Harmonic Distortion in UMC404HD

  1. #11 by June Kim on 1 Week Ago
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    Hi Michael,

    1) The mixer plays the test signal and it is routed into UMC404HD. You wanted the mixer eliminated so I did a loopback test from UMC404HD into itself. UMC404HD's output 1 is playing the test signal and it is routed to the input 1 with a TRS cable. As you can see in the attached screenshot, there is harmonic distortion.

    2) I am using the proprietary driver for UMC404HD, which is also an ASIO driver.

    - Michael Lapke wrote View Post
    Hey June,

    My apologies for not replying to this thread earlier. Honestly I'm not sure why you would be seeing this with TRS vs XLR cable, unless there was an issue with the TRS cables in question. What exactly does the Yamaha Mixer add to the equation? Is there a specific reason why you need to use it with your UMC404HD? Further is there a reason why you're using ASIO drivers instead of the recommended proprietary ones we provide here on our website?

    You could always eliminate the Mixer and try using the UMC drivers to see if it still happens. Beyond that or any of the suggestions CARE provided I'm really not sure what else to recommend for you. Please keep me posted if you are able to make any progress.
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  2. #12 by June Kim on 1 Week Ago
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    and this is the spectrum analysis for the same loopback setting instead with TRS to XLR cable. That is, the output 1 of UMC404HD is connected to a TRS cable and the other end is XLR, which is connected to the input 1 XLR jack.

    As you can see, the same signal level is matched(-20dbFS) for the main test signal at 1kHz and you see much lower harmonic distortion.

    - Michael Lapke wrote View Post
    Hey June,

    My apologies for not replying to this thread earlier. Honestly I'm not sure why you would be seeing this with TRS vs XLR cable, unless there was an issue with the TRS cables in question. What exactly does the Yamaha Mixer add to the equation? Is there a specific reason why you need to use it with your UMC404HD? Further is there a reason why you're using ASIO drivers instead of the recommended proprietary ones we provide here on our website?

    You could always eliminate the Mixer and try using the UMC drivers to see if it still happens. Beyond that or any of the suggestions CARE provided I'm really not sure what else to recommend for you. Please keep me posted if you are able to make any progress.
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  3. #13 by Ken Mitchell on 1 Week Ago
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    - June Kim wrote View Post
    and this is the spectrum analysis for the same loopback setting instead with TRS to XLR cable. That is, the output 1 of UMC404HD is connected to a TRS cable and the other end is XLR, which is connected to the input 1 XLR jack.

    As you can see, the same signal level is matched(-20dbFS) for the main test signal at 1kHz and you see much lower harmonic distortion.
    Hi June,

    I got the same results you did in this configuration except I used a GXJ-235 TRS-XLR adapter since I don't have a TRS-XLR cable.

    One thing I noticed of interest and that is I'm only seeing the 2nd harmonic using the TRS-TRS loopback from 404HD output to input. When using an external signal generator I see a 2nd through 5th harmonic.

    See this image: https://forum.musictri.be/attachment...1&d=1517072540

    I don't know how relevant that is but thought it was worth mentioning.

    Ken

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  4. #14 by Michael Lapke on 1 Week Ago
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    - June Kim wrote View Post
    Hi Michael,

    1) The mixer plays the test signal and it is routed into UMC404HD. You wanted the mixer eliminated so I did a loopback test from UMC404HD into itself. UMC404HD's output 1 is playing the test signal and it is routed to the input 1 with a TRS cable. As you can see in the attached screenshot, there is harmonic distortion.
    Hoping you can clarify about this:

    How are you getting a test signal into the UMC404HD if you aren't using the mixer? You said you're looping the output 1 signal back into input 1, but then how are you feeding this test tone into your UMC404HD?

    Again, as I said there's not going to be a whole lot that I can suggest outside of what CARE has already told you. At this point I'm just trying to determine that specifics to what causes this for you and hope that might shed some light on how to overcome it. So far the XLR vs TRS seems to be the biggest key factor so far, but maybe there's something we're missing here.

    Last edited by Michael Lapke; 1 Week Ago at 03:56 PM.
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