Vertical, sealed, 2x12 build?

Discussion in 'Amps [BG]' started by andrklet, Feb 6, 2014.


  1. andrklet

    andrklet Guest

    In my search for a portable, medium duty, inexpencive, midrange puncy cab. I have decided, the ultimate configuration would be a vertical, sealed 2x12. Not many to choose from out there (why??), so I´ve started toying with the idea of building one. I´ve seen it debated here and I´ve heard, among others, TB-member kringle77´s youtube demos. I like:bassist:

    Anyhow, i can easily get hold of 2 Eminence B12a, at a good price.:
    Nominal Impedance 8 ohms
    Power Rating Watts 250 W / Music Program 500 W
    Resonance 47 Hz
    Usable Frequency Range 43 Hz - 3.8 kHz
    Sensitivity 98

    Which I so far understand will do a decent job? The build should´t be to problematic as I´m used to doing plenty of stuff I´ve never done before :meh:. But there is a few questions coming up. Do I want to build two separate (0.9-1.25 cu.ft.) compartments, or keep it open between the two? And why so?

    I will probably be running this with an Ampeg PF350 or perhaps going all out wit the PF800. If I succeed I´ll probably build another. Ideally I want to be able to choose between running the cabs at 4 or 8 ohms. Silly question, can I wire them using two 1/4" jacks, one in series and one in parallel? Is it that simple?
  2. BassikLee

    BassikLee

    Joined:
    Feb 13, 2004
    Location:
    Deltona, FL
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    Owner: Brevard Sound Systems
    I'd do two separate chambers. Many reasons.

    As for your wiring, your options for that cab would be 4 ohms or 16 ohms. Can't get 8 with two 8 ohm drivers, no matter what you do. Also can't have them wired in series and in parallel at the same time. You will need a switch.

    Good luck with your build. I'm toying with a very similar build
  3. andrklet

    andrklet Guest

    Ah, there you go. I´m new to this, as you obviously can see :) That leaves me with the option of getting 16 ohm drivers for a 8 ohm cab, or 8 ohm drivers for a 4 ohm cab as the only usable option. Thanks!
  4. jwindham

    jwindham Supporting Member

    Joined:
    Sep 17, 2006
    Location:
    New Orleans, La
    I actually tried out a sealed 212 cab with Beta 12a's (built by LDS, Kringle77 design). Don did a beautiful job on the build, as always, but I felt it was a tad unbalanced. Could have broken it in more, but I just felt it wasn't quite my sound. I tested it with my p-bass, a pf-500, gk 700rb, and an SVT-CL, but I couldn't seem to get the thickness in the low-mids I was looking for. That said, Chris (Kringle77) got a great tone with his gear setup though that design. I believe he has moved onto a different design since using Eminence 3012lfs, in addition to the nv610. The 3012lfs aren't as efficient, but seem to have quite a bit more low-end wallop. There is a video of him playing them with his 70s SVT, and genz benz 9.2, which sounds quite nice too. Still, I would think they would sound best with a lot of watts, which the genz 9.2 definitely provides!

    I also recall a while back that Johnk had some good luck with a sealed 412 V4 cab using Eminence Deltalite II's. They are a lil more expensive, but should be more efficient, and weigh less. I found that with a sealed 212, I was needing a bit more efficiency. Sometimes, you just gotta experiment a lil to find what works best for you though! We all have different tone goals, preferences. It's all about enjoying playing bass at the end of the day, and that comes in many flavors of ice cream!!
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  6. bobcruz

    bobcruz

    Joined:
    Mar 10, 2004
    I can't think of a single reason to use separate chambers for identical speakers. The only thing it would do is stiffen the cab but that can be accomplished with braces for a lot less weight.
  7. Bass_Pounder

    Bass_Pounder

    Joined:
    Jan 19, 2002
    Location:
    Palm Coast, Florida
    I can think of a good reason............

    When one speaker blows, being in separate chambers keeps the remaining speaker(s) performing properly. If two speakers share the same internal airspace, and one goes, the other is now operating outside it's design parameters, and the dead speaker becomes a passive radiator.
  8. BassikLee

    BassikLee

    Joined:
    Feb 13, 2004
    Location:
    Deltona, FL
    Disclosures:
    Owner: Brevard Sound Systems
    Bingo. That, and the tiny added weight for a solid brace in the middle of the baffle.
  9. HaphAsSard

    HaphAsSard

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    Italia
  10. 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)
    Most prosound woofers are optimized for vented boxes because there's a bass extension and/or efficiency penalty when the woofer is optimized for a sealed box.

    The Eminence Beta 12A2 is my first choice in an inexpensive bass-capable stand-alone 12" woofer.

    Imo the Beta 12A2 is a better candidate for a vented box; that would probably have helped in the lower mids. If you still have the cab, it might not be too late to port it.

