- magenta vs. cyan vs. black/silver/gray for optical tracks
- Sound on disc
- Silent films
- optical vs. digital vs. mag
- Amplifiers?
- Sound processors
- Speakers
| Sound format | Type | 70mm? | 35mm? | 16mm? | 8mm? | Super8? | Other gauges? | Notes |
|---|---|---|---|---|---|---|---|---|
| Mono | Optical | x | x | variable density vs. variable area | ||||
| Stereo | Optical | x | ||||||
| Dolby SR | Optical | x | ||||||
| Dolby A | Optical | x | ||||||
| Dolby SR-D | Digital | x | Also called Dolby Digital | |||||
| DTS | Digital | x | x | |||||
| SDDS | Digital | x | ||||||
| Magnetic | Magnetic | x | x | x | x |