SPX to PCM Converter
Processing entirely on your device — large files may take a moment.
Speex Voice Audio and Raw PCM Audio (16-bit) exist for different jobs: SPX is Speex voice audio in an Ogg container — the codec of old VoIP recorders and Asterisk phone systems. Convert any audio to raw PCM for DSP pipelines, or wrap a PCM dump into WAV/MP3 to make it playable.
This converter runs entirely in your browser using WebAssembly — your files never leave your device, nothing is uploaded, and there are no watermarks, sign-ups or queues. Drop in several files at once to convert them as a batch.
How SPX compares to PCM
| SPX | PCM | |
|---|---|---|
| Compression | Lossy Speex (Ogg) | None (16-bit LE samples) |
| Best for | Call recordings, phone systems | DSP pipelines, embedded audio |
How to convert SPX to PCM
- 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 PCM". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted PCM 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 PCM format
Raw PCM is audio at its most naked: 16-bit little-endian samples, no header, no metadata, no sample-rate label — just the waveform bytes. It is the lowest common denominator every DSP pipeline, telephony stack and embedded system speaks, which is why exports and lab tools keep asking for it.
Because the file carries no sample-rate information, consumers must agree on the rate out of band (8000 Hz telephony and 48000 Hz video are the common conventions). Wrapping PCM into WAV adds the missing header and makes the bytes playable anywhere.
+Strengths
- ✓Zero overhead — pure sample data
- ✓Universally understood by DSP tools
- ✓Bit-exact lossless representation
!Limitations
- −No header: sample rate must be known out of band
- −Unplayable directly in most apps
Why convert SPX to PCM?
Converting makes sense where the strengths of PCM meet what SPX cannot give you. Zero overhead — pure sample data Meanwhile Speech-only: music is unusable One pass through the converter above puts your file on the right side of that trade-off.
Frequently asked questions
Is this SPX to PCM 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 PCM?
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 PCM reduce audio quality?
If PCM is lossless, the output contains everything the SPX file contains — no further loss is added. If PCM 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.