What is the SDX file format?
An .sdx file belongs to the audio file category and is also known as the Sample Dump Exchange file or "Sample sound file." Originally created by FMJ-Software as part of their Awave Studio tooling, the format is closely tied to the MIDI Sample Dump Standard - a protocol for transferring digital audio samples between hardware samplers and computers.
Each .sdx file stores a single mono instrument sample: raw PCM-style audio data together with attributes such as bit depth, loop points, root key, and sample-rate metadata. These parameters were essential for samplers and wavetable editors of the 1990s sampler era. Unlike general-purpose formats such as .SF2 or .WAV, the .sdx format uses a proprietary binary container with no documented fixed file signature, so files are best identified by their extension rather than their header bytes.
On Windows, .sdx files are automatically associated with Awave Studio when it is installed. Awave Studio remains the primary application capable of opening and converting .sdx files. For modern workflows, samples are typically exported to interoperable formats like .wav or .AIFF.
Security & safety
RISK: LOWAn audio SDX sample is passive data with no executable code, so risk is low. The main pitfall is misidentification: an .sdx that is actually a PocketBook dictionary, SmartDraw library or Photoshop scratch file will not open in an audio tool. Download Awave Studio only from fmjsoft.com.
Format details
in a nutshell- PocketBook dictionary (SDX) - Dictionary/index file used by PocketBook e-readers (paired with .dic data).
- SmartDraw extension/library file - Add-on or symbol library used by the SmartDraw diagramming application.
- Photoshop scratch / temp file - Temporary scratch-disk file some Adobe Photoshop setups have written with an .sdx name.
Programs that open SDX files
Windows1 app
Awave Studio
Paid File → Open the .sdx; play/edit the sample, then File → Save As to export WAV/AIFF. Technical details
deep spec| Format type | Binary proprietary sample container |
| Audio encoding | Uncompressed PCM-style sample data (no lossy compression applied) |
| Channel layout | Mono only |
| Bit depth | Variable; sampler-dependent, typically 8 to 16 bits per sample |
| Sample rate | Sampler-dependent; common sampler-era rates such as 22,050 Hz and 44,100 Hz |
| Stored metadata | Loop start and end points, root key (MIDI note number), bit depth, and sample rate |
| File size range | Typically a few KB to a few MB per individual sample |
| File signature | No fixed documented magic bytes; identified by extension and application association |
| MIME type | audio/x-sdx (application/octet-stream used as generic fallback) |
| Associated OS | Windows (auto-associated with Awave Studio upon installation) |
| Primary application | Awave Studio by FMJ-Software |
| Related standard | MIDI Sample Dump Standard (MDS), the hardware protocol for exchanging samples between samplers |
| Sample content | Single instrument sample per file - one patch or articulation stored per .sdx file |
| Encryption | No encryption; files are stored as plain binary data |
| Superseded by | Modern sampler formats such as SF2, SFZ, and plain WAV or AIFF files |
| Released | 1990s (associated with MIDI Sample Dump Standard tooling) |
| Specification | www.fmjsoft.com |
SDX conversions
Community Q&A
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