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perisoft
Joined: 29 Aug 2007
Posts: 2920
Location: Ithaca, NY
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| Posted: Wed Sep 26, 2007 9:53 pm Post subject: Big, honking subwoofer drivers - where can I get 'em cheap? |
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So I'm working on planning my HT, and starting to think about the audio bits. I've wanted to have a ludicrous amount of bass since I started this project - I just like it, what can I say - so, being on a limited budget, have been trying to figure out a way to do it on the cheap.
I was talking with my dad about this (he's the main engineer with my company, tons of experience with electronics as well as mechanical design), asking him about rolling my own amp, and he says, "Oh, jeez, you could, but we've got this big stack of power amplifiers we got somewhere, it'd be easier to just use those."
Turns out we have these 2 kilowatt power amps that came out of some MRI. We've got 18 of them. Yeah, thirty-six kilowatts worth. So *power* I have.
The biggest issues are matching them to the speakers, and making sure that a little pop doesn't set them on fire (which it could, quite easily).
Anyway, being as subs suck up the most power I thought I'd see if anybody knew of a place to get some really, REALLY gargantuan drivers on the cheap. I don't really care if they're *good*; movies generally just go 'ooooom' anyway. So basically, how do I find drivers that can handle 4 or 6 kilowatts of input?  (Maybe just two. Wimpy, I know...)
And yeah, I like the idea of it being totally, ludicrously over the top. And my neighbors aren't anywhere near me - so as far as I'm concerned, it's time to figure out how to make a physically dangerous subwoofer setup. I want my buddies to have to pick themselves up off the floor after a grenade goes off on-screen! Any suggestions? 
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CRT_Ben
Joined: 28 Aug 2006
Posts: 1684
Location: Northern Virginia
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| Posted: Wed Sep 26, 2007 10:11 pm Post subject: |
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Heh...
Madison Sound ExecutionerX 21" drivers - my brother has two of 'em - they come up on the 'bay from time to time, and you can usually get a PAIR for about ~$300 delivered. Let's just say that they rock the house.
Specs, and pictures:
-200oz magnet structure
-4" 8ohm voice coil
-cast frame
-1000W RMS/2000W Peak
-18mm Xmax
Here's the Craigslist ad that I pulled the pics from, it's one for $100:
http://raleigh.craigslist.org/ele/432188966.html
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perisoft
Joined: 29 Aug 2007
Posts: 2920
Location: Ithaca, NY
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| Posted: Wed Sep 26, 2007 10:26 pm Post subject: |
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That's what I'm talking about. Now I just have to find out where I can get eight of them... think that'll fill out a 12x15 foot room? 
(Forget using a bass shaker attached to the seats... I'll just mount a floating floor on the speakers! Muahahaha....)
Edit: I just checked the CL ad you linked... I just busted out laughing when I read, "...I ran this sub with a small Parts Express Plate Amplifier and it was shaking my sheet rock loose."
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rabies_70
Joined: 15 Feb 2007
Posts: 1189
Location: Carlsbad, CA
TV/Projector: Sony G70Q
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| Posted: Thu Sep 27, 2007 12:00 am Post subject: |
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Check out the cult of the infinitely baffled. Not sure if you know about IB or not, but as soon as I saw what it could do I had to build one. Now that I hear what it can do I hope I never have to be without one again. I use 4 Dayton AE 15" IB speakers in an "outtie" box and I can't even imagine what goodness would happen in my theater with more. I have never heard a deeper more full response all distortion free from any other subwoofer setup. Oh yeah, it FEELS awesome too. When something blows up on screen, you feel like you're blowing up and when something rumbles by you sit there and rumble too. As an added bonus during normal listening it does't overpower but instead just blends right in and plays nice with all the other speakers in the room....
http://ibsubwoofers.proboards51.com/index.cgi
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I am an iconoclast
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Thu Sep 27, 2007 12:06 am Post subject: |
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Depending on how cheap you want to go, troll Craigslist for old speaker cabinets. Anything by EV or JBL with decent power handling will kick ass. You can usually get cabs for $50-100 each, esp. if the seller has no idea what's in them.
Someone here or on avs got a pair of homemade speakers for $10 or $50 or whatever at a thrift store not long ago. Turns out they contained Tannoys which easily were worth $1K a pair..
