| .S1A | Oracle Corporation | Ficheiros de Áudio | Sealed Acrobat Document | Unsealer | Oracle Corporation |
| .S1M | Yamaha Corporation | Ficheiros de Áudio | Yamaha EX5 Waveform Data | Awave Studio | FMJ-Software |
| .S1Y | Yamaha Corporation | Ficheiros de Áudio | Yamaha EX-series Synthesizer Internal Voice And Performance Data | Unknown Software | Unknown Developer |
| .S3I | Open Source | Ficheiros de Áudio | Scream Tracker 3 Instrument | Scream Tracker 3 | Future Crew |
| .S3M | FMJ-Software | Ficheiros de Áudio | S3M | ModPlug Player | Open Source |
| .S3Z | Future Crew | Ficheiros de Áudio | Compressed Scream Tracker 3 Module | ModPlug Player | Open Source |
| .S48 | Jutel | Ficheiros de Áudio | Jutel RadioMan MPEG2 Audio | Jutel RadioMan | Jutel |
| .S7 | Avid Technology | Ficheiros de Áudio | Sibelius Music Notation | Avid Sibelius | Avid Technology |
| .SA2 | Nullsoft | Ficheiros de Áudio | Suprise! Adlib Tracker Music Module | Nullsoft Winamp | Nullsoft |
| .SAF | DeLorme | Ficheiros de Áudio | Street Atlas USA Map File | DeLorme Street Atlas USA | DeLorme |
| .SAG | Sagem Communication (SAFRAN Group) | Ficheiros de Áudio | Sagem Ringtone Format | Unknown Software | Unknown Developer |
| .SAP | Atari Corporation | Ficheiros de Áudio | Atari SAP Music File | Nullsoft Winamp | Nullsoft |
| .SB | MIT Media Lab | Ficheiros de Áudio | Scratch Project File | MIT Scratch | MIT Media Lab |
| .SBG | Open Source | Ficheiros de Áudio | SBaGen Binaural Beat File | SBaGen | Open Source |
| .SBI | Creative Technology Ltd. | Ficheiros de Áudio | Sound Blaster Instrument | Virtual Sound Blaster | Creative Technology Ltd. |
| .SBK | SwishZone | Ficheiros de Áudio | SWiSH Project Backup File | SWiSH Max | SwishZone |
| .SBM | Keen Software House | Ficheiros de Áudio | Space Engineers Mod File | Space Engineers | Keen Software House |
| .SC2 | EA Maxis | Ficheiros de Áudio | SimCity 2000 City File | Maxis SimCity 2000 | EA Maxis |
| .SD | Various Developers | Ficheiros de Áudio | Sound Designer Audio File | Awave Studio | FMJ-Software |
| .SD2 | Avid Technology | Ficheiros de Áudio | Sound Designer II File | Apple iTunes | Apple |
| .SD2F | Avid Technology | Ficheiros de Áudio | Sound Designer II File | Apple iTunes | Apple |
| .SDK | Autodesk, Inc. | Ficheiros de Áudio | AutoSketch Drawing | AutoSketch | Autodesk, Inc. |
| .SDP | Oracle Corporation | Ficheiros de Áudio | StarOffice Presentation File | Apache OpenOffice | Apache Software Foundation |
| .SDS | Oracle Corporation | Ficheiros de Áudio | OpenOffice.org Chart | Apache OpenOffice | Apache Software Foundation |
| .SDT | Intuit, Inc. | Ficheiros de Áudio | QuickBooks Data File | Intuit QuickBooks Pro | Intuit, Inc. |
| .SDV | Pinnacle Systems Inc. | Ficheiros de Áudio | Studio DV Project File | Pinnacle Studio | Corel |
| .SDX | Kivuto | Ficheiros de Áudio | Kivuto Secure Download Manager File | Kivuto Secure Download Manager | Kivuto |
| .SEG | SEG (The Society of Exploration Geophysicists) | Ficheiros de Áudio | SEG-2 Data File | Unknown Software | Unknown Developer |
| .SEQ | PG Music Inc | Ficheiros de Áudio | PowerTracks Pro Audio Project File | PowerTracks Pro Audio | PG Music Inc |
