SD2 to AU Converter
Processing entirely on your device — large files may take a moment.
SD2 (Sound Designer II) is Digidesign's classic Pro Tools container — still the default export of many legacy studio sessions and Mac-era sample libraries. 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 SD2 compares to AU
| SD2 | AU | |
|---|---|---|
| Compatibility | ffmpeg, archive tools | Legacy Unix tools |
| Best for | Rescuing legacy audio | Old system sounds and recordings |
How to convert SD2 to AU
- 1
Select your files
Drag & drop your SD2 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 SD2 format
HCOM is the Sound Tools compressor format from the late 1980s Mac — FIR-decimated delta-modulation samples that almost nothing modern reads.
ffmpeg decodes it natively inside your browser — the audio track is re-encoded to your chosen format with nothing ever uploaded.
+ Strengths
- ✓Decoded natively by ffmpeg
- ✓Runs entirely in your browser
- ✓Free, private, no watermarks
! Limitations
- −Legacy niche format
- −Modern tools rarely open it
- −Keep the original for archival round-trips
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 SD2 to AU?
Think of it as moving your file to the container that fits the job. Legacy niche format 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 SD2 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 SD2 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.
Will converting SD2 to AU reduce audio quality?
If AU is lossless, the output contains everything the SD2 file contains — no further loss is added. If AU 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.
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.