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Question about Speedster crossover components

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  • Question about Speedster crossover components

    Hello everyone,

    I am interested in building a pair of Paul Carmody's Speedsters for myself. However, since I am not living in the USA I cannot buy a kit from the usually recommended sites. A local shop has almost everything I need but does not offer some of the inductors for the crossover.

    The BOM lists L1 as .25mH 20AWG and L3 as .35mH 18-19AWG.

    The closest my local shop offers is 0.27mH 21AWG and 0.33mH 18AWG. I can only find the correct inductors at a much higher price and I would also have to pay shipping for another shop. I would really like to avoid that.

    I don't have much experience in building speakers and crossovers. So sadly I can not evaluate how much changing the inductors will change the sound of the speakers. Will there be a noticable difference in sound if I build the crossover using the slightly different inductors that I mentioned above? Or are the differences small enough to be not (or only barely) noticable?

    I hope you can help me and I am really looking forward to your answers.

  • #2
    Do you have anything to test inductance with? You could always buy bigger values and unwind.

    Where are you located?

    I don't think it will make a huge difference but might be enough to alter the sound slightly from the original design depending on how tight the tolerance to those numbers are. If they swung wide the wrong direction, you might be a decent bit off.


    • #3
      In situations where I can't get the exact value, I'll typically get the next larger inductor and just unwind to the value I need - but I have an LCR meter to measure. Those values are more or less within the +-5% tolerance commonly applied to inductors, so you'll likely be OK, unless the indicutors you buy are also at the extreme limit of their tolerances too. The wire gauges should be ok in my opinion.


      • #4
        Thank you for your responses. Sadly I don't have an LCR meter. Therefore I am uncomfortable with buying bigger and unwinding because I can not measure the result.

        I am located in Germany. It's hard to believe but I could not find a local (online) shop that sells the right inductors. Although I have found another european shop that sells 0.25mH 20AWG inductors for a reasonable price. They also have 0.35mH inductors but they come either with 20AWG or 15AWG.

        I just had the idea to buy the 0.35mH inductors with 15AWG and solder a 0.1Ω resistor in series to compensate the inductor's lower resistance (from the higher wire diameter). Would that work or am I oversimplifying and there's more to the inductor than inductivity and resistance?


        • #5
          If you use the 15ga, you'll gain a TINY bit of efficiency on the woofer, but I don't think it's something I could hear. I personally wouldn't worry about it.


          • #6
            Use the ones you've found.
            You'll never know the difference.


            • #7
              Do you mean I'll never know the difference because I don't have a comparison pair of speakers or because it basically doesn't make a difference? :P

              Thanks a lot for all your input. Considering everything that was posted here I will just go with the easily available inductors.


              • #8
                I also want to build Speedster, but the local distributor Fountek NeoCD1.0 (81 $) is too expensive