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-   -   Subwoofers ohms (https://www.askmehelpdesk.com/showthread.php?t=86360)

  • Apr 25, 2007, 10:17 PM
    NorCal68
    Give me a few minutes to take a look - and I've got one other email to finish. Back in a bit...
  • Apr 25, 2007, 10:18 PM
    millertime
    OK thank you so much for your time
  • Apr 25, 2007, 10:30 PM
    NorCal68
    I'll be back in a couple minutes... lots going on. Lol
    Check this out, OK?
    http:// www. Crutchfield. Com/ISEO-rgbtcspd/learningcenter/car/subwoofers_faq.html
  • Apr 25, 2007, 10:34 PM
    millertime
    OK thanks just get back to me on the subs on which one u think is better thanks
  • Apr 25, 2007, 10:39 PM
    NorCal68
    Dual Voice Coil Subwoofers

    Read the above article as well...
  • Apr 25, 2007, 10:40 PM
    millertime
    I am reading them at the moment
  • Apr 25, 2007, 10:48 PM
    NorCal68
    Ok, this is getting pretty technical (not a problem - I taught advanced audio engineering) so let me try to simplify this: You amp choice and speaker choice don't match as well as they should. Basically, the speakers are Dual Voice Coil (DVC) and the amp you've chosen will 'see' these spkrs as 8 ohms each... which is not getting you much power. Either get Single Voice Coil spkrs at Four Ohms each.. OR.. find a single channel/Mono amp that is rated for Two Ohms output. You're on the right track, but everything isn't quite matching up.
  • Apr 25, 2007, 10:53 PM
    millertime
    So what if I were to get a dual voice coil 2 ohms speakers would the amp see it as 4 ohms instead?
  • Apr 25, 2007, 11:05 PM
    NorCal68
    So what if I were to get a dual voice coil 2 ohms speakers would the amp see it as 4 ohms instead?

    Yes!

    Or, check out this speaker...

    BOSS AUDIO BL128 Blade Series Metallic Injection Cone Subwoofer (12" Single voice coil) - ( AUTOTOYS.COM )
  • Apr 25, 2007, 11:07 PM
    NorCal68
    And now I've got to sign-off for tonight - early day tomorrow. I'll check for messages in the morning and follow-up with whatever info I can provide.
    Thanks for a great question tonight!
    David
  • Apr 25, 2007, 11:08 PM
    millertime
    You I looked at that speaker the max watts are 700 though
  • Apr 25, 2007, 11:09 PM
    millertime
    What about these ones
    LANZAR OPTI1222D DUAL MAGNET 2 OHM WOOFER - ( AUTOTOYS.COM )
    I believe they are dual 2 ohms voice coils
  • Apr 26, 2007, 10:44 AM
    BTA
    Quote:

    Originally Posted by NorCal68
    so what if i were to get a dual voice coil 2 ohms speakers would the amp see it as 4 ohms instead?

    Yes!

    Half true. He could wire the coils in series for 4 ohms or parallel for 1 ohm.

    If you bought two, dual-coil (2ohms/coil) speakers then you could wire the entire system into several different configurations to match your amplifier(s). It is essentially like having 4x2ohm resistors to do what you like with.

    If you wired all four coils in series you'd get 8ohms, for example. If you wired each speaker's two coils in series with each other, then wired the two speakers in parallel, you'd have 2 ohms overall, etc.

    The trick then is to match impedences with your amp's optimum output. If you want "x" watts, choose an amp that will put out "x" watts (rms) at "y" ohms. Then wire your speakers to get "y" ohms.

    Some amps will offer you multiple channels... this lets you simplify the wiring and run each sub on different channels if you so choose. Alternatively, some amps will let you "bridge" two channels together to half the impedance.

    Make sure you choose a conductor based on the overall amerage that will be running through your system:

    If you have a total impedance of 8ohms, for instance, and your power is 1000W (rms) then your amperage is going to be I=sqrt(P/R)=sqrt(1000/8)=11.2A. Your peak current will be 11.2*sqrt(2)=16A. A #12 AWG wire should be used.

    If, however, your total impedance is 1ohm, and your power is 1000W (rms) then your amperage is going to be I=sqrt(1000/1)=31.6A. Your peak current will be 31.6A*sqrt(2)=45A. In this case a #8 AWG wire should be used. (2 sizes thicker than before!)
  • Apr 26, 2007, 11:25 AM
    NorCal68
    Okay….. lets try to take this down to the lowest common denominator:
    1. Millertime has a hot Camaro.
    2. He wants a killer sound system.
    3. He would like to achieve maximum 'thump' for the $$ invested.
    4. Item #3 above (and my answers) are in direct proportion to the initial posting, i.e. Subwoofers.
    5. My responses are directed toward actually reaching the intended goal (as a practical application) and less in the context of a E.E. lesson.…

    So, that's about it! And my information to Millertime came from His choice of components.
    I do appreciate your input - but I believe bridging & sqrt formulae are not what he had in mind.
    And as Dennis Miller always says "these are just my opinions .. I could be wrong" ……
  • Apr 26, 2007, 06:51 PM
    millertime
    So would these subs work LANZAR OPTI1222D DUAL MAGNET 2 OHM WOOFER - ( AUTOTOYS.COM ) I just want to double check and make sure and should I use 4 gauge wire?
  • Apr 29, 2007, 02:25 PM
    NorCal68
    To any and all who were following this thread or may have wondered why it slammed to a halt in mid-stream... by mutual consent, it moved to a different location. Millertime has his system figured out and all ended quite well.
  • May 13, 2007, 08:28 AM
    Stratmando
    2 8 Ohm speakers wred in parrallel(plus to plus and minus to minus) does bring resistance(Impedance) down to 4 Ohms.
    If you had 2 2 Ohm speakers and wire in series(Plus of one speaker to negative of other speaker)and with the plus and minus remaining, go to amp output.

    You can do a series/parallel with 4 8 ohm speakers to end up with 8 ohms. Output to each individual speaker will be reduced, and Amp will not be loaded down.
    Wiring these same 4 speakers in parallel would reduce to 2 ohms(Bad for 8 ohm Amp)

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