HPFs causing serious overshoot

Discussion in 'Mastering' started by Alécio Costa - Brazil, Oct 24, 2002.

  1. Alécio Costa - Brazil

    Alécio Costa - Brazil Well-Known Member

    Hi friends. Until now one had given me a reasonable explanation about serious overshoot with digital equalizers.

    I will explain the situation:
    I am a budget mastering engineer down here in Brazil, although have done some nice tasks...

    Generally I master with the following (very simple) chain:

    Waves Q10 > TC Master X 5 Band Mode > Digi Power dither Level 3 > Waves PAZ..

    or Put L1...

    Whenever I apply one or two HPF´s at my Q10 and with audio files under 0db with NO gain changes at all at itQ10, I hear nasty digital distortion.

    So, I have to lower the Gain input of this Q10 plugin module...

    Other guys have also reported this and people try to convince me that most digital equalizers do that.

    However, my 02R equalizers never show this.

    I am not bashing at Waves anyway, just would like to have a more technical explanation for that.

    If you want to talk about La Place transfer function , poles and zeroes, let us go. I will try to understand / study that either.

    Thanks In advance!
    Nice thursday!

    Eng. Alécio Costa
    Singer/Musician/producer/recording Engineer
    studiodp@terra.com.br
    br.geocities.com/studiodigitalp
    :w:
     
  2. Michael Fossenkemper

    Michael Fossenkemper Distinguished past mastering moderator Well-Known Member

    It has to do with the phase shift and x-over points on the eq. When you kick in the HPF, the phase shift that is created, raises the level slightly around the x-over point and now your eq is clipping. Same thing happens on even the most expensive eq's. For example, I have a weiss eq-1 lp/dyn. If I do the same thing on this eq, it will clipp, if I put the eq in linear phase mode so there isn't any phase shift, It doesn't clip because no boost is being added and there is no phase shift around the HPF. Same thing happens in analog eq's, they just don't clip as hard a plugin's.
     
  3. Alécio Costa - Brazil

    Alécio Costa - Brazil Well-Known Member

    so do you think I will have to re-evaluate the phase at the very bottom end, let us say 0Dc to 40hz?

    What shall we do so besides lowering the input level of that stage?

    Thanks

    BTW.. when are you coming to Brazil my friend?
    :w:
     
  4. Alécio Costa - Brazil

    Alécio Costa - Brazil Well-Known Member

  5. Kev

    Kev Well-Known Member

    If you want to keep using that EQ then you must lower the input level.
    :c:
     
  6. Michael Fossenkemper

    Michael Fossenkemper Distinguished past mastering moderator Well-Known Member

    lower the input level. or use a linear phase eq.
     
  7. Alécio Costa - Brazil

    Alécio Costa - Brazil Well-Known Member

    Yes Michael, I have thought of this new linear phase eq and multiband compressor from Waves...

    thanks
    :w:
     

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