| nsla | Nero Video Audio Data |
| nsp | KayPentax CSL Audio |
| nst | Noise Tracker Music Module |
| ntn | NOTION Song |
| ntp | NovoTrade Packer Music |
| ntw | NoteWorthy Composer Music |
| nus3audio | Super Smash Bros NUS3 Audio Data |
| nus3bank | Super Smash Bros Nus3bank Audio Archive |
| nvf | Creative Labs NOMAD II Audio |
| nwc | NoteWorthy Composer Music |
| nwctxt | NoteWorthy Composer Text |
| nw_ | Compressed NoteWorthy Composer Music |
| nxt | NeXTSTEP Sound File |
| o01 | Typhoon OS Voice Data |
| obw | Superior Drummer Sound File |
| obw | Toontrack Superior Drummer Audio |
| ocdf | OneClickDigital Audio Book |
| odd | Coby Voice Recorder Data |
| odm | OverDrive Media Data |
| ofg | OptimFROG Dualstream Audio |
| ofr | OptimFROG Lossless Audio |
| ofs | OptimFROG Dualstream Audio |
| oga | Ogg Vorbis Compressed Audio |
| ogg | Ogg Vorbis Compressed Audio |
| oggstr | Godot Engine OGG Audio Data |
| ogx | Ogg Vorbis Compressed Audio |
| okt | Oktalyzer Music Module |
| olv | OnLive! Traveler Sound |
| oma | Sony ATRAC3 Compressed Audio |
| omg | Sony ATRAC3 Compressed Audio |