| .SES | Adobe Systems Incorporated | Ficheiros de Áudio | Audition Session File | Adobe Audition | Adobe Systems Incorporated |
| .SE_ | Cakewalk, Inc. | Ficheiros de Áudio | CakeWalk Pro Compressed Audio File | Cakewalk Pro | Cakewalk, Inc. |
| .SF | Institut de Recherche et de Coordination Acoustique/Musique (IRCAM) | Ficheiros de Áudio | IRCAM Sound File | Awave Studio | FMJ-Software |
| .SF2 | E-mu Systems | Ficheiros de Áudio | SoundFont 2 Sound Bank | Awave Studio | FMJ-Software |
| .SFAP0 | Magix Software GmbH | Ficheiros de Áudio | Sound Forge Pro Audio Proxy File | MAGIX Vegas | Magix Software GmbH |
| .SFK | Magix Software GmbH | Ficheiros de Áudio | Sound Forge Pro Audio Peak File | MAGIX Vegas | Magix Software GmbH |
| .SFL | Magix Software GmbH | Ficheiros de Áudio | Sound Forge Pro Sound Data File | MAGIX Vegas | Magix Software GmbH |
| .SFPACK | Megota Software | Ficheiros de Áudio | Packed SoundFont File | SFPack | Megota Software |
| .SFR | Sonic Foundry | Ficheiros de Áudio | Sonic Foundry Sample Resource File | Awave Studio | FMJ-Software |
| .SFS | Open Source | Ficheiros de Áudio | Squashfs File Archive | 7-Zip | Igor Pavlov |
| .SFZ | Cakewalk, Inc. | Ficheiros de Áudio | SFZ Format File | sforzando | Plogue Art et Technologie |
| .SGW | n-Track | Ficheiros de Áudio | n-Track Studio Packed Song | n-Track Studio | n-Track |
| .SHN | Tony Robinson | Ficheiros de Áudio | Shorten Compressed Audio File | Nullsoft Winamp | Nullsoft |
| .SIB | Avid Technology | Ficheiros de Áudio | Sibelius Score | Avid Sibelius | Avid Technology |
| .SID | Valve | Ficheiros de Áudio | Steam Game Data Backup File | Steam | Valve |
| .SIP | Chris S. Craig | Ficheiros de Áudio | ScopeTrax Compressed Sample File | ScopeTrax | Chris S. Craig |
| .SJ | Blue Ribbon SoundWorks | Ficheiros de Áudio | SuperJAM Audio File | SuperJAM | Blue Ribbon SoundWorks |
| .SLP | Magix Software GmbH | Ficheiros de Áudio | SpectraLayers Pro Project | SpectraLayers Pro | Magix Software GmbH |
| .SLX | MathWorks | Ficheiros de Áudio | MathWorks Simulink Model | Simulink | MathWorks |
| .SLY | GNU Project | Ficheiros de Áudio | Lilypond Guitar File | LilyPond | GNU Project |
| .SMA | Don Ho | Ficheiros de Áudio | C/C++ Source Code File | MacroMates TextMate | MacroMates |
| .SMF | Oracle Corporation | Ficheiros de Áudio | StarMath Formula File | Apache OpenOffice | Apache Software Foundation |
| .SMP | MakeMusic, Inc. | Ficheiros de Áudio | SmartMusic Performance File | SmartMusic | MakeMusic, Inc. |
| .SN | Bluemoon Interactive | Ficheiros de Áudio | Sound Club Editor Compressed Song | Sound Club | Bluemoon Interactive |
| .SN2 | Tom Ehlert Software | Ficheiros de Áudio | Drive Snapshot Second Differential Backup | Tom Ehlert Drive Snapshot | Tom Ehlert Software |
| .SNC | Swiftpage, Inc. | Ficheiros de Áudio | ACT! E-mail/folder Synchronization File | Act! | Swiftpage, Inc. |
| .SND | Open Source | Ficheiros de Áudio | Sound File | Microsoft Windows Media Player | Microsoft Corporation |
| .SNG | Korg | Ficheiros de Áudio | Korg Trinity Song File | Alchemist | SourceForge |
| .SNS | FFmpeg team | Ficheiros de Áudio | SNS Video Game Audio File | FFmpeg | FFmpeg team |
