iZotope MBIT+ Dither

Choose Process > iZotope MBIT+ Dither to convert sound files to different bit depths and apply dithering.

Because the signal-to-noise ratio decreases when you decrease the bit depth of a file, you should maximize the volume of the sound file using the Volume or Normalize functions before performing the conversion.


  1. Choose Process > iZotope MBIT+ Dither.

  2. Choose a setting from the Preset drop-down list, or adjust the controls as needed.

    Item

    Description

    Bit depth

    Specify the sample rate to which the sound file will be converted.

    Increasing a file's sample rate cannot improve the quality of the existing audio, but does allow higher resolution for processing.

    Dither mode

    Choose a setting from the drop-down to choose the type of dithering that will be applied to mask quantization noise.

    • Type 1: Uses a traditional rectangular probability distribution function.

    • Type 2: Uses a traditional rectangular probability distribution function.

    • MBIT+: Uses a proprietary algorithm to offer superior results for all types of source material.

    Noise shaping

    Choose a setting from the drop-down list to control the amount of noise shaping that will be applied.

    When Type 1 or Type 2 is selected in the Dither mode drop-down list, the following settings are available:

    • None: No noise shaping is applied.

    • Simple: A high-pass filter is applied to the dither noise.

    • Clear: Aggressively moves dither noise toward the Nyquist frequency.

    • Psych5: Uses a fifth-order filter to move dither noise away from audible frequency bands.

    • Psych9: Uses a ninth-order filter to move dither noise away from audible frequency bands.

    When MBIT+ is selected in the Dither mode drop-down list, you can choose a setting from the Noise shaping drop-down list to control the amount of noise shaping applied. Increased settings will provide more audible noise suppression at the expense of a higher noise floor.

    Dither bits/amount

    When Type 1 or Type 2 is selected in the Dither Mode drop-down list, you can choose a setting from the Dither Bits drop-down list to choose whether you want to use 1 or 2 dither bits. 1 works well for most applications.

    When MBIT+ is selected in the Dither mode drop-down list, you can choose a setting from the Dither amount drop-down list to control the amount of dithering applied. Normal works well for most applications. The None and Low settings can leave some nonlinear quantization distortion or dither noise modulation behind. The High setting can eliminate nonlinear quantization distortion at the expense of a higher noise floor.

    Auto blank

    Allows you to scale the cutoff frequency of the plug-in's low-pass filter from the Nyquist frequency.

    Typical values are near 1. Higher values will offer a flatter pass-band, and lower values will offer better aliasing suppression.

    Minimize peaks

    Select this check box if you want to suppress peaks in the dither noise signal.

    Silence harmonics

    Select this check box if dithering distorts the timbre of your audio. When the check box is selected, harmonic quantization distortion is moved away from the overtones of audible frequencies.

  3. Click the Process button.