CONVERT
WAV → AU
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Fast, secure WAV to AU conversion. No registration required.
Opening note — WAV is Microsoft's uncompressed PCM container — the studio master format on Windows. The AU you want is two clicks away. Converting WAV to AU changes the audio container without re-recording anything. Whether you are moving from a studio master to a distribution format or just making a file playable on an old car stereo, KaijuConverter re-encodes the audio with FFmpeg at your chosen bitrate and preserves sample rate, channels and ID3 tags. The source WAV file stays untouched. Background. WAV is Microsoft's uncompressed PCM container — the studio master format on Windows. Destination side, AU is the Sun/NeXT audio format, a historical PCM container still found in older pipelines.
WAV Audio
Source formatWAV is an uncompressed audio format that preserves full audio fidelity. Files are large but provide lossless, CD-quality sound. It is the standard working format in audio production and editing.
Sun AU Audio
Target formatAU is a simple audio format from Sun Microsystems, commonly used on Unix systems.
Why convert WAV to AU
WAV Audio is great in its own niche, but Sun AU Audio is either more universally playable or better suited to the device you are targeting. Converting lets you ship the audio without asking listeners to install a codec. The loss in quality between the two is negligible at sensible bitrates.
HOW TO CONVERT
WAV → AU
Upload the WAV
Drop or select your WAV file. The upload is encrypted and the file is queued for conversion.
Transcode via FFmpeg
FFmpeg decodes the WAV stream to PCM internally, then re-encodes as AU at the bitrate you select.
Download the AU
The AU is delivered as a direct download; metadata and cover art transfer automatically where possible.
Common Use Cases
Share across platforms
Send AU files to anyone without worrying about whether they have the right software for WAV.
Embed in documents
Drop AU output into Word, Google Docs, PowerPoint, Notion or a website without conversion warnings.
Optimize size
AU often produces smaller files than WAV for web, email and storage.
Archive & future-proof
Store in a widely-supported format that will still open on future operating systems without legacy plugins.
WAV vs AU — Strengths and limitations
What each format does best, and where it falls short.
WAV Strengths
- Bit-perfect, uncompressed audio — the professional studio standard.
- Universally supported for playback, editing, and analysis.
- No re-encoding penalty — edit and save repeatedly with zero quality loss.
- Simple internal structure — easy to parse programmatically.
- Supports up to 32-bit float and 384 kHz sample rates.
Limitations
- Enormous file sizes — 10 MB per minute for CD-quality stereo.
- 4 GB size limit for standard WAV (RF64/W64 variants extend it but break compatibility).
- No native support for cover art or rich metadata.
AU Strengths
- Trivially simple format — 24-byte header, then samples.
- µ-law 8-bit variant fits hours of speech in kilobytes.
- Stable since 1988; every major audio library reads it.
- Streaming-friendly: size field is optional.
Limitations
- Aging — obsolete outside legacy and compatibility scenarios.
- No metadata beyond a single annotation string.
- No native multi-channel surround support.
WAV vs AU — Technical specifications
Side-by-side comparison of the technical details.
WAV
- MIME type
- audio/wav
- Container
- RIFF
- Typical codec
- PCM (uncompressed)
- Bit depth
- 8, 16, 24, 32 bit integer or float
- Sample rate
- Up to 384 kHz
- Max size
- 4 GB (standard WAV), unlimited (RF64 / W64)
AU
- MIME types
- audio/basic, audio/au, audio/x-au
- Extensions
- .au, .snd
- Header
- 24 bytes (magic, offset, size, encoding, rate, channels, info)
- Codecs
- PCM 8/16/24/32-bit, µ-law, A-law, IEEE float
- Byte order
- Big-endian
| Specification | WAV | AU |
|---|---|---|
| MIME type | audio/wav | — |
| Container | RIFF | — |
| Typical codec | PCM (uncompressed) | — |
| Bit depth | 8, 16, 24, 32 bit integer or float | — |
| Sample rate | Up to 384 kHz | — |
| Max size | 4 GB (standard WAV), unlimited (RF64 / W64) | — |
| MIME types | — | audio/basic, audio/au, audio/x-au |
| Extensions | — | .au, .snd |
| Header | — | 24 bytes (magic, offset, size, encoding, rate, channels, info) |
| Codecs | — | PCM 8/16/24/32-bit, µ-law, A-law, IEEE float |
| Byte order | — | Big-endian |
WAV vs AU — Typical file sizes
Approximate file sizes for common scenarios.
WAV
- Song (4 min, CD quality) 40 MB
- Voice memo (1 min, 16-bit 44.1 kHz) 10 MB
- Studio master (1 min, 24-bit 96 kHz) 33 MB
- Field recording (1 hour, 24-bit 48 kHz) 1 GB
AU
- 10-second clip (8-bit µ-law, 8 kHz) 80 KB
- 10-second clip (16-bit PCM, 44.1 kHz stereo) ~1.7 MB
Quality & Compatibility
Lossy-to-lossy transcoding (most cross-format audio jobs) loses a tiny amount of quality on each pass — usually inaudible at our default VBR ~190 kbps for music or 96 kbps for speech. Lossy-to-lossless conversions freeze the existing quality but cannot improve it; lossless-to-lossy is only as good as the target bitrate you choose.
Tips for Best Results
- Pick 128 kbps for podcasts and voice, 192–256 kbps for music, 320 kbps only if the audio will be edited further downstream.
- Keep the WAV master alongside the AU — re-encoding a lossy format twice accumulates audible artefacts.
- For mono voice content, convert to mono AU explicitly to halve file size without any quality loss.
Frequently Asked Questions
Lossy-to-lossy conversions (most combinations) re-compress the audio, which technically introduces some loss. At a 192 kbps or higher target it is inaudible on normal equipment. Lossy-to-lossless conversions freeze the existing quality but cannot improve it; lossless-to-lossy transcodes are only as good as the target bitrate you choose.
For voice content (podcasts, audiobooks, lectures) 128 kbps is indistinguishable from higher bitrates. For music, 192-256 kbps covers most listening; 320 kbps is the ceiling for AU and the right choice for audio you plan to edit further. Above that, prefer a lossless target instead.
Yes. Title, artist, album, year and cover art travel from the WAV container to the AU container automatically where both formats support them. If a tag field has no AU equivalent, it is dropped silently. Use any tag editor (Mp3tag, MusicBrainz Picard) to fine-tune afterwards.
RELATED CONVERSIONS
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Read guideSecure & Private Conversion
Your files are encrypted during transfer, processed in isolated containers, and automatically deleted within 60 minutes. We never read, share, or store your data.