34" woofer? Is this thing for real?

Discussion in 'Archived Threads 2001-2004' started by ChristianT, Oct 1, 2001.

  1. ChristianT

    ChristianT Extra

    Jul 31, 2001
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    6K each. What kind of enclosure would this thing require?
    I just found these specs at www.audiobahn.com.
    Fs 13.6Hz
    Qts 0.968
    Qes 1 1.2
    Qms 11.65
    Vas 743 Liters
    Vas ?
    Re 1.95 ohms
    Le 1.15mH
    Xmax ?
    Pmax 5000 watts
    EBP ?
    Freq. Resp. 10Hz-400Hz
    Efficiency 88.9 dB
    Depth 14 1/2"
    Hole 34"
    Diameter 36 1/4"
    Displacement ?
    Recommended for a sealed box between 9^3 and 30^3.
    Link to a price:http://www.ultimate-sounds.com/audiobahn/sub32.htm
    [Edited last by ChristianT on October 01, 2001 at 10:26 AM]
    [Edited last by ChristianT on October 01, 2001 at 10:41 AM]
  2. Geoff L

    Geoff L Screenwriter

    Dec 9, 2000
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    I think you more or less answerd
    your own question! At the same time in might be fun to play with some modeling of this (un-proven driver)! The monster has been posted here before,,,, for a go look and see....
    If I remember right, most came to the conclusion that the photo of this driver at Audiobahns site was just a copy of the 12 or 15 of the same line of drivers. The shear mass of the cone would have (me anyway) interested in seeing a real picture and possible cut away of it guts. Thats alot of SD to control and move!
    Certainly would never be buying one, but others have built extrem size drivers (Clarions Thunderdome) and in real world aplications,~~ were at best mediocore performers. This based on reading done in car audio mags and at car audio forums.
    I would think you would see some of these monsters in sound comps, for quailty sound or spl if thier cost matched thier perfomance.
    Recommended for a sealed box between 9^3 and 30^3
  3. GaryM

    GaryM Agent

    Jul 19, 2000
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    If it actually ships, this will be the new record holder (aside from that massive, approximately 90" diameter monster speaker we saw in the original Back to the Future film). The previous "biggest" was the Electro-Voice model 30A woofer produced in the 1970s, which was 30" in diameter. This speaker was intended for musical instrument uses (and was indeed quite popular with rock bands). There was a subwoofer construction article in Popular Electronics magazine, which used a 3'X3' square, 4' long Terra Cotta chimney flue tile as a non-resonant enclosure. This subwoofer weighed hundreds of pounds and had significant output in the infra-sonic range. It was infamous for moving furniture around the room it was in, damaging the structure of buildings, and creating a sudden urge to urinate in many listeners during usage in the infra-sonic region.
    One of these EV-30A speakers was used to replace the lower octave of pipes in the famous pipe organ at Radio City Music Hall. This freed up enough room to create another badly-needed dressing room, and nobody ever complained about any difference in sound.
    [Edited last by GaryM on October 01, 2001 at 07:41 PM]
  4. Rick Chwiendacz

    Jun 27, 2001
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    Well, I ran the numbers and with that Qes, Fs, and Vas, (which are all from their website), I get an efficiency of 84.4dB/W/M.
    For a subwoofer that large, that's pitiful. Even if you assume that it can handle the 5000W RMS that they claim, you're still thermally limited to 121.4dB in a sealed box, at 5000W input power.
    That may seem quite impressive, until you look at the fact that a Blueprint BPD1803 can give you 122.4dB in a sealed box at its rated 1000W power input, and if you need a little more output, I guarantee you the BPD1803 can handle the 2000W needed to get 3dB more output far better than the Audiobahn woofer can handle 10,000W.
    As an interesting sidenote, Sd looks to be about 5200cm^2, and Mms at about 7000g!
    The woofer's biggest downfall is its unbelievably tiny suspension compliance at 0.020mm/N, which is required to keep the Vas to a reasonable level and not require a 300 cubic foot box. This kills the efficiency, and results in the horrible 84.4dB/W/M rating, which makes the entire thing pretty much useless. Other than a prop in a movie, this woofer is 100% worthless in a real-world application, and I pity anyone who actually put out the $6000 to buy it.
    If you were to give me a choice between the BPD1803 and the AWT34x at the *same* price, I'd still choose the BPD driver - it's better in almost every way. Sorry to play the devil's advocate here, but I hope nobody fantasizes about buying one of these. You don't want one - trust me.
    One last note, though. I'm not saying that all large woofers must necessarily be worthless. A 34" woofer done *correctly* has the potential to be incredible. However, the Audiobahn isn't it. If I'm to pay $6000 for a subwoofer driver, I'm going to want a better motor structure than what that thing has for sure, among other things.
    - Rick
  5. Rick Chwiendacz

    Jun 27, 2001
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    One other thing to consider - cone breakup modes in a driver like that are likely to be down real close to the sub's usable bandwidth, and considering that 30" cones are hard to come by, I'm willing to bet that the technology and manufacturing for it aren't very mature.
    If you like high-Q breakup modes at 200-300hz, then this is the subwoofer driver for you. [​IMG]
  6. Philip Hamm

    Philip Hamm Lead Actor

    Jan 23, 1999
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    I want the woofer from the beginning of "Back to the Future".
    rock and roll!
    Philip Hamm
    Pat's the best!™
    AIM: PhilBiker
    click on the little green house to see the evolution of my home theater!

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