SD2 to FLAC Converter
Processing entirely on your device — large files may take a moment.
Sound Designer II and FLAC Lossless Audio exist for different jobs: SD2 (Sound Designer II) is Digidesign's classic Pro Tools container — still the default export of many legacy studio sessions and Mac-era sample libraries. Convert to FLAC when you want a permanent, lossless archive of your music.
Because the whole conversion happens on your device, it is instant, unlimited and genuinely private — no accounts, no watermarks, no files on anyone's server. Multiple files are converted in one go.
How SD2 compares to FLAC
| SD2 | FLAC | |
|---|---|---|
| Compatibility | ffmpeg, archive tools | Players, Android, hi-res rigs |
| Best for | Rescuing legacy audio | Music collections and archival |
How to convert SD2 to FLAC
- 1
Select your files
Drag & drop your SD2 files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to FLAC". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted FLAC file individually, or grab everything at once as a ZIP archive.
About the SD2 format
HCOM is the Sound Tools compressor format from the late 1980s Mac — FIR-decimated delta-modulation samples that almost nothing modern reads.
ffmpeg decodes it natively inside your browser — the audio track is re-encoded to your chosen format with nothing ever uploaded.
+ Strengths
- ✓Decoded natively by ffmpeg
- ✓Runs entirely in your browser
- ✓Free, private, no watermarks
! Limitations
- −Legacy niche format
- −Modern tools rarely open it
- −Keep the original for archival round-trips
About the FLAC format
FLAC (Free Lossless Audio Codec, Xiph, 2001) compresses audio to roughly 50–60% of its PCM size and restores every bit on playback — a ZIP for music that also carries proper tags, hi-res support up to 32-bit/655 kHz on paper (24-bit/192 kHz in practice) and full open-source pedigree. It is the archive format of digital music collections.
Support followed maturity: every serious player, modern Android (system-level), most cars and streaming purists' devices handle FLAC natively. Apple resisted for years but iOS 11+ plays it, with the caveat that iTunes/Apple Music syncing still prefers ALAC. The price of losslessness is size — about five times MP3 at comparable quality.
+ Strengths
- ✓Bit-perfect lossless with real compression
- ✓Hi-res capable (24-bit/192 kHz)
- ✓Open, unpatented, tag-native
! Limitations
- −~5× the size of lossy formats
- −Apple syncing prefers ALAC
- −Overkill for casual listening
Why convert SD2 to FLAC?
Converting makes sense where the strengths of FLAC meet what SD2 cannot give you. Bit-perfect lossless with real compression Meanwhile Legacy niche format One pass through the converter above puts your file on the right side of that trade-off.
Frequently asked questions
Is this SD2 to FLAC converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
Is there a file size limit for SD2 to FLAC?
The only limit is your device's memory, since nothing is uploaded. Files up to a few hundred megabytes work fine on a modern desktop browser; very large files simply take a little longer.
Are tags like title and artist preserved?
Tag handling varies between target formats and this conversion focuses on the audio itself. For archival copies where tags matter, keep the original file; the converted copy is for playback and sharing.
Can I convert a whole folder of SD2 files?
You can select many files at once and they are processed in a single batch. Output files land in one ZIP download when there is more than one result.