SOU to AU Converter

Move your SOU audio to AU format in seconds online

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Format Upgrade

SOU recordings become far more usable as AU. The conversion unlocks simple well-documented structure that SOU cannot provide.

Secure Processing

All uploaded files are handled securely — SOU inputs are removed after processing, and AU outputs expire within 24 hours.

Fast Results

Speed matters. Our converter transforms SOU to AU in moments, so you get your audio in the right format without waiting.

How to convert SOU to AU

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose au or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your au file right afterwards

About formats

SOU is a raw audio format designation that functions as an alias for unsigned 8-bit PCM data (u8) in the SoX audio processing framework. Files with the .sou extension contain headerless, uncompressed audio samples stored as unsigned 8-bit integers — each byte represents a single amplitude value from 0 to 255, with 128 as the silence midpoint. Because there is no header, playback parameters such as sample rate and channel count must be specified externally. The default assumption is typically mono at 8000 Hz, though the data can represent any rate the recording hardware supported. The u8 encoding that SOU aliases is one of the simplest possible digital audio representations, predating structured audio containers like WAV and AIFF. Raw unsigned PCM was commonly produced by early sound cards and digitizers in the late 1980s and early 1990s, when storage constraints and limited processing power made headerless formats a practical choice. One advantage is absolute simplicity: SOU files can be read by any program capable of basic file I/O, with no parsing of container structures or metadata decoding required — useful for embedded systems, hardware diagnostics, and educational contexts where audio fundamentals are being explored. The format's minimal overhead also means that conversion to any modern container is lossless and instantaneous, since the raw PCM samples can be wrapped in a WAV or AIFF header without any transcoding.
Developer: SoX Contributors
Initial release: 1991
AU is an audio file format introduced by Sun Microsystems for its Unix workstations and the NeXT platform. It features a minimal 24-byte header specifying data offset, size, encoding type, sample rate, and channel count, followed by the audio payload. AU supports numerous encodings, including uncompressed linear PCM at various bit depths, mu-law and A-law companding (logarithmic compression used in telephone systems), and several ADPCM variants. This versatility made AU a workhorse across early Unix environments, web audio (Java applets defaulted to AU), and telephony applications. One advantage is simplicity: the compact header and straightforward structure make it trivial to parse, generate, and stream programmatically. The built-in mu-law option provides another benefit, delivering reasonable voice quality at just 8 KB per second — half the rate of 16-bit uncompressed audio — invaluable when storage and bandwidth were scarce. Although modern formats have largely supplanted AU in consumer applications, it retains a foothold in scientific computing and audio processing pipelines where minimal overhead and reliable cross-platform behavior are valued.
Developer: Sun Microsystems
Initial release: 1992

Frequently Asked Questions

Why should I switch from SOU to AU?

SOU suffers from bare PCM data requiring manual configuration to play back. AU offers cross-platform Unix support.

Which software opens AU recordings?

You can open AU with VLC, Audacity, SoX, and Unix/Linux media players.

Is there quality loss from SOU to AU?

No quality is lost. AU stores audio without additional compression, so your SOU recording carries over at full original fidelity.

Is SOU to AU conversion available on all platforms?

It works on any platform — desktop or mobile. Just open your browser, upload the SOU recording, and convert to AU.

Is my SOU audio kept private during conversion?

Your uploaded SOU recordings are deleted immediately after conversion. The resulting AU outputs are removed within 24 hours.

Do I need to install anything for SOU to AU?

No installation required. The converter runs entirely in your web browser — just upload, convert, and download.