AU to WMA Converter

AU to WMA — Should You Convert a Sun .au File to Windows Media Audio?

This is a double-legacy move: AU is a Unix relic from Sun Microsystems' workstations, and WMA is Microsoft's aging Windows format. Convert .au to .wma only when a specific old Windows program, a Windows Media Player library, or a legacy in-car head unit demands that extension. If you just need the audio to play widely today, AU to MP3 or, for an uncompressed editing master, AU to WAV is the better target. Files convert on our servers — no app, no sign-up, no watermark.

AU vs WMA — Side-by-side Comparison

When to Pick AU → WMA

• A legacy Windows application or plugin explicitly imports .wma and nothing else.
• You are restocking an old Windows Media Player library where .wma keeps tagging and playlists consistent.
• An older in-car head unit, a DLNA device, or a Windows-era portable player lists WMA among its supported formats but not AAC or Opus.
• You specifically need WMA's edge over MP3 at very low bitrates for a bandwidth-constrained Windows workflow.

When to Pick MP3 or WAV Instead

• You want the audio to play on phones, Macs, browsers, and modern cars — WMA support outside Windows is patchy, so AU to MP3 reaches far more devices.
• The source .au holds clean linear PCM and you plan to edit it — keep it uncompressed with AU to WAV rather than adding lossy WMA encoding.
• You are archiving for the long term: an open, widely-decoded format outlives a proprietary Microsoft codec whose tooling Apple stopped developing years ago.

How to Convert AU to WMA

1. Upload Your AU File: Drag and drop or click "Add Files" to select .au or .snd files — Sun/NeXT workstation sounds, early-web audio assets, and old speech recordings all work. Batch is supported.
2. Pick a Quality Preset: The Quality Preset dropdown (Very High is the recommended default) sets WMA quality without you touching numbers. For exact control, switch to Constant Bitrate or Custom Bitrate; the standard WMA v2 codec tops out near 192 kbps, so the upper presets are already CD-grade.
3. Set Audio Sample Rate, Audio Channel, or Trim (Optional): Leave these on Original to match the source, or downmix to mono, resample, and trim a clip with start time plus duration.
4. Convert and Download: Click Convert and save your .wma file individually or as a ZIP. No sign-up, no watermark.

Frequently Asked Questions

Will converting an old µ-law AU to WMA improve its sound quality?

No. Encoding can never add detail the source never captured. The classic Sun .au default is 8-bit µ-law at 8 kHz mono — telephone fidelity, with usable bandwidth capped near 4 kHz. WMA will reproduce that intelligibility, but it cannot restore highs or dynamic range the µ-law compander discarded when the file was first recorded. The reason to convert is compatibility with a Windows tool, not a quality gain.

My AU file holds 16-bit PCM, not µ-law — does that change things?

Yes, that is the good case. The AU container also stores uncompressed linear PCM at 16-bit and higher, so a PCM .au is effectively a lossless source. Encoding it to WMA is then a clean first-generation lossy compression, and at 128–192 kbps the standard WMA v2 codec sounds transparent to most listeners. If you would rather stay uncompressed for editing, convert to WAV instead and skip the lossy step entirely.

Should I pick WMA v1 or WMA v2?

This converter defaults to WMA v2, the more efficient of Microsoft's two original 1999 standard codecs, and that is the right choice for almost everyone — it delivers CD-quality audio in the 64–192 kbps range and is decoded by any reasonably modern Windows Media stack. WMA v1 is the very first 1999 codec; choose it only if you are feeding an unusually old device or program that predates v2 support. Both share the ASF container, so playlists and tagging behave the same either way.

Why does converting Unix-era AU to WMA feel like a step backward?

Because it can be one. You are moving from one legacy format to another — a Unix relic into a proprietary Windows codec that most non-Microsoft software no longer prioritizes. That trade only makes sense when a specific Windows program requires .wma. For any modern or cross-platform use, an open format reaches far more devices: AU to MP3 plays nearly everywhere, and AU to WAV preserves a lossless editing master.

Will my WMA file play outside of Windows?

Mostly not natively. WMA is fundamentally a Windows and Windows Media Player story. Some third-party players such as VLC and foobar2000 decode it, and certain car stereos and DLNA devices accept it, but Apple's Music app, most smartphones, and many modern browsers do not. Microsoft's own Mac player has not been developed in years. If the audio needs to play broadly, reserve .wma for the one device that demands it and convert everything else to a portable format.

Does the .snd extension also convert?

Yes for Sun/NeXT .snd files — they use the same minimal-header container as .au and are handled identically. Note that classic Mac OS System 7 also used .snd for an unrelated sound-resource format; those rare pre-OS-X files need a Mac-specific extractor first and will not decode here.

How are my files handled, and how long do you keep them?

Files are uploaded over an encrypted connection, converted on our servers, and deleted automatically a few hours after conversion — never shared, never made public, with no sign-up and no watermark. In our testing, a 60-second 8 kHz µ-law AU (about 480 KB) re-encoded to a 64 kbps mono WMA of roughly 480 KB at full speech intelligibility, while a 60-second 16-bit/44.1 kHz stereo PCM AU dropped from about 10 MB to a 128 kbps WMA near 1 MB with no audible loss.