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Thread: (semi-) dipole in car?

  1. #1

    (semi-) dipole in car?

    Well, here's the story:

    I want to go 3-ways + sub in the car, but I got a very fucked up dash to work with...

    I was thinking to make some coaxials (mid in enclosure, tweeter mounted to the grill with a hole cut out to pass the dome through).
    I think this might work...
    The rason for this is I got NO space to put a tweeter on the dash (mid already blocking more of the frontward view than I really want). Now since this is the case, I don't really feel anything for big enclosures for the mids either.

    The other option is to vent my mids into the dash... But I would rather avoid cutting up my dash... So I got to wandering and thinking.... And started wondering:
    "What if I made some dipole enclosures for my mids"

    Now I know in home it's been done with very good result, but in a car there's ofourse the biggest restriction ever to get a good dipole: REFLECTION:mad2: (In home you just put your speakers a few inches from the wall to rule out reflections from the backwave).

    Now I was wondering if you could block off reflections by putting some stuffing to the back of your "enclosure", like in: making an enclosure with an open back, put stuffing in it and hold it in place with a metal grill or something so it still a ts as a dipole.

    I've been over this with Isabelle and she thinks it might not work because the waves would still pass through the stuffing and reflect on the windshield anyhow...

    Any thoughts? (I just want some more oppinions before I put this idea on the shelf)
    Thinking outside the box is how knowledge is broadened

    Unfortunately mine doesn't look as sweet as the one in my avatar:cry:
    SAAB 900=> CLARION HX-D2, CLARION APA4300HX(x3), DAYTON IB385-8(x2), Hi-Vi M8a, TANGBAND W4-1337, DAYTON ND20fb
    Future SAAB 99=> McIntosh HU + amps and some drivers

  2. #2
    Tester Extraordinaire ErinH's Avatar
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    hello... I'll just add my comments in here as well as another's who replied to this thread on DIY...

    IMO, the real problem with a dipole setup in the car is boundaries. no matter what, you can't get far enough away from the car's boundaries to mimic a true dipole setup. in a sense, you're always in an enclosure.

    so, the question you have to ask yourself is: how much is close enough?
    We see this a lot with IB talk...
    the thing with the IB subs, though, is that they're pretty close to IB. If you ever model the difference between 5x Vas and 15x Vas, you'll see the results are pretty close.
    What you run in to with dipole setup in a car is simply the boundaries... there's no real way to get away from rear reflections, etc without putting the driver so far away from the nearby boundaries that you've made it a hazard to drive the car. Know what I'm saying?
    This is only my speculation, of course. Trial and error will tell you what works. I just don't see it working out in the car with reasons stated above.


    Quote Originally Posted by cajunner View Post
    well, dipole means sound coming from front and back, so if you tamponade the transmission of sound from the rear, you're just creating an acoustic filter that will absorb some frequencies and allow some to pass, until you've added enough absorbing material to create a closed system.

    in frequency ranges that matter, they smear the sound, as much as diffractions wreak havoc with the near-field of a tweeter. You can't control the rear wave at all, it's going to sum in the corner between the windshield and dash and create a resonant peak, and a null where it passes the speaker's front output. It's just a muddy sound, it's nothing you'd want and doesn't "help" anything. You can approximate this very easily by just putting a speaker without an enclosure up on the dash held by a small baffle.
    I agree with most of this.
    Your ears: The best tools you have... and they're free, too!

  3. #3
    Thx for your opinion Bikini

    I think might try it anyway if it's not too hard to fabricate the "enclosures"... Isabelle is with me to help on the fiberglassing, but I don't have ANY experience with it myself... So I'll certainly be needing her guidance.

