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  • ECM 8000 Calibration Tests

    Sorry this took so long, but I have my test system running again and I can finally show the results.

    I use an ECM 8000 test mic and it has been sent to both Kim Girardin [email protected] and Herb Singleton [email protected] for testing. Herb's test cost $50, Kim's test cost $40.

    Herb's test (dated 10/14/2008) runs from 20 Hz to 20 kHz (I used his moving average frd file, first data point is 27.8 Hz, last data point is 20099.1 Hz. His narrow band response file runs from 19 Hz to 20099.1 Hz.)

    Kim's test (dated 01/20/2009) runs from 10 Hz to 46 kHz.

    Neither file contains phase response data.

    The attached files are the calibration files displayed in Sound Easy (1 dB/unit on the Y axis). The files were tailed as accurately as I could to cover the 5 Hz to 50 kHz range displayed. The phase response of both was generated using the Hilbert transform function in Sound Easy. The first attachment is Herb's result, the second is Kim's result. The results are very similar, with the exception of the 10 to 100 Hz region and the roll-off after about 11 kHz. I tend to trust Kim's results, the dead flat bass response from Herb's measurement may be a bit optimistic, or the mic's response could have changed by the time Kim measured it.

    I use Kim's file, I like having the extended response for HD sweeps.
    Attached Files
    Jay T
    http://sites.google.com/site/lhwidgetssite/home

  • #2
    Re: ECM 8000 Calibration Tests

    I see you have a newer ECM8000 there. The old ones only had about a 1-1.5 db rise at the top, a large difference from the current 6-7 db rise.

    Did your mic ship with an updated response curve printed out and stuck in the box? I heard that some have.

    Comment


    • #3
      Re: ECM 8000 Calibration Tests

      Originally posted by lhwidget View Post
      or the mic's response could have changed by the time Kim measured it.
      :D

      Thanks for posting this info, Jay. It's good to see their results match from 100 Hz to 20 kHz. My ECM8000 was measured by KG three weeks earlier than yours. Mine is very different in the top octave. I think yours has a typical ECM8000 response. Mine is nearly flat up to 10 kHz with only a 0.5 db rise around 4 k to 8 kHz, and it begins to drop from 9 kHz. I wonder if this will change as I use it---will it "break in?"

      -jAy

      Comment


      • #4
        Re: ECM 8000 Calibration Tests

        John,
        No, it didn't. The only response graph was printed on the box. That one shows a small hump at 10 kHz and a larger hump at 20 kHz. I bought mine in March of 2008. I found the problem comparing my ND20FB-4 response measurements to your measurements.

        Jay,
        I really don't know, but it seems unlikely. Don't these mics use a capsule that responds directly to pressure, that is, the diaphram doesn't really move like the diaphram of a moving coil mic?
        Jay T
        http://sites.google.com/site/lhwidgetssite/home

        Comment


        • #5
          Re: ECM 8000 Calibration Tests

          I have a Liberty Instruments mic (made by Kim G) which also uses the panasonic electret capsule. Kim calibrated it when it was new and then recalibrated it after 2-3 years and any response changes were so minor that they were well within the margin of error for the calibration.

          Dennis

          Comment


          • #6
            Re: ECM 8000 Calibration Tests

            Thanks Dennis
            Jay T
            http://sites.google.com/site/lhwidgetssite/home

            Comment


            • #7
              Re: ECM 8000 Calibration Tests

              I've been pretty critical of Superlux (OEM for the Behringer) but I read a paper lately that changed my mind. The hump at 10K seems to be built into the Panasonic WM-61 capsule that replaced the older WM-60. The flat ones people occasionally still buy are probably old-stock WM-60 models. The guy in the paper built 8 mics using the WM-61, half wired stock and half with the Linkwitz mod. All the stock ones had the same hump within a dB or so although the hump was smaller with the mod. Distortion was also lower with the mod. He was using a B&K to compare to.

              PS, Herb says he can do down to 5Hz at no extra charge if you request it but I don't know if he can do above 24K. I've been taking the opportunity to pick his brain a little over at HTS where I'm a noob and some of you might want to join in. Seems like he knows a lot.

              http://www.hometheatershack.com/foru...n-service.html
              Dennis

              Comment


              • #8
                Re: ECM 8000 Calibration Tests

                Both of mine are going to Kim when I get home, and neither came with a response curve other than the generic one on the cardboard liner. Very good information!

                Cheers / Robert

                Comment


                • #9
                  Re: ECM 8000 Calibration Tests

                  Herb's a nice guy, I enjoyed discussing things with him. Unless he's changed his set-up, he can't measure above 20 - 24 kHz. I didn't think to ask him to run my test down to 5 Hz, it's nice to know he can.
                  Jay T
                  http://sites.google.com/site/lhwidgetssite/home

                  Comment


                  • #10
                    Re: ECM 8000 Calibration Tests

                    All:

                    I was referring to the difference in mics, I have 2 purchased at different times. I run SE 10Hz - 20Khz, so either service would be fine for me.

                    Robert

                    Comment


                    • #11
                      Re: ECM 8000 Calibration Tests

                      Originally posted by robert View Post
                      I run SE 10Hz - 20Khz, so either service would be fine for me.
                      I think it's still worthwhile to extend the tails like Jay did. The HBT gives you a mucked up minimum phase if you don't. I played with it a bit today and there was like a 70 degree phase error at 20 Hz if you chopped a 1 Hz file off at 20 Hz and then ran the HBT.
                      Dennis

                      Comment


                      • #12
                        Re: ECM 8000 Calibration Tests

                        Originally posted by jkrutke View Post
                        I see you have a newer ECM8000 there. The old ones only had about a 1-1.5 db rise at the top, a large difference from the current 6-7 db rise.

                        Did your mic ship with an updated response curve printed out and stuck in the box? I heard that some have.

                        My two mics had the response curve printed, not in the cardboard box, but surrounding the plastic box the mic comes in.

                        And it's basically identical to what Herb Singleton measured on my mics. (6 dB rise on top).
                        Line Array: IDS-25 Clone, FE-83.
                        2-2.5 Way:
                        Zaph Audio's winning entry: ZA5+SB29. - Microliths: RS125+RS28. - Small Bangs: TB W4-1658SB+SEAS 27TBFC/G. - Monoliths: Peerless 830884+SEAS 27TBFC/G.
                        3-3.5 Way:Miniliths: SEAS P21/CA21REX+Neo8 PDR+Neo3 PDR. - Megaliths: 2xDayton RS270+2xT-B W4-1337SB+SB29. - ZDT3.5 +: 2xDayton RS180+Dayton RS52+Vifa DQ25. Reflexos: OB 4xDayton RS150 + Neo3 PDR.

                        Comment


                        • #13
                          Re: ECM 8000 Calibration Tests

                          Originally posted by fjhuerta View Post
                          My two mics had the response curve printed, not in the cardboard box, but surrounding the plastic box the mic comes in.

                          And it's basically identical to what Herb Singleton measured on my mics. (6 dB rise on top).
                          Does the rise at the top mean it is too sensitive at higher f, or vice versa?

                          Comment


                          • #14
                            Re: ECM 8000 Calibration Tests

                            Comment


                            • #15
                              Re: ECM 8000 Calibration Tests

                              Originally posted by brianpowers27 View Post
                              Does the rise at the top mean it is too sensitive at higher f, or vice versa?
                              Too sensitive. The cal file contains the actual frequency response of the mic. Sound Easy subtracts the response in the cal file from the results.
                              Jay T
                              http://sites.google.com/site/lhwidgetssite/home

                              Comment

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