    I'm working on a midless tweetless vertical 212 (with an unorthodox twist to improve dispersion), and the Beta 12A2 is one of the woofers I'm considering, but it would be a fairly low-tuned vented box instead of a sealed box.
  11. jwindham

    jwindham Supporting Member

    Joined:
    Sep 17, 2006
    Location:
    New Orleans, La
    Thanks Duke,

    I ended up selling the cab, but it would have been interesting to hear a difference with porting. I'm still wondering if perhaps the cab was "out-of-phase" too. I just could not seem to get much definition. It was very "loud" but just didn't have the "thickness" or depth that I was anticipating with my bass, style, and amp choice. It kinda reminded me of a very loud horn- lots of high mids, but lacked the fundamentals for me. I thought the svt-cl with the sealed cab would really shine, but the tone actually fell flat for me,and it felt like I needed a LOT more power to come to "life" if that makes sense. But, Chris with his style/rig always sounded great with them! Arg, I'll never know if it just wasn't my thing, or if the cab just needed tweaking. :meh:
  12. figginalarmguy

    figginalarmguy

    Joined:
    Jul 28, 2013
    Location:
    n.h
    hi
    what i have done with a small pair cab.
    first i build a tilt back for a pair of 10's and ran it with a hartke 140 head.
    "mike it the pa if you need the volume" it was very punchy for me ears so i built and square stand up box and vented it out the sides with and inch and a half all the way around. have a lot of bass but not a lot of punch so i recut the face piece to fit tight to the box and started with ports sizes 2 inch to small the went to 4 inch.
    i figure if i get a box to the point i do not like the tone or sound i can go back to what it was before. ie. cut a 4 inch port in the back can always cut a new back piece if not what i am looking for.
    the only baffled one i have tryed if along the line of the b-15 cabs witch is a front loaded port system.
    have a cab that is running 4 10's and a baffled 15 in it with switches to change between ether set up both at 4 ohms.
    not sure if this helped but time and place to try out ideas really helps
  13. astack

    astack Supporting Member

    Joined:
    Nov 12, 2011
    Location:
    SF Bay Area
    Wonderful form factor.

    Long-winded, but here's a thread that compares a number of 12's that are good for sealed:

    http://www.talkbass.com/forum/f15/12-speakers-sealed-cabs-showdown-emi-vs-fane-926917/

    TL;DR:
    My favorites from listening:
    - Check out the Fane 12-500LF's for growl and fatness
    - Faital 12PR300 16 ohm for very even response and extended highs (up to 5kHz)
    - Deltalite 2512's for a clean and mid-forward response (rising mids and a peak at 2.5kHz)

    If you go for the PF350, I'd say the 2512's are best because of they are significantly more efficient than the other two. Makes the most of the 350W. If the PF800, any of them work, but only the Fane is rated for really serious power. If you're smart and use your ears, the others will be fine with 800W, too.
  14. Jim Carr

    Jim Carr Dr. Jim Gold Supporting Member

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    Denton, TX or Kailua, HI
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    Union card-carrying liberal academic musician
    Two 112 cabinets is probably better, in every way except weight and cost. :eyebrow:

    BTW, what does vertical mean? Can't any non-diagonal cab just be oriented with the speakers one above the other? :confused:
  15. andrklet

    andrklet Guest

    Thanks for all your input!

    The 12a2 is not so easy to find here in Norway, and it's not on Eminence's site. I can't see much difference in the main specs, but your saying it's better in the lower mids? Also in a sealed box? If I go with the 12a, and build the cab to its maximum size, can I then later port it, if I'm not liking the result?
  16. DukeLeJeune

    DukeLeJeune Only immortal for a limited time Gold Supporting Member

    Joined:
    Nov 24, 2008
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    Disclosures:
    Owner & designer, AudioKinesis; Auth. mfg, Big E (Home Audio only)
    The Beta 12A2 is the current version of the Beta 12A, and has been for several years, not sure how many. Here it is on Eminence's website:

    http://www.eminence.com/speakers/speaker-detail/?model=Beta_12A-2

    In a ported cab, you just naturally get more upper bass and lower mid energy than with the same cab sealed. Over the 100-300 Hz region, the Beta 12A2 in a ported cab (1.4 cubic feet tuned to 50 Hz) would average about 1.5 dB louder than the same cab sealed. Not a huge difference, but enough to be audible.

    You can indeed add ports later. I suggest planning in advance where the ports would go, so that you don't "paint yourself into a corner". Here's a thread where someone was planning to build a sealed cab and eventually I suggested ports. There's a fair amount of useful information in our discussion, and he did a great job and took pictures:

    http://www.talkbass.com/forum/f15/general-rule-2x12-sealed-cab-1034379/
  17. Dark Horse

    Dark Horse Supporting Member

    Joined:
    Jul 31, 2008
  18. andrklet

    andrklet Guest

    That is brilliant Duke! Missed one little - while searching the Eminence site. Thanks a lot! Then I would expect the drivers I´ve been looking at are in fact the 12A-2´s. Will check out.

    Now its just a matter of deciding if I should get straight into this, or wait almost an entire month for a shipment of SVT210AV´s to arrive, to test out first. I´m pretty certain they will do the trick for me, but its tempting to build something of my own.
  19. 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)
    That woofer has some really impressive specs and a very smooth looking curve, so I double-checked the claimed efficiency (96 dB) with a modeling program. Based on the other parameters, the efficiency in the bass region is 92.6 dB. And the published curve doesn't show any response rise or peaking that would lead me to believe the average efficiency across its working range really is the 96 dB that's claimed. It may still be a great woofer, but there's some question in my mind about the reliability of its specs. Must admit its claimed 7mm x-max for a $40 woofer is tempting, but I don't know how they came up with that number (unfortunately not all manufacturers measure with the same yardstick). I prefer the response curve of the Beta 12A2, and my confidence is a lot higher in Eminence's specs, but it might be worth $40 + shipping to check out that woofer for other possible applications.
  20. andrklet

    andrklet Guest

    Duke; king of cabs! Are the suggestions you made in the "General Rules..." thread, directly transferable to the Beta 12A2´s?


  21. Dark Horse

    Dark Horse Supporting Member

    Joined:
    Jul 31, 2008
    Awesome ...thanks for the info.

    thanks a ton for all the info and expertise that you (and many others) share around here...ive got tons to learn, and you guys really do help a lot of people !

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