About SND Files
NeXT Sound
SND (NeXT Sound) is an audio file format originating from NeXT computers and later adopted by Sun Microsystems as the AU format. It stores audio with a simple header and supports various encodings from 8-bit mu-law to 32-bit floating point.
Family
Audio Files
Extension
.snd
MIME Type
audio/basic
Can Use As
HOW SND
CAME TO BE.
The .snd extension covers a handful of related audio formats from the late 1980s. On NeXT computers (Steve Jobs’ post-Apple workstation), .snd was the native sound file format — essentially the same as Sun’s AU format (a 24-byte header followed by audio samples in µ-law or PCM). On classic Macintosh, a different .snd existed inside resource forks carrying System 7 alert sounds. These formats are commonly confused because they share the same extension.
Both NeXT .snd and Mac .snd are essentially extinct. NeXTSTEP evolved into macOS (where .snd gave way to AIFF), and Mac System 7 died with OS X. Files with .snd extension today usually come from audio-preservation archives or retrocomputing projects. FFmpeg and SoX read the NeXT/Sun .snd variant; Mac .snd requires specialized old-Mac tooling.
CURIOSITIES &
TRIVIA.
NeXT .snd files are byte-identical to Sun AU files — rename .snd to .au and any audio player decodes them.
Classic Macintosh .snd lived inside HFS resource forks — a feature modern filesystems no longer support.
NeXT System sounds (the iconic Steve Jobs-era alerts) were .snd files packaged in NeXT app bundles.
Jobs used .snd files as the first "system alert" sound design in NeXT demos.
Modern macOS Alert Sounds trace to a design ethos that started with NeXT .snd.
STRENGTHS &
LIMITATIONS.
Strengths
- Historical NeXT archive format.
- Compatible with Sun AU.
- Simple header structure.
Limitations
- Legacy — no new content.
- Ambiguous — NeXT .snd and Mac .snd are different formats.
- Requires specialized tooling for Mac resource-fork variant.
Typical Sizes & Weights
NeXT System alert
5-50 KB
Technical Specifications
- MIME type
- audio/basic
- Extension
- .snd
- NeXT variant
- Identical to Sun AU
- Mac variant
- HFS resource fork format
CONVERT FROM
SND
Common Use Cases
Unix system sounds, NeXT/Sun legacy audio, basic audio interchange
Related Formats
Popular comparisons
SND vs MP3
Differences, file size, and when to choose each format.
SND vs WAV
Differences, file size, and when to choose each format.
SND vs FLAC
Differences, file size, and when to choose each format.
SND vs AAC
Differences, file size, and when to choose each format.
SND vs M4A
Differences, file size, and when to choose each format.
SND vs OGG
Differences, file size, and when to choose each format.
Popular SND conversions
The most-requested destinations when starting from SND.
Frequently Asked Questions about SND
Frequently Asked Questions
SND (NeXT Sound) is an audio file format used to store sound recordings — music, voice, podcasts, sound effects. The format defines how the audio samples are compressed (or stored raw), what bitrates are supported, and how metadata such as title, artist, album, and cover art is embedded. It is part of the audio files family.
VLC, foobar2000, and the default media players on Windows and macOS handle SND natively. On mobile, iOS Music and Android media apps vary in their support — popular formats work everywhere; niche ones may need a dedicated app. If playback fails on a device, converting to MP3 or AAC usually solves it.
Upload the SND to KaijuConverter and pick MP3, WAV, FLAC, AAC, OGG, or any other target. Our FFmpeg pipeline decodes the audio and re-encodes to the target format at sensible default bitrates (VBR ~190 kbps for music, 96 kbps for speech). Metadata and cover art travel with the audio where both formats support them.
SND can be lossy or lossless depending on the specific variant. Lossy variants (smaller files) discard some audio detail during compression in ways tuned to be inaudible; lossless variants preserve every sample exactly but produce larger files. For distribution, lossy at high bitrate is standard; for archival, lossless wins.