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perisoft
Joined: 29 Aug 2007
Posts: 2920
Location: Ithaca, NY
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| Posted: Thu Sep 27, 2007 1:13 am Post subject: |
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Heh, funny you should mention that, Curt... I mentioned it on a thread or two here, but I recently traded a pair of OK-ish Altec Lansing floor speakers (two-way, 12" main drivers and a mid/tweeter - OK power but terrible mids) for a pair of mint Cerwin Vega VS-120s. I did an A/B comparison for the guy to see if he still wanted to trade (he wanted something smaller...) and I thought the Altecs were broken after listening to the Cerwins. He took 'em anyway. Loves 'em, apparently. Go figure.
Anyway, these Vegas are insane... each one of them has more sub bass than the 12" sub I put together last winter, and they're only being driven to about 1/5th of their rated capacity (250 watts per at 4ohms!@$).
But those are going to be the fronts... I can route some LFE through them with the software, but I want seismologists to run to their equipment when the THX sound plays, damnit!
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garyfritz
Joined: 08 Apr 2006
Posts: 12088
Location: Fort Collins, CO
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| Posted: Thu Sep 27, 2007 3:00 am Post subject: |
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| rabies_70 wrote: | | Check out the cult of the infinitely baffled. |
What he said. Check out infinite baffles and you'll never turn back. Google for "cult of the infinitely baffled" and you'll find a bunch of sites with TONS of info, especially https://home.comcast.net/~infinitelybaffled/. If I had the right setup, and if my wife wasn't such a bass-o-phobe, I'd definitely build one.
About 4-6 months ago there was an absolutely insane woman over on the A site that was building an over-the-top theater (sound-wise anyway) in a fairly small room. I can't find it now, maybe somebody knows where it is, but it included a ludicrously over-spec'd infinite baffle in the floor with some number of mondo-expensive kilowatt amps pushing it. We were all speculating whether her house was going to literally crumble when she cranked up the sound... we figured at a minimum the walls were going to flap in the breeze!!
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rabies_70
Joined: 15 Feb 2007
Posts: 1189
Location: Carlsbad, CA
TV/Projector: Sony G70Q
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| Posted: Thu Sep 27, 2007 3:25 am Post subject: |
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That was Dirty Harriet and her setup was CRAZY (in the nicest way). If you got to the cults website theres a couple pics somewhere.
http://ibsubwoofers.proboards51.com/index.cgi
I asked about her last month. They said she flipped out when every one was telling her that the foundation might shift and windows would probably break. I dont know why she didn't take their advice, I followed the advice given by Thomas and the others and zoinks 
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I am an iconoclast
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jask
Joined: 17 Mar 2006
Posts: 10187
Location: kamloops BC
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| Posted: Tue Oct 02, 2007 12:38 am Post subject: |
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| Curt Palme wrote: |
Someone here or on avs got a pair of homemade speakers for $10 or $50 or whatever at a thrift store not long ago. Turns out they contained Tannoys which easily were worth $1K a pair.. |
What a lucky bastard he was.... oh wait ...that was ME!!!! if it makes you feel better they are only good for about 30 watts.
I am with curt on the old EV or JBLs>> big power cheap.
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Mark_A_W
Joined: 15 Mar 2006
Posts: 3068
Location: Sunny Melbourne Australia
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| Posted: Tue Oct 02, 2007 1:01 am Post subject: |
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| rabies_70 wrote: | Check out the cult of the infinitely baffled. Not sure if you know about IB or not, but as soon as I saw what it could do I had to build one. Now that I hear what it can do I hope I never have to be without one again. I use 4 Dayton AE 15" IB speakers in an "outtie" box and I can't even imagine what goodness would happen in my theater with more. I have never heard a deeper more full response all distortion free from any other subwoofer setup. Oh yeah, it FEELS awesome too. When something blows up on screen, you feel like you're blowing up and when something rumbles by you sit there and rumble too. As an added bonus during normal listening it does't overpower but instead just blends right in and plays nice with all the other speakers in the room....
http://ibsubwoofers.proboards51.com/index.cgi |
Me too
Mine is here
http://www.duffroomcorrection.com/wiki/User:Mark_Wilcock
And here
http://home.comcast.net/~infinitelybaffled/page10IB-MarkWIBdesign.html
IB is so good and so easy it's ridiculous.
I've found 4 Tempests to be massive overkill..2 would be fine.
