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CX120-8 4" measurement

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  • CX120-8 4" measurement

    Help! frequency response using Omni Mic on a pair of CX120-8 4" drivers show a dip from 1.8k--8k on both drivers. Could this be the Mic or a problem with the drivers ? Measurement taken in a large room, Mic 28" from driver and 44" above the floor. Click image for larger version

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  • #2
    That's a coaxial driver, how did you deal with the woofer and tweeter, crossover?

    Taking a guess, you've just hooked up the woofer and tweeter together, perhaps with a simple cap on the tweeter. Without a proper crossover the tweeter and woofer won't sum properly and can cause all kinds of odd response in that range.
    Electronics engineer, woofer enthusiast, and musician.
    Wogg Music
    Published projects: PPA100 Bass Guitar Amp, ISO El-Cheapo Sub, Indy 8 2.1 powered sub, MicroSat

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    • #3
      OOps, the post was a bit misleading. This was my FRD file for the woofer only. The dip was in the low frequency measurement, woofer only. I used the drivers in two different builds, one ported and a t-line. My crossover using PCD7 was second order elipticle filter on the woofer, and a third order butterworth on the tweeter. The crossover point was 4800 hz. (Not bad)

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      • #4
        Ahh... you're way better off than I anticipated. Also, I don't have any more help That does seem quite different than the manufacture spec graph.
        Electronics engineer, woofer enthusiast, and musician.
        Wogg Music
        Published projects: PPA100 Bass Guitar Amp, ISO El-Cheapo Sub, Indy 8 2.1 powered sub, MicroSat

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        • #5
          It looks similar to me, but the PE measurements are infinite baffle and yours have a baffle step that you have not compensated for. Take out your baffle step and you end up with the same peaks at roughly 1800 and 8000 hz.
          -Bob

          The PEDS 2.1 mini system
          My A7 Project - another small desktop speaker
          The B3 Hybrid Dipole - thread incomplete and outdated

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