AAC
→
AU

Convert AAC to AU Online

Convert AAC to AU online. Start with free daily conversions, no install, no watermarks, and visible job status.

AAC to AU Converter

Upload your AAC file to convert it to AU format

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How to Convert AAC to AU

Follow these simple steps

1

Step 1: Upload Your File

Upload your AAC file by dragging and dropping or clicking to browse

2

Step 2: Select Output Format

AU is automatically selected as the output format

3

Step 3: Start Conversion

Click the Convert button to start the conversion

4

Step 4: Download Result

Download your converted AU file when ready

Convert AAC to AU - Complete Guide

Converting AAC to AU stays in the audio file family but changes the traits that decide size, quality, transparency, editability, or device support. AAC is a compressed audio format used for streaming, mobile playback, and efficient high-quality sound. AU is a audio format. Sun audio. Below is what actually changes in a AAC→AU conversion, what is preserved, and when AU is the better choice than keeping AAC.

What changes when you convert AAC to AU

  • The audio is re-encoded into the AU format. Because re-encoding is not free, start from the highest-quality source you have and keep quality settings high.
  • Expect a larger output file: AU stores AAC content with less aggressive compression.

About the AAC format

AAC (Advanced Audio Coding) is a high-quality audio format that offers better sound quality than MP3 at similar file sizes. It is the default format for iTunes and Apple devices.

  • Full name: Advanced Audio Coding
  • Developer: ISO/IEC
  • Compression: Lossy compression
  • Opens with: Apple devices, most players, browsers

Where AAC is strong: better quality than MP3 at the same bitrate; the standard for Apple and streaming; efficient and widely supported.

Typical AAC uses: streaming audio, Apple Music and iTunes, mobile playback.

About the AU format

AU is a audio format. Sun audio.

  • Compression: mixed
  • Opens with: VLC, Audacity, FFmpeg

Where AU is strong: simple legacy format from Sun/NeXT systems; stores uncompressed PCM or companded mu-law/A-law audio; easy to read and parse.

Typical AU uses: legacy Unix and Java system sounds, older audio archives.

What AU keeps

  • AU adds: simple legacy format from Sun/NeXT systems.

Things to watch out for

  • AU is less universally supported than AAC — make sure your target player or platform accepts AU before converting.
  • One AU limitation to keep in mind: dated format rarely used today.

When to convert AAC to AU

  • Convert AAC to AU for legacy Unix and Java system sounds.
  • Convert AAC to AU for older audio archives.
  • Pick AU when you need stores uncompressed PCM or companded mu-law/A-law audio.

AAC vs AU — format comparison

A quick side-by-side of the structural differences between AAC and AU, so you can confirm this is the right conversion for your file:

AttributeAACAU
TypeAudio fileAudio file
CompressionLossyFlexible (lossy or lossless)
Web-friendlyYesNo
Typical file sizeSmallMedium
Best forstreaming audiolegacy Unix and Java system sounds

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Need the opposite conversion?

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Other AAC Conversions

More formats you can convert AAC to

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Convert to AU

Other formats you can convert to AU

Convert MP3 to AUConvert WAV to AUConvert OGG to AUConvert FLAC to AUConvert M4A to AUConvert WMA to AUConvert AIFF to AUConvert OPUS to AUConvert AC3 to AUConvert AMR to AUConvert CAF to AUConvert MKA to AUConvert WV to AUConvert SPX to AUConvert OGA to AUConvert DTS to AUConvert MP2 to AU
View all AU conversions →

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AAC to AU FAQ

Converting AAC to AU preserves the content faithfully; output also depends on the source file and any settings you choose.
Upload your AAC file, confirm AU as the output format, and click Convert. Job status is shown while the file is processed, then you can download the AU result.
Yes. You can start with free daily conversions, with no signup required for your first jobs and no watermarks on the output. Accounts and paid plans are available for higher-volume work.
No. The AAC to AU conversion runs in your browser on any device — Windows, Mac, Linux, iOS, or Android — with uploads and downloads over HTTPS.
AAC is an audio format designed to be the successor to MP3. It offers better quality at lower bitrates.
Yes, AAC typically sounds better than MP3 at the same bitrate, especially at lower bitrates (128 kbps).
Most modern devices support AAC, including all Apple devices, Android phones, and newer media players.
Processing time depends on file size, format, and queue load. The page shows job status while conversion runs.
Yes. You can add multiple AAC files to a batch and process them together within the current file-size and credit limits.

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