SPX vs WV
A detailed comparison of Speex Audio and WavPack Audio — file size, quality, compatibility, and which format to choose for your workflow.
Speex 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 filesWavPack Audio
Audio FilesWavPack is an open-source audio codec that offers lossless, lossy, and hybrid compression modes. Its unique hybrid mode creates a lossy file plus a correction file that together reconstruct the original, enabling flexible storage strategies.
About WV filesStrengths Comparison
SPX Strengths
- Patent-free voice codec.
- Three sample-rate modes for voice.
- Low CPU decode.
WV Strengths
- Hybrid lossy/lossless mode.
- Supports DSD, 32-bit float, multichannel.
- Competitive compression vs FLAC.
- Active maintenance since 1998.
Limitations
SPX Limitations
- Deprecated in favor of Opus.
- No music support.
- Rarely used in new projects.
WV Limitations
- Small ecosystem.
- Hybrid mode complexity.
- Hardware support limited vs FLAC.
Technical Specifications
| Specification | SPX | WV |
|---|---|---|
| MIME type | audio/speex | audio/x-wavpack |
| Extension | .spx | .wv (main), .wvc (correction) |
| Container | Ogg | — |
| Modes | Narrowband/Wideband/Ultra-wideband | Lossless, Hybrid lossy+correction, 32-bit float |
| Successor | Opus | — |
| License | — | BSD-style |
Typical File Sizes
SPX
- 1 min voice (wideband 24 kbps) ~180 KB
WV
- 3-min song (CD lossless) 18-24 MB
- 3-min hi-res 24/96 60-90 MB
Ready to convert?
Convert between SPX and WV online, free, and without installing anything. Encrypted upload, automatic deletion after 60 minutes.
Frequently Asked Questions
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.
SPX (Speex Audio) is an audio formatoo de arquivo used to store sound recordings — music, voice, podcasts, sound effects. The formato defines how the audio samples are comprimido (or stored raw), what bitrates are suportado, e how metadata como title, artist, album, e cover art is embedded. It is part of the audio arquivos family.
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.
VLC, foobar2000, e the default media players no Windows e macOS handle SPX natively. On mobile, iOS Music e Android media apps vary in their support — popular formatoos funcionar everywhere; niche ones may need a dedicated app. If playback fails em um device, convertendo to MP3 ou AAC Geralmente solves it.
Upload the SPX 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.
SPX 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.