• Optical Tracks
    • Mono
      • variable density vs. variable area
    • SR
    • Dolby A
    • magenta vs. cyan vs. black/silver/gray


  • Digital
    • SRD / Dolby Digital
    • DTS
    • SDDS


  • Magnetic


  • Sound on disc
  • Silent films
  • optical vs. digital vs. mag
  • Amplifiers?
  • Sound processors
  • Speakers