Wierd looking wave forms...

Discussion in 'Microphones (live or studio)' started by Mastergod, Oct 17, 2009.

  1. Mastergod

    Mastergod Guest

    I don´t know if this is has something to do with with Logic, or if this is related to my recording(but, which is more likely).

    This shows the wave form for one of the drum overheads:


    Does anyone have an ide what causes this kind of wave form. It does look clipped (but it is not as I understand) at the bottom and long tiny transients at the top. I have not used any compression when recording, but the preamp has the possibility to change impedance.

    Art preamp --> Presonus Firepod --> Logic Pro.

    All the best, Mastergod.
  2. Kev

    Kev Well-Known Member

    Nov 13, 2001
    I don't know your answer but I'd be temped to swap out a components at a time

    change mic
    change pre-amp
    change input to the firepod

    one at a time and see if you can identify the one unit
    that could be at fault
    mic element that has part movement in one direction
    pos/neg issue in the ART
    same goes for the interface

    does this flatness happen on other sources ?
  3. Boswell

    Boswell Moderator Distinguished Member

    Apr 19, 2006
    Home Page:
    Try interchanging the XLR plugs from the OH mics at the input to the pre-amp. If the limited negative excursion stays on that channel, you have a pre-amp problem. If it moves to the other channel, narrow it down to a mic or cable problem by swapping the XLR connectors at the OH mics.

    I have seen this sort of effect when a phantom power blocking capacitor goes leaky and biases the pre-amp input stage off to near one rail. Internally the pre-amp will only swing a limited amount in one direction, but because of a.c. coupling at the output, it still appears to be centred around zero.

    Eliminate the mics and cables first.

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