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DATS question

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  • DATS question

    Just purchased the DATS system. Checked resistance of the test leads and calibrated using the supplied resistor. Everything went fine, tested my first speaker a W6-2144 Tangband band. The stated specifications stated an Fs of 45 Hz. When I tested the speaker the program came back with an Fs of 56 Hz. Is this type of discrepancy normal. Everything else was relatively close.

  • #2
    I've never messed with DATS or Tangband, but I have read that TB's Fs ratings are sometimes a bit "optimistic".

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    • #3
      How low a driver can go isn't determined by Fs, it's determined by Fs and Qts (together).
      I'd bet that your Qts ALSO came in high (about 0.10 high?).
      You didn't say that you broke them in before measuring. Break in will lower Fs and Qts, and raise Vas.

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      • #4
        Ok, that was my second question. Should the speakers e broke In before testing

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        • #5
          Originally posted by Chris Roemer View Post
          How low a driver can go isn't determined by Fs, it's determined by Fs and Qts (together).
          I'd bet that your Qts ALSO came in high (about 0.10 high?).
          You didn't say that you broke them in before measuring. Break in will lower Fs and Qts, and raise Vas.
          This is where I'm at so far, I haven't done Vas yet:


          Tangband listed tested
          DCR Impedance 6.8 ohm 6.419 ohm
          Free Air Resonance 45 Hz 58.54 Hz
          Levc .01mH .08254 mH
          Qts .45 .4496
          Qms 1.73 1.571
          Qes .62 .6299

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          • #6
            This is where I'm at so far, I haven't done Vas yet:


            Tangband listed tested
            DCR Impedance 6.8 ohm 6.419 ohm
            Free Air Resonance 45 Hz 58.54 Hz
            Levc .01mH .08254 mH
            Qts .45 .4496
            Qms 1.73 1.571
            Qes .62 .6299

            Comment


            • #7
              That driver LOOKs really cool, but probably best suited as a midrange (haven't looked at the charts - but it's claimed to be "smooth"). In support of that, even though it can go pretty low (PE says 39Hz / 1.5cf), that's a really large box for a 6" woofer.
              More importantly, it's Xmax is VERY low (@ 3mm) - it breaches it @ 6w RMS in that box.

              That said, the T/S parms end up being not THAT important. THAT said, your driver's don't measure up to "spec".
              Your Qts is basically "right on". Given that, F3 will end up fairly proportional to Fs, meaning that YOUR W6 wouldn't make 39Hz, only low 50s probably. Again, not important if used as a mid.

              I usually break in a driver (mostly its suspension - and that's mostly the SPIDER) by CAREfully pushing the cone in and out to Xmax several times using my fingers. You don't want to push off-center and rub (or bind) the voice-coil.

              HA ! - just noticed it's a full-range (that mag made me think it was an HD woofer). It's pretty efficient, and at 89dB, you'd hit about 97dB @ 6w (w/out accounting for baffle-step). Probably not bad for an FR driver that can do 50Hz. (Wonder how'd they do "in-wall"?)

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