I just tested my 6-driver IB wall ... my head hurts

Discussion in 'Home Theater Projects' started by Javier_Huerta, May 10, 2003.

  1. Javier_Huerta

    Javier_Huerta Supporting Actor

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    So I finally decided to start building something, while I can get my Tempest fixed.

    I took some MDF, 1.20 x 1.20 meters in size. Had a carpenter cut the required holes in it, semi-bolted 6 12" Cerwin-Vegas in them (HED-12, 22 Hz Fs, 17 mm Xmax, $60 each!), used one voice coil so as to have a Qts of 0.69, connected my PE300-794 amp to them with a 6-ohm total system resistance, and quickly burned a CD with test tones.

    Did I mention the test tones started at 10 Hz? [​IMG]

    I slowly turned up the volume on the contraption. I expected to hear plenty of distortion in the form of second and third harmonics on the 10 Hz track (I mean, $60 for some C-V drivers? I didn't expect too much).

    I looked at the drivers moving. No sound at all. Cranked the amp's volume up. The drivers started moving so far, I don't think I've ever seen cones moving like it. No sound whatsoever. Turned it up more. At halfway point, the drivers were moving like crazy - I guess they DO have 17 mm. Xmax - and no sound whatsoever is coming out of them.

    My body, though, is physically reacting to the sound. I feel very dizzy and my head hurts. I turn down the volume. Could it be?

    20 Hz come up. The cones move like crazy, and a very faint low tone comes up. 40 Hz come up. The whole contraption starts jumping on the floor!

    Conclusion: 272 watts RMS + 6 drivers on an IB = possible path to sonic nirvana.

    Now, all I need is for my architect to finish up my house so I can mount the thing somewhere.

    I. Can't. Wait.

    [​IMG] [​IMG]
     
  2. Jonathan T

    Jonathan T Second Unit

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    Hey, I have a house, why don't you send it to me so it can be put to use!![​IMG]
     
  3. JoelTW

    JoelTW Stunt Coordinator

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    Man, I wish I could see 6 drivers moving sumulatenously at a 10Hz tone...lol that would be great [​IMG]
     
  4. Scott Simonian

    Scott Simonian Screenwriter

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    That sounds great Javier!

    It is good to see you went with the IB. I bet you are going to love it.

    Give us some more impressions. I would sure like to hear them.

    [​IMG] [​IMG]
     
  5. Javier_Huerta

    Javier_Huerta Supporting Actor

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    Joel: I'm thinking about taking some video of the drivers and uploading it. I hadn't seen drivers moving at 10 Hz, either. They look amazing - the cone movement must be seen to be believed.

    Jonathan: NO way. Remember, I live in Mexico, so S/H costs would be more than what I originally paid for the thing. [​IMG] Still, replicating the entire system would set you back $360 for the drivers and $120 for the amp. I don't think that's expensive (at all). Sure beats other common alternatives (such as the Parts Express IB drivers).

    Scott: I'll try to mount the IB baffle somewhere around here (highly doubtful - I see nowhere to install it) and post more info. Or pics... yeah, I'll try to do so later today.
     
  6. Dave Milne

    Dave Milne Supporting Actor

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  7. Jonathan T

    Jonathan T Second Unit

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    Javier: I was just kidding.[​IMG] You enjoy your creation. I got 2 AV-12s comming as soon and the wallet allows it. So I can bring down my house too!
     
  8. Javier_Huerta

    Javier_Huerta Supporting Actor

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    Dave,

    The room the IB will be mounted in is all made up of concrete, bricks and mortar.

    The design is not based on the fact that I'll be mounting an IB there, but rather because constructions around here, in fact, have to be earthquake-resistant. [​IMG]

    I'm sure a nice side effect will be zero rattles and noises, though.
     
  9. Scott Simonian

    Scott Simonian Screenwriter

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    Just wait for all that room gain.

    You are in for it. Hehehe.
     
  10. Javier_Huerta

    Javier_Huerta Supporting Actor

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  11. Javier_Huerta

    Javier_Huerta Supporting Actor

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    Picture of the driver:

    [​IMG]

    I bought 4 blue drivers and two red ones. Fit and finish are *perfect*: the cones seem to have a metallic finish and a propylene cone.

    [​IMG]

    Here are the six drivers, wired to present a 6 ohm load to the amp. I really like their looks - photos don't really do them justice. In the upper right corner, you can see my SACD (DVP-NS900V) box. And yes, you read that right: somehow, Sony can legally sell DVD players modded to play all regions. Beats me, but it's a nice thing to have.

