Sealed 1512 Neo Cab Design

Discussion in 'Amps [BG]' started by kringle77, Feb 7, 2013.


  1. kringle77

    kringle77 Supporting Member

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    Massena NY
    I really love sealed cabs. Nothing else responds like them so, I have no interest in debating anyone on it. I just want to through out an idea that I've been thinking of for a long time. It would be a sealed cab using an eminence 3015lf in a 2-3cubic foot chamber, with a 2512II vertically above it in it's own roughly 1-1.5 cubic ft sealed chamber. The 3015lf would be low passed at 500hz because it has no real character on it's own and the 2512II would be run fullrange. It has alot of upper mid character and good high frequency response on axis. The senativities would match up well. I think that the cab would have good power handling, a fast response, sound like an actual bass cab and really appeal to guys like me who love their berg nv cabs but just are tired of hauling them. I would be using wool batting like bergantino does for dampening and an eminence 600 watts 500hz lp for the 3015lf. Probably would be 17" wide, 30" tall, 15" deep with small tilt back wheels and some sort of handle.
  2. jnewmark

    jnewmark Supporting Member

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    Chris, you are the King of Cabs ! I know it's not the same design, but did'nt Schroeder have a 12/15 cab at one time ? Anyways, sounds good to me !
  3. kringle77

    kringle77 Supporting Member

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    A pair of faital pro 3" mids might be a cool option to stack vertically next to the 2512II. There could be a switch. One position would be mids off, 12 fullrange. Position two would be 2512II low passed at 2khz and the mids taking over. This could really work I think. A really good vintage/modern cab.
  4. eriky4003

    eriky4003

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    I'm no expert, but I thought the 3015LF has to be in a ported cab?
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  6. kringle77

    kringle77 Supporting Member

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    They both model well in sealed cabs and I actually tried the 3015lf in a sealed cab that I used in the past. Worked well and I think that low passing it would really help. The 2512II would being adding all the character and mids while also adding to the 100hz to 500hz region for maximum punch and sealed thickness. I know this design would work well, Im just trying to figure out how some small mid drivers could be added in to enhance the top end of the cab without taking without taking away the growly, bass cab vibe. I think that Im talking myself into this more every second. I didn't realise how good a 12" driver could sound until I got my xsonics 212cf. Now Im on a mission to perfect it for my personal tastes. I've got to assume that the 2512II and 3012ho sound pretty close, the ho of course having alittle more in the 500-800hz region.
  7. bgavin

    bgavin Supporting Member

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    OP, it sounds like you are at the point to start testing real prototypes instead of simulations.

    The RTA does reveal it all... and it is different than armchair quarterbacking.
    Build a few test boxes at the largest expected internal volume, and test them using various volume reducers inside.
    Mine use external vents 4.1" I.D. and various lengths to avoid changing volume inside the box.
    I built interchangeable baffles to allow various size drivers on a given test box.

    Yes, sealed offers the tightest bass response, and much less bass response, but you are OK knowing this.
    The current production 3015LF has a lower EBP (91) than my old originals (102), and requires a larger box.

    New-style 3015LF sealed box size ranges from 3.91 cubic feet (B2) to 9.29 cubic feet (D2).
    Current 2512-II requires 2.27 cubic feet (B2) to 4.37 cubic feet (D2).
    Using these drivers in a too-small sealed box will hump the bass response at resonance and skew your results.
    You can remedy this somewhat by stuffing the box with fiber fill at a rate of 1 pound per cubic foot, for an effective 25% volume increase.
    The RTA will verify the result.

    IMO, overlapping two dissimilar drivers is asking for smearing in the overlap range, especially if they are not time-aligned.
    Punch is heard from the upper frequencies above 100 Hz. The feel comes from those below 100 Hz.
    IMO, cross the 3015LF no higher than 250 Hz.
    It is fully omni-directional here, and less prone to sounding "boxy".

    12" drivers are highly directional and fully beaming by 1339 Hz.
    The off-axis tone loses all its sparkle because the highs are gone.
    The 6" drivers are popular because they don't become fully directional until 2700 Hz +/-.
  8. JGR

    JGR The "G" is for Gustav Supporting Member

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    Look at the phase response in your sim program - that is where you will run into problems if you run both full out on the low end, similar to some of the problems associated with mixing speakers/cabs. I think you would be better off going with a properly executed 15/6/8/10 design, or a dual 2512/whatever, but likely neither will come close to the NV610/412.
  9. rpsands

    rpsands

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    The 3015LF does a fine job in a sealed box. IIRC, around 2.5 cubic feet (might be bigger now, according to Bgavin!)

    It may be worth your time to try running the 3015LF full range but in a slant baffle, as that'd elminate the weird impedance plot you'll get from running the 3015LF low passed with the 12 full range

    Also, I don't think a single 2512 would be a good idea. It'll limit the spl of your overall system to as many watts as a 2512 in a sealed box can take.

    Now, you might be able to alleviate that some by putting the 2512 in a much smaller sub-enclosure (which limits its excursion).

    * You may actually want to look at a Beta 12 LTA. If you've never heard one, they sound awesome, just weak lows.
  10. will33

    will33

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    Neat idea doing something to put some heft under the DL's hot uppermids. If you want to mess with sealed 15 models, the Definimax 4015LF and the FaitalPro 15FH520 may be worth looking into. The Faital has a little higher sensitivity than the D-max and has the response to be passed higher if you choose. Both can take a pretty severe pounding.
  11. kringle77

    kringle77 Supporting Member

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    I've tried the 4015 and prefer the 3015lf sealed. Regaurding the 2-way crossover, I have played with this woofer and several other 10's, 12's, 6's, etc. Whenever there is a full crossover, you never get the same texture, midrange, growl etc, that you get will one driver producing everything on it's own, the best that it can. The best results I got where to run a 10 or 12" fullrange to get that sound most of us like and then to enhance it with a woofer. 250hz to 500hz worked the best depending on which woofer. But in general, lower than 400 or 500hz low pass just took too much balls out of the sound. I don't really understand the phase chart of the speaker program. I don't think that it would hurt the sound much at all but, I could be wrong. Im guessing that what I would get is if you took the frequency chart for the 2512 and bumped up the response by about 3db from 500hz on down. There won't be any comb filtering I dont think. Not very noticable anyway. Sort of just thinking out loud. There have been alot worse designs developed that sound good. Jgr, thanks for re-sending the link for the wool batting. That stuff makes a HUGE difference in the way a sealed cab sounds.
  12. will33

    will33

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    I hadn't realized the 3015LF had been revised, little lower EBP, little more friendly to sealed designs. And yes, the overlapping of bandwidths, though not the technically correct way to do things, can bring a more "raw" sound some people like.
  13. kringle77

    kringle77 Supporting Member

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    Even the best woofer crossed over to a guitar driver cabs I've heard dont' quite do it for me in the midrange. Also, BFM has said that phase cancelation isn't going to be noticed by most people for bass cabs anyway. Comb filtering yes.
  14. rpsands

    rpsands

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    Might want to check out the Celestion BN12-300s, as well. Two of those (4 ohms) in series, parallelled to a 3015LF at an angle maybe.

    Just mad-sciency enough for you ;)

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