Yes! Convert999 works on any device with a web browser — iPhone, Android, iPad, or desktop. No app installation required. Simply open the converter, upload your AAC file, and download the converted AU file.
Will I lose quality converting AAC to AU?
Convert999 uses high-quality conversion algorithms to minimize quality loss. For lossless formats, the conversion is exact. For lossy formats like images and audio, we use optimized settings that balance quality and file size.
Can I batch convert multiple AAC files to AU?
Yes, Convert999 supports batch conversion. Select or drag & drop multiple AAC files and convert them all to AU format at once. Each file is processed locally in your browser.
What is the difference between AAC and AU?
Advanced Audio Coding (AAC) and Sun Audio (AU) differ in compression, compatibility, and features. AAC is optimized for its native use cases, while AU may offer different advantages. Visit our AAC vs AU comparison page for a detailed breakdown.
Why Convert AAC to AU?
Advantages
✓Sun Audio offers better compatibility with modern applications and workflows
✓Converting is completely free with no file size limits on Convert999
✓Your files never leave your device — 100% private and secure conversion
✓Instant conversion without waiting for server processing
Key Differences
→AAC (Advanced Audio Coding) is optimized for its native use cases
→AU (Sun Audio) may offer different compression or feature set
→Choose based on your target platform, quality needs, and file size requirements