GSM to VOC Converter
Processing entirely on your device — large files may take a moment.
GSM 06.10 Speech and Creative Sound Blaster VOC exist for different jobs: GSM 06.10 is the 1990s mobile-telephony speech codec — 13 kbit/s audio that VoIP systems and old answering machines still emit. Convert VOC retro-game audio to WAV or MP3.
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 GSM compares to VOC
| GSM | VOC | |
|---|---|---|
| Structure | Raw GSM frames (33 bytes/20ms) | Creative Voice file blocks (0x08 header) |
| Types / schema | Lossy speech codec (RPE-LTP) | 8-bit PCM / ADPCM variants |
| Compatibility | Asterisk, SoX, ffmpeg | ffmpeg, Sound Blaster era tools |
| Best for | Telephony recordings | Retro-game audio rescue |
How to convert GSM to VOC
- 1
Select your files
Drag & drop your GSM 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 VOC". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted VOC file individually, or grab everything at once as a ZIP archive.
About the GSM format
GSM 06.10 is the speech codec of the original GSM mobile network — 13 kbit/s RPE-LTP that made digital cellphone calls possible in 1991 and still lives inside VoIP systems, old answering machines and Asterisk PBX recordings.
It is lossy speech, not music: converting GSM to WAV or MP3 preserves intelligibility perfectly while finally letting desktop players open the file without special codecs.
+ Strengths
- ✓Tiny bitrate for speech intelligibility
- ✓Ubiquitous in telephony systems
- ✓Decodes natively via ffmpeg
! Limitations
- −Speech-only quality — music falls apart
- −13 kbit/s artifacts are audible
- −8000 Hz sample rate only
About the VOC format
VOC is the Creative Sound Blaster format — if a DOS game made a sound between 1989 and 1994, it was probably a VOC: 8-bit samples at exotic sample rates, with loop points, silence blocks and hardware-specific appendices that made each card sing differently.
ffmpeg decodes the standard sample blocks and converts VOC to WAV or MP3 — the cheapest time machine for retro-game audio.
+ Strengths
- ✓The DOS gaming era's audio format
- ✓Unique features: loops, silence, transfer blocks
- ✓Simple to decode
! Limitations
- −8-bit/11kHz era fidelity
- −Creative hardware extensions lost on convert
- −Rarely produced after 1995
Why convert GSM to VOC?
Converting makes sense where the strengths of VOC meet what GSM cannot give you. The DOS gaming era's audio format Meanwhile Speech-only quality — music falls apart One pass through the converter above puts your file on the right side of that trade-off.
Frequently asked questions
Is this GSM to VOC 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 GSM to VOC?
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.
Will converting GSM to VOC reduce audio quality?
If VOC is lossless, the output contains everything the GSM file contains — no further loss is added. If VOC is lossy, one recompression pass is unavoidable; the quality slider controls how much. Loss that already happened in the source file can never be undone by converting.
Can I convert a whole folder of GSM 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.