SPX to W64 Converter
Processing entirely on your device — large files may take a moment.
SPX is Speex voice audio in an Ogg container — the codec of old VoIP recorders and Asterisk phone systems. Convert W64 recordings to WAV or FLAC for standard editors.
Because the whole conversion happens on your device, it is instant, unlimited and genuinely private — no accounts, no watermarks, no files on anyone's server. Multiple files are converted in one go.
How SPX compares to W64
| SPX | W64 | |
|---|---|---|
| Compatibility | Legacy VoIP stacks | Sony Vegas, ffmpeg, Sound Forge |
| Best for | Call recordings, phone systems | Long-duration uncompressed sessions |
How to convert SPX to W64
- 1
Select your files
Drag & drop your SPX files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to W64". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted W64 file individually, or grab everything at once as a ZIP archive.
About the SPX format
SPX is Speex speech audio in an Ogg container — the open voice codec of the 2000s VoIP wave, tuned for telephone-band speech at absurdly low bitrates. Asterisk PBX call recordings and old conferencing archives are where you meet it.
Speex was formally retired in favor of Opus, and players have followed. Converting SPX to MP3 (or Opus for the adventurous) rescues call archives before they become unplayable.
+ Strengths
- ✓Extremely compact for speech
- ✓Open-source lineage
! Limitations
- −Speech-only: music is unusable
- −Format officially retired
About the W64 format
W64 is Sony's Wave64 — what happens when WAV's 32-bit size fields run out of road. A RIFF variant with 64-bit offsets, it shrugs off the 4 GB ceiling that makes plain WAV choke, which is why long field-recording sessions and Sony Vegas projects land in W64.
Inside, it is the same uncompressed PCM as WAV — ffmpeg hands W64 to WAV, FLAC or MP3 without touching a single sample, so conversion is purely about container compatibility.
+ Strengths
- ✓No 4 GB size ceiling — hours-long recordings
- ✓Bit-exact PCM, same as WAV inside
- ✓Standard in Sony Vegas workflows
! Limitations
- −Almost nothing outside Sony tools opens it
- −Uncompressed — very large files
- −Legacy niche — new tools prefer RF64
Why convert SPX to W64?
There is a concrete reason this conversion exists: Speech-only: music is unusable W64 sidesteps that — No 4 GB size ceiling — hours-long recordings If that is your situation, the tool above settles it in seconds, entirely on your device.
Frequently asked questions
Is this SPX to W64 converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
Is there a file size limit for SPX to W64?
The only limit is your device's memory, since nothing is uploaded. Files up to a few hundred megabytes work fine on a modern desktop browser; very large files simply take a little longer.
Will converting SPX to W64 reduce audio quality?
If W64 is lossless, the output contains everything the SPX file contains — no further loss is added. If W64 is lossy, one recompression pass is unavoidable; the quality slider controls how much. Loss that already happened in the source file can never be undone by converting.
Can I convert a whole folder of SPX files?
You can select many files at once and they are processed in a single batch. Output files land in one ZIP download when there is more than one result.