Mark
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Tom.W
Joined: 09 Mar 2006
Posts: 6635
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| Posted: Tue Oct 02, 2007 1:52 am Post subject: |
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Love Focal drivers. I have a set of Audiom 4 and 7 drivers. They sounded great with an infinate baffle. Now unused but plan on trying a new design soon.
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Mark_A_W
Joined: 15 Mar 2006
Posts: 3068
Location: Sunny Melbourne Australia
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| Posted: Tue Oct 02, 2007 2:05 am Post subject: |
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Mmmm...Focal
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Moose
Joined: 09 Mar 2006
Posts: 788
Location: Minnesota
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| Posted: Tue Oct 02, 2007 3:27 am Post subject: |
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| Quote: | | The biggest issues are matching them to the speakers |
Is this your only problem? Will they run on household current? I'd think amps that are designed to function with an MRI might require a non-standard electrical supply.
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Tom.W
Joined: 09 Mar 2006
Posts: 6635
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jask
Joined: 17 Mar 2006
Posts: 10187
Location: kamloops BC
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perisoft
Joined: 29 Aug 2007
Posts: 2920
Location: Ithaca, NY
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| Posted: Wed Oct 03, 2007 12:27 pm Post subject: |
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| Moose wrote: | | Quote: | | The biggest issues are matching them to the speakers |
Is this your only problem? Will they run on household current? I'd think amps that are designed to function with an MRI might require a non-standard electrical supply. |
My dad didn't mention it so I'm guessing they'll run on 110. Even if not, the other benefit of what we do is that we also have lots of huge transformers (they're more than meet the eye...) so I can convert stuff as I need to between 110, 220, etc.
The only reason any of it is practical at all is because I've got a free electrical engineer with 40+ years of experience at my disposal, a shop full of kit, and extra space and power for my setup. It's a perfect storm of opportunity leading to an extremely bassifying experience.
Thanks for the other advice, guys... I'll definitely check out the infinite baffle thing. Biggest problem is I may not have the physical layout to handle it in the room; the back wall is mostly cement chimney, the right side wall is in the ground, the left is toward the bedroom, and the front (where the screen will be) is full of windows/a door and going outside. (I'm building a kind of false wall that will drop in when I run the HT. And when it's cold. )
I wonder what they use for sound reinforcement at live events... I would imagine they suck down a lot of power, and I can't even comprehend how much power a couple of bass drivers that normally attack madison square garden would emit into my 12x15 foot room... No idea if they have some funky huge drivers or if they just use an ungodly amount of 'normal' ones.
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garyfritz
Joined: 08 Apr 2006
Posts: 12088
Location: Fort Collins, CO
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| Posted: Wed Oct 03, 2007 12:31 pm Post subject: |
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For MSG, I think they use an ungodly amount of funky huge drivers.
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perisoft
Joined: 29 Aug 2007
Posts: 2920
Location: Ithaca, NY
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| Posted: Wed Oct 03, 2007 12:49 pm Post subject: |
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| garyfritz wrote: | | For MSG, I think they use an ungodly amount of funky huge drivers. |
Hahaha... we have a lot of high performance servo motors and stuff, too, and it occurred to me to build a platform on which to put the seating, and use five or six servo drivers to make the entire floor into one, enormous, 15kwatt subwoofer driver. But they're actually fairly expensive and we don't built enough kit so six pairs of motors and amps going missing wouldn't get noticed. 
The servo motors and amps we use actually have good response up to about 35, 40hz, so they'd do nicely as a sub-sub-woofer. Anybody want to spend $2000 on a 50-inch, 2kw mother of all sub-subwoofers? I could probably do the hardware for that; it'd be worth the engineering and software time just for the experience!
Only thing with that is I'm not sure how much signal is actually in most movie soundtracks down that low, or if you'd have to synthesize it out of the 'normal' LFE track by 'copying' everything an octave or two down. Though that might work now that I think about it... OK, David. Stop now. Stop *NOW*.
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AnalogRocks
Forum Moderator
Joined: 08 Mar 2006
Posts: 26706
Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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jask
Joined: 17 Mar 2006
Posts: 10187
Location: kamloops BC
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| Posted: Thu Oct 04, 2007 6:17 am Post subject: |
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369 POUNDS!!? 6000WATTS in a car, this might work as a antitheft device as well.
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