| xann | XANN Packer Audio Data |
| xfs | eRacer Sound |
| xgc | Binary eXtended Genesis Music |
| xgm | eXtended Genesis Music |
| xi | FastTracker 2 Instrument |
| xiz | ZynAddSubFX Instrument File |
| xkr | Sing-Magic Karaoke Song |
| xm | FastTracker 2 Music Module |
| xma | Xbox 360 Native Audio |
| xmf | Extensible Music Format File |
| xmf0 | Extensible Music Format File |
| xmf1 | Extensible Music Format File |
| xmi | Extended MIDI Song |
| xms | XMS Tracker Module |
| xmz | ZynAddSubFX Master File |
| xmz | FastTracker 2 Extended Module |
| xopus | Exient XGS OPUS Audio Data |
| xp | FastTracker 2 Pattern |
| xpm | Akai MPC Software Program |
| xrni | Renoise Instruments Data |
| xrns | Renoise Song |
| xsb | XACT Sound Bank |
| xsm | eXtra Simple Music Data |
| xsml | iRomplerMap Audio Data |
| xspf | XML Shareable Playlist File |
| xt | Fast Tracker 2 Music Track |
| xvag | Sony PlayStation 3 Audio File |
| xwb | XACT Wave Bank |
| xwm | Microsoft xWMA Compressed Audio |
| xwma | Microsoft xWMA Compressed Audio |