SPX to AU 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. Converting AU to WAV preserves the samples in a format every modern tool reads.
iLoveConverter processes everything locally on your computer, which makes it private and fast: no upload wait, no server storage, no limits. Add as many files as you like — batch conversion is built in.
How SPX compares to AU
| SPX | AU | |
|---|---|---|
| Compression | Lossy Speex (Ogg) | µ-law or PCM |
| Quality | Narrowband/wideband speech | Mono voice-grade (µ-law) |
| Compatibility | Legacy VoIP stacks | Legacy Unix tools |
| Best for | Call recordings, phone systems | Old system sounds and recordings |
How to convert SPX to AU
- 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 AU". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted AU 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 AU format
AU is Sun Microsystems' audio format from the Unix workstation age: a small header followed by µ-law (or PCM) samples. Java's applet era shipped it everywhere, and old Unix sound tooling still emits it.
Modern players increasingly skip it. Converting AU to WAV preserves the samples bit-for-bit while moving the file into universal territory — the standard rescue path for system sounds and old recordings.
+ Strengths
- ✓Simple, lossless sample storage
- ✓Native to old Unix/Java tooling
! Limitations
- −µ-law flavor sounds dated and mono
- −Dropped by modern players
Why convert SPX to AU?
Think of it as moving your file to the container that fits the job. Speech-only: music is unusable AU works differently: Simple, lossless sample storage If any of that sounds like your task, run the conversion — it takes seconds and nothing leaves your device.
Frequently asked questions
Is this SPX to AU 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 AU?
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.
Are tags like title and artist preserved?
Tag handling varies between target formats and this conversion focuses on the audio itself. For archival copies where tags matter, keep the original file; the converted copy is for playback and sharing.
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.