SPX vs AU — Comparison & Free Converter
Fast, instant SPEEX to AU conversion. No signup required. Just drop your .spx file and get .au in seconds.
Batch Settings
About SPEEX to AU Conversion
SPX or AU — which format should you use? The answer depends on your needs. Here's a quick breakdown.
SPX is a widely used file format. It has common platform support. AU is a widely used file format. It has common platform support.
So when should you convert SPX to AU? This conversion is ideal when you When you need a AU file. This conversion helps you convert between formats quickly.
Converting SPX to AU maintains high quality with CocoConvert's optimised encoder settings.
If you've decided AU is the right choice, CocoConvert makes the conversion effortless. Upload your .spx file, pick AU, and click Convert — done in seconds. The converter runs on secure servers in Germany, powered by FFmpeg, Sharp, and qpdf. Files are encrypted via TLS and erased within 24 hours.
Free tier: 5 files/hour, 250 MB each. Pro: 100 files/hour, 5 GB each. Works in every modern browser on desktop and mobile.
How to Convert SPEEX to AU
- 1
Choose your SPX file
Upload your .spx file using drag-and-drop or the file browser. Batch mode lets you add multiple files.
- 2
Set format to AU
Select .au from the output options. The converter applies optimal quality settings automatically.
- 3
Run the conversion
Click Convert. Server-side processing means your device stays fast — even for large audio files.
- 4
Get your AU file
Download your converted file instantly. Batch downloads are available as a zip archive.
What Happens When You Convert SPEEX to AU
Your SPX file is decoded and re-encoded as AU.
Your SPX file is uploaded and validated
The file is decoded (parsed into its raw data)
The data is re-encoded in AU format
The converted file is ready for download
Format Comparison
Speex
.spx file
| Extension | .spx |
| MIME Type | audio/ogg |
| Category | Audio |
AU
.au file
| Extension | .au |
| MIME Type | audio/basic |
| Category | Audio |
Should You Convert SPEEX to AU?
When to Convert
- ✓When you need a AU file
Frequently Asked Questions
Should I use SPX or AU?
It depends on your goal. SPX preserves full quality. AU preserves full quality. Choose based on whether file size or quality matters more for your use case.
Is AU higher quality than SPX?
Not necessarily. Converting SPX to AU maintains high quality with CocoConvert's optimised encoder settings. Quality depends on the compression type and settings, not just the format name.
Can I convert SPX to AU on Mac and Windows?
Yes. CocoConvert is a web-based tool that works in all modern browsers — Chrome, Safari, Firefox, Edge — on any operating system including macOS, Windows, Linux, iOS, and Android.
Is CocoConvert free for SPX to AU?
Yes. Free users get 5 conversions per hour (250 MB each). Pro subscribers unlock 100 files per hour, 5 GB per file, and priority processing.
What tools does CocoConvert use for SPX to AU?
CocoConvert uses FFmpeg for audio/video, Sharp for images, and qpdf for documents — the same open-source libraries used by Netflix, YouTube, and major enterprise platforms.
Versions are pinned in our worker Dockerfile and re-built via CI on every change.