DSF vs SPX
A detailed comparison of DSD Stream File and Speex Audio — file size, quality, compatibility, and which format to choose for your workflow.
DSD Stream File
Audio FilesDSF (DSD Stream File) stores Direct Stream Digital audio data with metadata support. DSD uses single-bit sigma-delta modulation at very high sample rates (2.8 MHz and above), providing extremely high resolution audio favored by audiophiles.
About DSF filesSpeex Audio
Audio FilesSpeex is an open-source audio compression format specifically designed for speech encoding. It uses Code-Excited Linear Prediction (CELP) and supports narrowband, wideband, and ultra-wideband modes for different speech quality requirements.
About SPX filesStrengths Comparison
DSF Strengths
- Preserves SACD audio bit-exact.
- Appeals to audiophiles who prefer DSD-encoded content.
- Sony-supported and documented.
- High-end DACs natively decode DSD without PCM conversion.
SPX Strengths
- Patent-free voice codec.
- Three sample-rate modes for voice.
- Low CPU decode.
Limitations
DSF Limitations
- Enormous file sizes (2-5 GB per album).
- Specialized hardware required for native playback.
- Blind listening tests struggle to distinguish from well-produced 24-bit PCM.
- Niche — overwhelmingly targets the audiophile market.
SPX Limitations
- Deprecated in favor of Opus.
- No music support.
- Rarely used in new projects.
Technical Specifications
| Specification | DSF | SPX |
|---|---|---|
| MIME type | audio/x-dsf | audio/speex |
| Extension | .dsf | .spx |
| Sample rate | 2.8224 MHz (DSD64); 5.6448 (DSD128); 11.2896 (DSD256) | — |
| Bit depth | 1 bit (Sigma-Delta modulation) | — |
| Container | Sony proprietary (similar to DFF) | Ogg |
| Modes | — | Narrowband/Wideband/Ultra-wideband |
| Successor | — | Opus |
Typical File Sizes
DSF
- Single song (DSD64) 150-300 MB
- Full album (DSD64) 2-4 GB
- Single song (DSD256) 600 MB - 1.2 GB
SPX
- 1 min voice (wideband 24 kbps) ~180 KB
Ready to convert?
Convert between DSF and SPX online, free, and without installing anything. Encrypted upload, automatic deletion after 2 hours.
Frequently Asked Questions
DSF (DSD Stream File) is an audio file format used to store sound recordings — music, voice, podcasts, sound effects. The format defines how the audio samples are compressed (or stored raw), what bitrates are supported, and how metadata such as title, artist, album, and cover art is embedded. It is part of the audio files family.
SPX (Speex Audio) is an audio file format used to store sound recordings — music, voice, podcasts, sound effects. The format defines how the audio samples are compressed (or stored raw), what bitrates are supported, and how metadata such as title, artist, album, and cover art is embedded. It is part of the audio files family.
VLC, foobar2000, and the default media players on Windows and macOS handle DSF natively. On mobile, iOS Music and Android media apps vary in their support — popular formats work everywhere; niche ones may need a dedicated app. If playback fails on a device, converting to MP3 or AAC usually solves it.
VLC, foobar2000, and the default media players on Windows and macOS handle SPX natively. On mobile, iOS Music and Android media apps vary in their support — popular formats work everywhere; niche ones may need a dedicated app. If playback fails on a device, converting to MP3 or AAC usually solves it.
Upload the DSF to KaijuConverter and pick MP3, WAV, FLAC, AAC, OGG, or any other target. Our FFmpeg pipeline decodes the audio and re-encodes to the target format at sensible default bitrates (VBR ~190 kbps for music, 96 kbps for speech). Metadata and cover art travel with the audio where both formats support them.
DSF can be lossy or lossless depending on the specific variant. Lossy variants (smaller files) discard some audio detail during compression in ways tuned to be inaudible; lossless variants preserve every sample exactly but produce larger files. For distribution, lossy at high bitrate is standard; for archival, lossless wins.