    [​IMG]

    This pic puts things in their proper perspective. Check out the size of the Tempest... it's HUGE! The little 12's seem to tremble in comparison.

    In reality, though, since my Tempest has some kind of defect I can't use it. For now. I'll get it fixed sooner or later.


    [​IMG]

    Another pic that shows the huge difference in size between the Tempest and the C-V. As you can see, I already had my Tempest wired in parallel, ready for use [​IMG] The C-V's have one VC disconnected.

    I think I spent 3 hours terminating all cables for this test.

    [​IMG]

    What can I say. I like the C-V driver's looks. It's a really cool driver for the price.
     
  12. Scott Simonian

    Scott Simonian Screenwriter

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    Hey, those drivers do look like the av12s. Nice colors, I like red myself. What is wrong with your Tempest? If you dont want it, I would be happy to bring in a 2nd.

    [​IMG] [​IMG]
     
  13. Mark Shannon

    Mark Shannon Screenwriter

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    Three words... OH MY GOD!
     
  14. Javier_Huerta

    Javier_Huerta Supporting Actor

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    Heh. Thanks [​IMG]

    The Tempest has some problems. It has a loud noise when driven at medium levels. It sounds like lead slap.

    The fact that it was defective drove me nuts enough as to try an IB wall.

    I wonder what would happen if I added 3 more drivers to the mix... I could get two reds and a blue one, and have some kind of pattern in it! Ah, the sweet joys of excess. [​IMG]
     
  15. MichaelAngelo

    MichaelAngelo Stunt Coordinator

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    Javier,
    It may be a bit late, but I saw on Ebay an ad for refubished Sony car subs, the red XPlods, ten 12" drivers for ~$400.00 US.

    w00t for multiple bass drivers !
     
  16. Geoff L

    Geoff L Screenwriter

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    Javier

    Never hurts to have toooo much, a few more, why not!

    Is that some type double roll on the surround?

    Those cones are very sharp, but would prefer just the typical CV logo in "Copper", or whatever the cone color is on the Dust Cap.
    This, opposed to the red or blue background....

    But just me preferance and certainly dose not matter what I think.[​IMG]

    Still they look very nice and the price is very right!

    Sounds like a man with a plan,,, and with room gain, OH YES! [​IMG]

    Regards
    Geoff
     
  17. Javier_Huerta

    Javier_Huerta Supporting Actor

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    Michaelangelo, I'd definitely NOT get the Xplod subs from Sony.

    First of all, check out the reviews. In every car audio forum I could find, Sony Xplods are considered some of the worst subs to get. Reason being, people say they "destroy" themselves easily.

    Check their specs. I think their Xmax is something like 4mm *or less*. That's not exactly the path towards deep low extension. I'd guess those subs would work well on a system that was high-pass filtered to 35 Hz or higher.

    Those same people told me C-V drivers were reliable and that their T/S and Xmax parameters were usually on-spot.

    Geoff: they do have a "double roll" surround. According to C-V, this helps in positioning the voice coil during high excursion, so as to avoid the VC slapping the magnet. When the C-Vs are playing softly, you can see the inner fold moving - only when they are really taking advantage of that massive Xmax do you see both surrounds moving.

    As for the center cap colour... they do look nice, actually. But I can see your point - an all black dust cap with silver accents would look very good, too.

    As a matter of fact, I think I won't build a manifold for two reasons:

    1) As someone stated in the Cult of the IB forum, a 6+ driver manifold creates some problems with time alignment and phase, depending on where you are sitting on the room.

    2) I think the speakers would look *right* on an IB wall in a dedicated HT room.

    I'll try to post some pics of the room they'll be mounted on as soon as I have time (the room was in the lot before the house was built, so it needs some serious repair work).
     
  18. Javier_Huerta

    Javier_Huerta Supporting Actor

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    UPDATE:

    I went out yesterday and bought 3 more drivers.

    I rationalized the fact when I thought to myself... "Well, I'll get some extra headroom, and the drivers will only be fed 30 watts each, and it'll look better..."

    Actually, the only rationale I needed was I'd be getting a lot more SPL's with (hopefully) less distortion. Plus, by using 3 3-driver series arrays in parallel (12 ohms from each 3-driver series array, 3 times parallel = 12/3 ohms total system impedance) I'd end up with a system that maximizes the output of the 300-794 without straining it.

    I'll try to take some more pics of the whole system built when I have the time.
     

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