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DSP Effects Grabber and Fade interact poorly (bug?)

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  • GiacomoGo
    • Aug 2006
    • 48

    DSP Effects Grabber and Fade interact poorly (bug?)

    So here's what I did, and the unexpected results using dBpa MC & Audacity to view results of conversions.
    Result *3 seems to indicate a bug in the interaction of the Grabber and Fade DSP Effects:

    Objective: Cut some trailing noise off the end of a track ripped from CD to MP3 VBR standard (-V 2)

    1 - converted .mp3 file, with adding *only* the Grabber DSP Effect to take 2min 25sec from the start.
    Result: sounds good & looks (in Audacity) like the desired grab.

    2 - converted result of (1), with adding *only* the Fade DSP Effect to Fade Out over the final 2000 milliseconds.
    Result: sounds good & looks (in Audacity) like the desired grab and fade.

    3 - Tried to do this instead in a single step. Convert original track including trailing noise, with adding *both* the Grabber and next the Fade Out DSP Effects (both as configured in (1) and (2)).

    PROBLEM Result: track sounds horrible (amplified way too high, distorted) & looks overly amplified and distorted in Audacity.

    So my conclusion is that these 2 DSP Effects interact in some unexpected way.
    I would expect that the combined effects (3) should produce an identical .mp3 file as the two step process (1) + (2).

    Is this a bug, or do I need to understand some clear limitation in combining DSP Effects ... before inadvertently I destroy my mp3 library.
  • Spoon
    Administrator
    • Apr 2002
    • 44178

    #2
    Re: DSP Effects Grabber and Fade interact poorly (bug?)

    Using R14.4 with the latest DSP effects?
    Spoon
    www.dbpoweramp.com

    Comment

    • GiacomoGo
      • Aug 2006
      • 48

      #3
      Re: DSP Effects Grabber and Fade interact poorly (bug?)

      Originally posted by Spoon
      Using R14.4 with the latest DSP effects?
      Confirmed. According to dBpoweramp Configuration:
      dBpa MC Reference Release 14.4
      DSP Effects Release 9

      ---------------------------
      dBpoweramp
      ---------------------------
      All latest programs and codecs are installed.
      ---------------------------
      OK
      ---------------------------

      Comment

      • GiacomoGo
        • Aug 2006
        • 48

        #4
        Re: DSP Effects Grabber and Fade interact poorly (bug?)

        I had trouble reproducing the amplification/distortion. I finally did -- seems related to the track, rather than a general issue.

        However, the "Fade" DSP Effect does seem to *always* ignore the prior "Grabber" settings.
        Looks like "Fade" calculates when it should start/stop the fade without considering whether a prior "Grabber" reduces the track length.
        Just a guess.

        As far as the amplification/distortion when combining Grabber + Fade, it seems to depend on the "loudness" and perhaps variability of the recording:

        Here's a track that works OK (but no fade, as guessed above):

        [ nb: grabbed clip is smaller filesize than original ]

        Here's a track that causes dBpa MC to amplify/distort the grabbed track (and still no fade):

        [ nb: grabbed clip is actually larger than original ]
        Last edited by GiacomoGo; October 27, 2013, 05:32 PM.

        Comment

        • GiacomoGo
          • Aug 2006
          • 48

          #5
          Re: DSP Effects Grabber and Fade interact poorly (bug?)

          Just hoping for some feedback. Am I doing something wrong, or is MC?

          Comment

          • Spoon
            Administrator
            • Apr 2002
            • 44178

            #6
            Re: DSP Effects Grabber and Fade interact poorly (bug?)

            It looks like a bug, however if you include the DSP effect 'Non Live' it should work.
            Spoon
            www.dbpoweramp.com

            Comment

            • GiacomoGo
              • Aug 2006
              • 48

              #7
              Re: DSP Effects Grabber and Fade interact poorly (bug?)

              Originally posted by Spoon
              It looks like a bug, however if you include the DSP effect 'Non Live' it should work.
              Yep, this "Force Non-Live" effect let's MC do the individual steps in sequence, which produces the right results. Thanks.

              Comment

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