| .SON | Open Source | Ficheiros de Áudio | Notator SL Audio File | Apple Logic Pro | Apple |
| .SONG | Naive Solutions | Ficheiros de Áudio | AudioSauna Song File | Naive Solutions AudioSauna | Naive Solutions |
| .SONIC | Sonic Solutions | Ficheiros de Áudio | DigitalMedia Project File | Roxio Creator NXT Pro 5 | Roxio |
| .SOU | LucasArts Entertainment Company, LLC | Ficheiros de Áudio | Lucas Arts Sound Data | Dragon UnPACKer | Open Source |
| .SPH | National Institute of Standards and Technology (NIST) | Ficheiros de Áudio | NIST SPHERE Audio File | SoX | Open Source |
| .SPM | Corel | Ficheiros de Áudio | Corel WordPerfect Data | Corel WordPerfect | Corel |
| .SPS | IBM | Ficheiros de Áudio | SPSS Program File | IBM SPSS | IBM |
| .SPU | Atari Corporation | Ficheiros de Áudio | Spectrum 512 Image | Lemkesoft GraphicConverter | Lemkesoft |
| .SPX | Xiph.Org | Ficheiros de Áudio | Ogg Vorbis Speex File | Microsoft Windows Media Player | Microsoft Corporation |
| .SRI | Nuance | Ficheiros de Áudio | Dragon NaturallySpeaking Audio Data File | Dragon NaturallySpeaking | Nuance |
| .SS3 | Unknown Developer | Ficheiros de Áudio | Singer Song Writer Audio File | Unknown Software | Unknown Developer |
| .SSM | RealNetworks | Ficheiros de Áudio | Standard Streaming Metafile | RealPlayer | Realtime Technologies |
| .STI | Oracle Corporation | Ficheiros de Áudio | StarOffice Presentation Template | Apache OpenOffice | Apache Software Foundation |
| .STM | Microsoft Corporation | Ficheiros de Áudio | Exchange Streaming Media File | Microsoft Exchange Server | Microsoft Corporation |
| .STW | Oracle Corporation | Ficheiros de Áudio | StarOffice Document Template | Apache OpenOffice | Apache Software Foundation |
| .STX | Unknown Developer | Ficheiros de Áudio | Scream Tracker Music Interface Kit File | CocoModX | Open Source |
| .STY | Jørgen Sørensen / Jososoft | Ficheiros de Áudio | Yamaha/Korg Keyboard Style | Style Fixer | Jørgen Sørensen / Jososoft |
| .STZ | Future Crew | Ficheiros de Áudio | Screamtracker 2 Module | Scream Tracker 3 | Future Crew |
| .SUN | Sun Microsystems | Ficheiros de Áudio | Sun Raster Graphic File | GIMP | The GIMP Development Team |
| .SVD | Polytec | Ficheiros de Áudio | Scanning Vibrometer Data File | Polytec PSV Software | Polytec |
| .SVQ | Roland Corporation | Ficheiros de Áudio | Roland Sequencer File | Awave Studio | FMJ-Software |
| .SVX | The Survex Project | Ficheiros de Áudio | Survex Cavern Data File | Microsoft Notepad | Microsoft Corporation |
| .SW | Waveform Software | Ficheiros de Áudio | Signed Word Audio File | Waveform SoX Wrap | Waveform Software |
| .SWA | Adobe Systems Incorporated | Ficheiros de Áudio | Shockwave Audio | Adobe Director | Adobe Systems Incorporated |
| .SXT | FMJ-Software | Ficheiros de Áudio | Propellerheads Reason 2 NN-XT Sound Data | FMJ-Software Awave Audio | FMJ-Software |
| .SYN | Image-Line | Ficheiros de Áudio | SimSynth Document | FL Studio 12 | Image-Line |
| .SYW | Yamaha Corporation | Ficheiros de Áudio | Yamaha SY99/SY85 Audio File | Awave Studio | FMJ-Software |
| .SYX | Cakewalk, Inc. | Ficheiros de Áudio | MIDI System Exclusive Message | Cakewalk SONAR | Cakewalk, Inc. |
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