Trim AU

How to Trim AU Audio

1. Upload your AU file — Click "+ Add Files" or drag and drop your AU (Sun/NeXT) audio file.
2. Set trim points — Under "Trim," enter a start time and duration.
3. Adjust compression (optional) — Under "File Compression," select "Quality Preset" (Highest to Lowest) or "Constant Bitrate" for fixed bitrate output.
4. Set audio channel (optional) — Under "Audio Channel," choose mono or stereo.
5. Set sample rate (optional) — Under "Audio Sample Rate," select the output sample rate.
6. Trim and download — Click "Trim" and download your trimmed AU file.

Why Trim AU Files?

AU is Sun Microsystems' audio format, originally developed for Unix/Solaris systems and NeXT computers. AU files are found in legacy Unix audio archives, scientific data recordings, telephony systems (mu-law encoding), and older Java applications that used javax.sound. Trimming lets you extract specific segments from these recordings without converting to another format.

AU files typically use mu-law or linear PCM encoding and are uncompressed or minimally compressed, making them relatively large for their duration.

AU Format Details

Property	Value
Developer	Sun Microsystems
Encoding	mu-law, A-law, linear PCM
Sample rates	8000 Hz (telephony) to 48000 Hz
Channels	Mono or stereo
Primary use	Unix/Solaris, telephony, Java audio
File size	Large (uncompressed PCM)

Frequently Asked Questions

What is AU format?

AU is Sun Microsystems' audio format for Unix systems. It uses mu-law encoding (common in telephony) or linear PCM. Found in legacy Unix archives, scientific recordings, and older Java applications.

What compression setting should I use?

"Quality Preset: High" preserves good quality. For telephony-grade audio (8000 Hz mu-law), "Constant Bitrate" at 64 kbps is sufficient.

Should I use mono or stereo?

Most AU files are mono (telephony, voice). Keep mono unless the source is stereo music or multi-channel scientific data.

Can I change the sample rate?

Yes. Under "Audio Sample Rate," select the output rate. 8000 Hz is standard for telephony AU files. 44100 Hz for music-quality output.

Should I trim as AU or convert to WAV?

For modern use, AU to WAV or AU to MP3 is recommended. Keep AU only for legacy Unix systems or telephony workflows.