness.

    What is your goal?
     
  3. Ampslut

    Ampslut

    May 15, 2017
    basscooker and BadExample like this.
  4. I've actually already got plans for an Omni 15 tall boy but I'm going to wait on that for a bit.

    I have tools, a table saw, lots of 1/2 birch ply, and some wood working experience, and 1 s2012 already.

    Almost all my gigging is done through a house system, so whatever I make will be used 99% of the time at home.
     
  5. I think I'll just go with the 1.15cf volume on both for now since it will likely be used at home 99% of the time. The only places I would use it without PA support would be small venues like coffee shops, upscale "quiet" bars, etc.
     
  6. seamonkey

    seamonkey

    Aug 6, 2004
    What are your current "issues"?

    Model it in the software.
    Leave extra room on the inside to increase bracing if it needs it.
    Some 3d CAD software can model stresses on cabinets.
    Before building it then listen to the response by duplicating it with an EQ plugin.
    Build a prototype in mdf, see if it does match what your predicted in the model.
    Build the Plywood prototype - check that is doesn't run in the same "issues" as your current plywood bass cabinet.
     
    b-b-b-bass likes this.
  7. AstroSonic

    AstroSonic Supporting Member

    Dec 10, 2009
    rural New Mexico
    I use S2012's in 2.4 cf (each). Tuned to 41 Hz, bass is deep and weighty. Bass is a little less extended but tighter when tuned to about 48 Hz. Tightness with the higher tuning sounds a lot like a sealed cab, but with obviously greater bass extension.
     
  8. I've decided to use the emenience recommended volume for a small sealed cab, but doubled for two speakers. I plan on wiring them in series, which will run 350 watts out of my amp so as to not damage speakers which are only rated 300 watts program power each.

    With 350 watts and 97 efficiency these should be able to get plenty loud. 95 db at 100 feet if my numbers are correct and even more if I put the cab near a wall or corner.

    I'm using DIYaudioandvideo.com's speaker enclosure dimension calculator to determine my dimensions.

    Thanks for the help.
     
  9. AstroSonic

    AstroSonic Supporting Member

    Dec 10, 2009
    rural New Mexico
    Two 8 ohm drivers, like the S2012's, wired in series yields a load of 16 ohms. Two in parallel yields 4 ohms. Two 212 cabs, internally wired in parallel for 4 ohms, yields a total of 8 ohms. You can safely use a 212, 4 ohm cab with an amplifier that exceeds the 600w program rating of the cab, provided that you listen to the sound for signs of distress, and occasionally check on once excursion. It's really not that difficult. after a while this will be second nature.
     
  10. BadExample

    BadExample

    Jan 21, 2016
    Injiana
    ^^^ This. Although the smaller the sealed cab, the less likely, you'll probably hit mechanical limits before wattage limit. In fact the plans say:

    Displacement Limited to 125 Watts. Slow Roll-off.
    Great for Ultra Clean Bass.
    https://www.parts-express.com/pedocs/more-info/290-518-eminence-basslite-s2012-more-info.pdf

    Double that for 2, 250 W mecanical limit. So as astro says, just listen to it. Don't let the 250 W figure scare you. If you look at the SPL cart for a single. Add a handfull of db, you'll go deaf before the cab goes mute.

    Where you could get in trouble is if you try to kick up the deep bass with eq. I'd guess + 3db @ 100Hz and don't boost below that. 5.2mm Xmax, 9.8mm Xlim, I think you should hear some noise before hitting the crash burn point of Xlim. That is unless you pop it real hard, like plugging in hot, or if pedal distortion is limiting your ability to hear speaker distortion.
     
  11. So running them in parallel with the amp at 500 watts won't be a problem provided I use them sanely?
     
  12. AstroSonic

    AstroSonic Supporting Member

    Dec 10, 2009
    rural New Mexico
    Laws of physics apply: 500w amp and 600w (program) cab should be fine for the thermal limit.

    The displacement limit is lower, but you should be just fine provided that you heed the above advice regarding bass boosting. The fundamental of a low bass note typically constitutes around 20% of the note's power - a 100w low E has around 20w at 41 Hz, and a similar amount in the second harmonic (82 Hz). So a 500w note will have around 100w in the fundamental. So, the 125w displacement limit is adequate. However, a mild (3db) bass boost will double the amount of power in the low bass frequencies, causing the displacement limit to be substantially exceeded. The good news is that there will be audible sounds of distress well before that happens. An adjustable high pass filter would also help ensure the health of your cab.
     