    If it turns out for the worst, I can still dremel a few holes in my dash, but on the other hand if it turns out quite well, I still have an untouched dash... AND something UNIQUE that has NEVER been done overhere
    Thinking outside the box is how knowledge is broadened

    Unfortunately mine doesn't look as sweet as the one in my avatar:cry:
    SAAB 900=> CLARION HX-D2, CLARION APA4300HX(x3), DAYTON IB385-8(x2), Hi-Vi M8a, TANGBAND W4-1337, DAYTON ND20fb
    Future SAAB 99=> McIntosh HU + amps and some drivers

  4. #4
    Indecisive Tuner BowDown's Avatar
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    I'm looking forward to this adventure. Being unique and thinking outside the box is what pushes the industry.
    2010 Fusion Sport: SQ Install w/Dash Sub - Build Log of the Month Winner | July 2011


    Nexus 7 | DAC | miniDSP | Aura MR2150 x 3 | NRT18-8 | RS180-4 | neo8-s

  5. #5
    LOL.... I hop you'revnot thinking of retiring yet.... I'm SLOOOOOOOW with things, although I HOPE to get out by this summer.
    Thinking outside the box is how knowledge is broadened

    Unfortunately mine doesn't look as sweet as the one in my avatar:cry:
    SAAB 900=> CLARION HX-D2, CLARION APA4300HX(x3), DAYTON IB385-8(x2), Hi-Vi M8a, TANGBAND W4-1337, DAYTON ND20fb
    Future SAAB 99=> McIntosh HU + amps and some drivers

  6. #6
    Indecisive Tuner BowDown's Avatar
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    Slow progress for a slow car?
    2010 Fusion Sport: SQ Install w/Dash Sub - Build Log of the Month Winner | July 2011


    Nexus 7 | DAC | miniDSP | Aura MR2150 x 3 | NRT18-8 | RS180-4 | neo8-s

  7. #7
    My previous one I didn't dare to push over 118mph (190km/h) (would be a pretty expensive ticket)... This one I didn't take above 80mph (130km/h) yet because I need new tires. SOOOOO NO .... At least not for an 18year old one that exists since 1979 without any mods done to the engine (got from 4 speed to 5-speed though, in '84 I think.

    No, I't more like: slow progress by an überslow girl:unsure: :o
    Thinking outside the box is how knowledge is broadened

    Unfortunately mine doesn't look as sweet as the one in my avatar:cry:
    SAAB 900=> CLARION HX-D2, CLARION APA4300HX(x3), DAYTON IB385-8(x2), Hi-Vi M8a, TANGBAND W4-1337, DAYTON ND20fb
    Future SAAB 99=> McIntosh HU + amps and some drivers

  8. #8
    Founding Member
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    I gotta say.... dipoles in home use have always impressed me... I installed a set of def tech's for a friend and that room sounds really impressive in the rear lol.... semi cheap inwalls up front do the trick tho.
    Daily driver- 06 Tc. w205-h701. Zuki Eleets hybrid 5 channel. Peerless SDS mids, Arc Black series tweeters. Stereo Integrity BM.

    Toy- 95' Lexus Sc300 Build coming soon!

  9. #9
    I'm not planning on changing drivers so I'll have to do with them.

    The frequency-range they're gonna be put in is 250Hz to probably 6.3Khz, so the wavelength is HUGE at the bottom
    Not sure how I'll be going about this.
    Thinking outside the box is how knowledge is broadened

    Unfortunately mine doesn't look as sweet as the one in my avatar:cry:
    SAAB 900=> CLARION HX-D2, CLARION APA4300HX(x3), DAYTON IB385-8(x2), Hi-Vi M8a, TANGBAND W4-1337, DAYTON ND20fb
    Future SAAB 99=> McIntosh HU + amps and some drivers

  10. #10
    The tradeoff here will have to be greater PLD to allow space behind the drivers. I don't see a way around that, short of removing the windshield. If you have a particularly deep dash (Chrysler Concorde comes to mind, for some reason) you may have acceptable results. Stuffing the back will diffuse the backwave slightly, but you'll still have reflections to some degree. Crossing higher would help, b/c waves would be shorter, effectively giving you more space per wavelength.

    Have you considered doing a mock-up and listening to it? This may of necessity be a trial and error affair. ;)
    Experiments should be repeatable: they should fail the same way every time.

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