Back to overview Documentation version 9.23

Absolute Highs section

High frequency reconstruction.

Absolute Highs reconstructs missing high frequencies in recordings. For example, if a file has been recorded at 22 kHz instead of 44, there's no audio above 11 kHz, and Absolute Highs can generate a reasonable approximation of what should have been there.

Beside this, it can also be useful for old music, which doesn't have much highs to begin with.

Absolute Highs panel

Absolute Highs settings.

  • Absolute Highs
    Enables Absolute Highs.

  • Follow Delossifier (off if no MPEG)
    Follows the detected lowpass level from the Delossifier.

    The Delossifier is not very good at reconstructing high frequencies, use this setting to make Absolute Highs take over above the detected lowpass frequency.

    If the Delossifier detects no MPEG audio, enabling this setting will automatically disable Absolute Highs.

  • Before multibands
    Location of Absolute Highs in the processing chain.

  • Effect strength
    The effect strength of Absolute Highs.

    Absolute Highs estimates how much highs should have been present. Lowering this slider reduces the effect that it has on the audio.

  • Band width
    Detection band width.

    Setting this very low causes "sqeeky" highs, and increases the CPU load. Setting this very high makes the reconstructed highs more noisy.

  • Band distance
    Detection band overlap.

    Setting this lower makes the reconstruction a bit better, at the cost of increasing the CPU load.

  • Maximum generation above
    Don't reconstruct any highs below this frequency.

  • Slope up to
    Do maximum reconstruction above this frequency.

  • Peak Distance Maximum
    Detection of harmonics of an instrument can only take place if they are less than this far apart from each other.

  • Block on startup
    Perform heavy calculations at once on startup or settings changes.

    Turning this on will briefly block the processing until the calculations have been performed.

    Turning this off will do the calculations during normal processing, which means that after startup or after changing a setting, the filter takes a few seconds to become active.

  • 4x oversampling
    Oversample the audio to avoid aliasing effects.

    This sounds slightly better, but increases the CPU load a lot.

  • 1 band (off = 160)
    Very light-weight, but noise version of the algorithm.

Input spectrum panel

Shows the input spectrum before Absolute Highs.

Output spectrum panel

Shows the output spectrum after Absolute Highs.

Gating panel

Noise control settings.

  • Threshold (gate)
    Filters out very soft noisy sounds that Absolute Highs generates.

    This can be useful for example for speech, where you want the high part of S sounds to be reconstructed, but you might not want to get noisy harmonics on everything.