FSB to MP3 Converter
Convert & extract FSB audio files to MP3 online free. Supports FMOD Sound Banks from Hollow Knight, Celeste, Undertale & more. No install required.
What is an FSB Converter?
An FSB converter is a tool that converts FMOD Sound Bank (.fsb) files into playable audio formats like MP3 or WAV. BGM Box uses vgmstream to decode FSB files directly in your browser.
How to Extract Audio from FSB Files?
Simply drag and drop your FSB file into the upload area above. The vgmstream decoding engine extracts the audio, and our MP3 encoder converts it instantly. Your files never leave your computer.
Common Games Using FSB Files
- Hollow Knight — Music and ambient audio in FSB containers
- Celeste — Soundtrack stored as FSB with Vorbis codec
- Undertale — FMOD-based audio system using FSB banks
- Subnautica — Environmental audio and music in FSB format
- Risk of Rain 2 — FMOD sound banks for music and SFX
- Enter the Gungeon — FSB audio containers for game audio
Frequently Asked Questions
FSB (FMOD Sound Bank) is a container format used by the FMOD audio engine, found in thousands of PC and console games including Hollow Knight, Celeste, Undertale, Subnautica, and many more. A single .fsb file can contain multiple audio tracks with different codecs.
Simply drag your .fsb file onto the FSB to MP3 converter page. The vgmstream decoding engine will extract each audio track inside the sound bank and convert it to MP3 automatically. No FMOD Studio or additional tools required.
vgmstream supports FSB versions 3, 4, and 5 with most common codecs (MPEG, Vorbis, PCM, ADPCM, ATRAC3, XMA). Some newer FSB5 variants with custom encryption may not be supported.
The converter currently processes the first audio track in the FSB file. For multi-track FSB files, you may need to use a desktop tool like vgmstream-cli to extract individual tracks individually.