PDF (adobe.com)

Change 5.1 audio to stereo or mono

  1. Choose Edit > Preferences > Audio (Windows) or Premiere Pro > Preferences > Audio (Mac OS).
  2. Choose a 5.1 Mixdown Type from the pop‑up menu, and click OK.
    Note: To preserve the integrity of left/right channel assignments, you may want to avoid using downmix options that include the LFE channel.