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Impedance Measurement / Computer Problem

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  • Impedance Measurement / Computer Problem

    I have posted this at DIYaudio and at the Soundeasy Board also but there seem to be several sharp minds here that I don't see there so I apologize to those who see both posts.
    I have two set ups with which I measure loudspeakers with computer and software, one at home and one at my office. Both have dedicated Windows XP SP3 computers that run SoundEasy v19 without a problem. I have the ARTA software on both, as well. Both use the same jig. I have 3 different amplifiers. Same soundcard on each (Creative XFi Xtreme Gamer).

    The problem is in testing a resistor (metal film - 20 ohm) I am getting a strange high pass effect on the office computer. This shows in doing a frequency response on the calibration setting, as well. Neither shows on the home computer. I switched out the jigs and amps and it is clearly an effect of the office computer. It does not show up when running LIMP in Pink Noise or using a Sine Wave Test. So it is isolated to the SE program only on my office computer.

    My office has fluorescent lighting so I tested that computer at home (incandescent) and the problem followed the computer. I only switched out the computer and explored distances from the monitor thinking that perhaps this impacted things but it had no impact.
    I switched out the leads, as well. At home, no problems regardless of which leads were used; in the office, all produced similar issues with a high pass function.

    The settings are the same for SE on both computers. When I ran a direct loop from the output to the input using RMAA, it does not show up so the soundcard appears to be doing just fine. The only thing that I can think of from a hardware perspective is perhaps the output caps on the soundcard are having problems under load, but this is unlikely given the expected results obtained with Sine and Pink Noise tests.

    I unloaded the virus program and still no change.

    The computer is already streamlined with recommendations made by George Soong.

    I would welcome any guidance for further investigation. I uploaded the Soundeasy Screenshots. Will do the LIMP shots in another entry.

    Thnx, Jay

    Attached Files
    Our greatest glory lies not in never falling, but in rising each time we fall.

  • #2
    Re: Impedance Measurement / Computer Problem

    Here are the LIMP files, as promised. Any suggestions would be welcomed. I have been doing measurements for a long time and this is the first time I have run into this...of course, it is not a computer that I used in the past but it seems like since LIMP does fine, so should Soundeasy, if it is a hardware issue. So this leads me to believe it is some sort of software conflict but I don't know where to look.

    Attached Files
    Our greatest glory lies not in never falling, but in rising each time we fall.