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Eminence MAGNUM

Discussion in 'Amps and Cabs [BG]' started by tufnuts, Jul 28, 2002.

  1. I've been wanting to build a new cab, being as way pleased with my 2 2x10's and 1x15 that I built using eminence speakers. I'm going to start playing with alternate construction techniques that I've learned since I've built my cabs.

    And now the MAGNUM series of cabs is available. And the 18" seems like it could kick some serious a$$. But the 15's seem like possible players also. The only reason I'm looking at the 15/18's is that I'm very very happy w/ my delta 10'ed cabs. My kappa pro 15LF 1x15 is good, but more is more...and more. Mmmm.

    WEIGHT! Get the @#$#@ weight down! I had to haul all of my cabs last week to a jam session, and they are very portable...but still way to heavy. Lightweight, stiff materials are the key. I'll figure something out. It'll be a composite material that will be formed w/ 5 of the sides at once, and then a seperate front piece bolted on/sealed...etc.

    It's all good.
  2. Beefbass

    Beefbass Guest

    Feb 4, 2001
    Sounds like a winner-let us know how it turns out.
  3. jasonbraatz


    Oct 18, 2000
    Oakland, CA
    i'd love to have a set of carbon fibre cabs.

    imagine a 4x10 with neodymium drivers and a carbon fibre shell. it'd weigh about 30 lbs.
  4. geshel


    Oct 2, 2001
    I just noticed Ampeg's Portabass series, they have Nd-magnet woofers in them. The 2x10 is 32 pounds! Wonder how they sound. Their website is pretty shy of specs (they have "n/a" next to "frequency response" :rolleyes: ).
  5. The portabass 2x10 sounds wonderful. And that's about the best way to put it. After playing one of those, then gettin to tote it a bit....really got me thinking. Something can sound good, be compact, be light. Plus some of the mackie stuff is a composite cab.

    I don't know about CF though. But I can tell you it'll have a core. Just figuring what to use so that I can use it in the garage is the thing. I've seen some home vaccum bagging techniques that use a wet-dry vac...that sounds like fun :)
  6. The Magnums are interesting, but all require large cabinets.

    15LF in 8.7 cubic feet is good to 29 Hz
    18HO in 6.9 cubic feet is good to 42 Hz
    18LF in 6.7 cubic feet is good to 41 Hz.

    The Magnum 15HO isn't acceptable as an electric bass speaker. It is -3dB at 54 Hz. Too high.
  7. That's about what I was thinking bgavin, so that's why I was freaking out about the weight that would be needed for a cab that size. But I'm also wondering about acoustic filler used to increase the apparent size of the cab. Matter of fact, I've always wondered why this isn't used to help reduce cab size and provide some extra dampening.

    This all actually came from an accident I had in the model area here at work. I was using some poly foam underneath a part that I was doing a wet layup on w/ polyester resin. The foam that was underneath absorbed the resin, and formed a VERY stiff (stiffness is key) and lightweight composite. So my idea would be to use some of this foam as a very light weight reinforcement to stiffen up a 0.12" layer of normal chopped mat fiberglass. Would be way cheaper than a kevlar, along w/ having acoustical damping properties still. And wicked stiff (Mr. Deeds reference)

    So, what it comes down to, is that I'm hopin to be able to build a couple little shells that I can hack apart and test the effectiveness of this resin-impregnated foam along w/ a lining of an acoustical dampening material to vastly decrease the needed volume for the cab. The exterior layer of glass is just there to protect the foam.

    Anywho. Just thinking out loud...and on paper...and in the lab...and in the garage...lol.

    I don't have the time and cash to pull it off yet though....if anyone wants to fund my research.. ;)
  8. geshel


    Oct 2, 2001
    The only cases I've seen where filler was used were for sealed boxes. For a ported box, it can get in the way of the port's effectiveness. Anyway, the most I've seen claimed for an "effective increase" in box volume (and the jury's out on that one, I think) is around %5. Nothing too amazing.
  9. Acoustic filler is typically used in sealed boxes, and can yield up to 30% apparent increase in volume for small boxes, and a lesser percentage for larger boxes. Tom Nousaine has published his test method and results.

    Link to Filler Test and Results

    The principle is the same when applied to a vented box, but is strictly trial-and-error because the volume surrounding the internal vent opening must be kept clear of stuffing. This requirement will preclude its use in commercial cabs that are produced by assembly line.

    I've thought about it long and hard, but my cabs are already fairly large at 5.4 net cubic feet internal volume. However, my next pair of subs are going into sealed boxes, and I will be using 1 pound of filler per cubic foot in this case.

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