| .WPP | Serif | Ses Dosyaları | WebPlus Project File | Serif WebPlus | Serif |
| .WRK | Cakewalk, Inc. | Ses Dosyaları | Cakewalk Music Project | Cakewalk SONAR | Cakewalk, Inc. |
| .WSQ | UTAU Team | Ses Dosyaları | UTAU File | UTAU | Vocal Synthesizer |
| .WUS | WUSSOFT | Ses Dosyaları | WUTG Tagged Audio File | WUSSoft AutoSound | WUSSOFT |
| .WUT | WUSSOFT | Ses Dosyaları | WUTG Tag File | WUTG Editor | WUSSOFT |
| .WV | David Bryant | Ses Dosyaları | WavPack Audio File | Nullsoft Winamp | Nullsoft |
| .WVC | Open Source | Ses Dosyaları | WavPack Correction File | WavPack | Open Source |
| .WVE | Wondershare Software Co., Ltd. | Ses Dosyaları | Wondershare Filmora Project File | Wondershare Filmora | Wondershare Software Co., Ltd. |
| .X3V | Yamaha Corporation | Ses Dosyaları | Yamaha Motif Audio | Translator Professional | Chicken Systems |
| .XA | Electronic Arts | Ses Dosyaları | The Sims Audio File | Electronic Arts SimCity 4 | Electronic Arts |
| .XAD | Riven the Mage | Ses Dosyaları | eXotic ADlib Sound Format File | Unknown Software | Unknown Developer |
| .XFS | Elabtronics Company | Ses Dosyaları | eRacer Sound File | CoreChart | Elabtronics Company |
| .XI | Starbreeze Studios | Ses Dosyaları | Fasttracker 2 Extended Instrument File | Awave Studio | FMJ-Software |
| .XKR | Sing-Magic | Ses Dosyaları | Sing Magic Karaoke Song | Sing-Magic Karaoke | Sing-Magic |
| .XM | Starbreeze Studios | Ses Dosyaları | FastTracker 2 Extended Module | ModPlug Player | Open Source |
| .XMF | Open Source | Ses Dosyaları | Cal3D XML Mesh File | Cal3DViewer | Open Source |
| .XMI | Object Management Group (OMG) | Ses Dosyaları | XML Metadata Interchange File | Eclipse IDE for Java Developers | The Eclipse Foundation |
| .XMS | Alexander Gross | Ses Dosyaları | Music Studio Project | Alexander Gross Music Studio | Alexander Gross |
| .XMZ | Starbreeze Studios | Ses Dosyaları | FastTracker 2 Extended Module | ModPlug Player | Open Source |
| .XP | Starbreeze Studios | Ses Dosyaları | Fastracker 2 Pattern | Fasttracker | Starbreeze Studios |
| .XPA | SoniqCast, LLC | Ses Dosyaları | SoniqSync Extended Playlist | SoniqSync | SoniqCast, LLC |
| .XPF | Open Source | Ses Dosyaları | Linux MultiMedia Studio Preset File | LMMS | Open Source |
| .XPL | Interscape | Ses Dosyaları | LcdStudio Playlist File | LCDStudio | Interscape |
| .XRNS | Renoise.com | Ses Dosyaları | Renoise Song File | Renoise | Renoise.com |
| .XSB | Microsoft Corporation | Ses Dosyaları | XACT Sound Bank | Microsoft XACT | Microsoft Corporation |
| .XSP | Open Source | Ses Dosyaları | Kodi Smart Playlist File | Kodi | Open Source |
| .XSPF | VideoLAN | Ses Dosyaları | XSPF Playlist File | VLC Media Player | VideoLAN |
| .XT | Derick Rethans | Ses Dosyaları | Xdebug Trace File | Xdebug | Derick Rethans |
| .XWB | Microsoft Corporation | Ses Dosyaları | XACT Wave Bank | Microsoft XACT | Microsoft Corporation |
| .XWC | Starbreeze Studios | Ses Dosyaları | Starbreeze Sound Data | Knights of the Temple | Starbreeze Studios |
| .XWV | Valve | Ses Dosyaları | Valve Xbox360 Audio Data | Valve Source SDK | Valve |
| .YGD | Open Source | Ses Dosyaları | YouGooDai Playlist File | YouGooDai | Open Source |
| .YM | Atari Corporation | Ses Dosyaları | Atari ST Audio File | Nullsoft Winamp | Nullsoft |
| .YNX | Unknown Developer | Ses Dosyaları | Segmax Seqprest Compressed File | Unknown Software | Unknown Developer |
| .Z00 | Casio Computer Co., Ltd. | Ses Dosyaları | Casio WK-3000 Rythm Data | Casio Data Manager | Casio Computer Co., Ltd. |
| .ZAB | VideoLAN | Ses Dosyaları | Zipped Audio Book | VLC Media Player | VideoLAN |
| .ZAF | Zoom Corporation | Ses Dosyaları | Zoom Audio Data | Zoom Player | Inmatrix Media Solutions |
| .ZAX | Zaxcom | Ses Dosyaları | Zaxcom Audio Data | Unknown Software | Unknown Developer |
| .ZEL | Andrew Maclean | Ses Dosyaları | Zel MIDI Source File | Zel | Andrew Maclean |
| .ZPA | zplane.development GmbH & Co. KG | Ses Dosyaları | Vielklang Audio Metadata File | Steinberg Cubase | Steinberg |
| .ZPL | Inmatrix Media Solutions | Ses Dosyaları | Zoom Player Play List | Zoom Player | Inmatrix Media Solutions |
| .ZVD | Zyxel Communications | Ses Dosyaları | ZyXEL Voice File | Zyxel Z-Fax modem Software | Zyxel Communications |
| .ZVR | SAFA Inc. | Ses Dosyaları | SAFA Media Audio File | Microsoft Windows Media Player | Microsoft Corporation |
| .ZYX | Zyxel Communications | Ses Dosyaları | ZyXEL Voice File | Zyxel Z-Fax modem Software | Zyxel Communications |
| ._1 | Interscape | Ses Dosyaları | Tuningwrench Audio Utility Compressed Audio | Tuningwrench | Interscape |
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