    John Chambliss and BadExample like this.
  13. BadExample

    BadExample

    Jan 21, 2016
    Injiana
    A little insane is good. A lot gets you funny looks and dead cabs :D I really think in your home you's be fine if you don't go crazy trying to boost 100 Hz or lower. If you have an unlabeled as far as the frequency goes "Bass" knob, it may be good to discover what frequency that is centered. I don't think it's the norm, but mine is @50 Hz. Then one of the semi-perametrics goes as low as 50 Hz, and a graphic eq that's 50Hz (plus another @ 80Hz, and 125 Hz). All +/- 12 db. I would expect careless use could result in damage to many cabs rated for high wattage.
     
  14. hombass

    hombass

    Jul 5, 2012
    If i may recfomend, use a computer program that accepts the manufacturers thiele-small parameters for the drivers you want to use and that allows you to select a center frquency. I had a pro cabinet maker build my 2x10 cab with a center freq of 80hz. Based on two eminece Kappa pro 10's. With shelf port. It is actually 2 1x10's in the same cab. It will reproduce very well down to 20hz. (Makes your vision blur) and has an amazing range without a tweeter. You know youve got a great cabinet when the drummer and guitar player want you to bring it to every gig! Lool
     
  15. hombass

    hombass

    Jul 5, 2012
    To reiterate, i think the computer programs, vs. just a square foot recommendation from the driver manufacturer, is worth the effort.
     
    micahwc likes this.
  16. Speaking of BFM, the 2012 is recommended for the Jack 12.
     

  17. I've run them through a program and the reason I originally asked the question here was because there was quite a large difference between what the program recommended for a sealed cab and what the manufacturer recommended. So, all other factors being equal, you would go with what a program outputs over the manufacturers recomendations?
     
  18. hombass

    hombass

    Jul 5, 2012
    Did you input all the thiele small parameters for the drivers? I think the computer program would be correct, but my knowlege of closed cabs is limited. Ive always perferred the sound of ported enclosures. Im not sure, there are many many experts on here way above my level. Ive had good luck both ways. I went by a cubic foot volume suggested by jbl for a cab for a 15" e 120. It works, but i do wonder what it wouldve sounded like with a computer program design. The shelf port2x10 cab i have that was built using a program, with a center frequency of 80hz. is an absolute monster for gorgeous tone and eye blurring power. Best cab i own. Im not sure maybe talk to the manufacturer some more. The drivers for my 2x10 are eminence kappa pro 10's. I bought them from US Speaker in new jersey. They also ran the numbers for the cab design through a program for me. Good guys to talk with.
     
    micahwc likes this.
  19. AstroSonic

    AstroSonic Supporting Member

    Dec 10, 2009
    rural New Mexico
    The 'factory recommendations' are really just examples of box/driver combinations with rather broad recommended applications (bass guitar, keyboard, PA, etc.). The more uses a driver is suitable for, the more drivers they are likely to sell. A much wider range of cab designs is possible. You can use speaker design software, just as they did. If you haven't done much of this before, it's a good idea to run the design by those with experience here on TB.
     
  20. I imputed all of the thiele small parameters and got a recommended sealed volume of 5.48 feet cubed for the pair of speakers.

    I started putting a box together using 1/2" birch. Dimensions are 16x39x18 with 3/4" battens, giving a total volume of 5.52 feet cubed before adding bracing. Box is held together with 1 inch dry wall screws while the pl premium dries.

    I only had one piece of ply on hand long enough to cut a 16x39" baffle, so the sides are made from two pieces joined with a reinforced butt joint, which was then supported by a glue and screw of a hardwood plate on the interior side of the joint line for each side.

    Left and right side, top and bottom are also supported by a 3/4" batten on the inside of the baffle. Sides, top and bottom are screwed and glued to both the batten and the baffle.

    Interior seems are all sealed with PL Premium which was smoothed into the seems with a latex glove covered finger. All the screw heads will be sealed as well before I'm done. Butt joint for the sides is sealed on the outside and on all four sides of the reinforcement plate in the inside.

    I'm working through the back currently, which I haven't cut out yet.

    I picked up a pair of 1" thick hardwood dowels to use for bracing.
     
    BadExample and hombass like this.

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