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Reload Thread: 4ohm + 8ohm speakers onto crossover

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    4ohm + 8ohm speakers onto crossover

    let's say I use a 4ohm midrange and an 8 ohm tweeter. I use a crossover that's made for an 8 ohm system (or so it says).

    My amp produces about 60w@4ohm stereo.

    What would the actual ohm be?

    or let's say another scenario:

    8 ohm midrange and 8ohm tweeter onto a 2 way crossover. Would that be a final 4ohm load, or an 8ohm?

    Maylar, you there?



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    Re: 4ohm + 8ohm speakers onto crossover

    but one input (from amp) and two output. I want to know what my amp would be seeing..4 ohm, 8 ohm or something else?



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    Re: 4ohm + 8ohm speakers onto crossover

    thanks jmac, you've confused me once more. lol~

    hope to catch you on msn and talk more about it.



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    Re: 4ohm + 8ohm speakers onto crossover

    I know what you mean...and don't know how to explain it either...

    but I think Jmac's saying if the signal sent from the amp is high frequencies, then in "essence" the midrange would not be part of the network (which is impossible as far as I know), or maybe a better phrase is that the load presented to the amp would be primarily comprised of the impedance of the tweeters. Vice versa, if there's low frequencies, the load presented to the amp would be primarily comprised of the impedance the midrange presents.

    ...I think. I don't know exactly how crossovers are wired up but you may have to get into inductive/capicitance reactance in order to calculate the exact impedance. ?? I know you're looking for a general answer, but I'll see what happens when hooking up an 8 ohm nominal impedance in the midrange terminals & 4ohm nominal in tweeter terminals, and see what DC resistance is presented to the amp input terminals of the crossover.



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    Re: 4ohm + 8ohm speakers onto crossover

    ok well here is my attempt at explaining this:

    first the formula for 2 loads in parallel: 1/Rtotal = 1/Rmid + 1/Rtweeter

    When the amp is playing a low frequency, the crossover makes the resistance of the tweeter increase infinitely. So 1/Rtotal = 1/4 + 1/infinity, and Rtotal = 4 ohms.

    When the amp is playing a high frequency, the crossover makes the resistance of the mid increase infinitely. So 1/Rtotal + 1/infinity + 1/8, and Rtotal = 8 ohms

    Now somewhere in the middle there is a combination of the 2 resistances between 4 and 8.

    Like if the crossover made the resistances of each one double, you would get 1/8 + 1/16 = 3/16 = 5.33 ohms



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    Re: 4ohm + 8ohm speakers onto crossover

    i guess i kinda get it...

    thanks people~



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