FLAC to VOX Converter

Encode lossless FLAC as Dialogic ADPCM VOX audio

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Best VOX Quality

Lossless FLAC gives the Dialogic encoder pristine audio — clearest IVR prompts.

IVR Standard

VOX is what telephony hardware expects — produce from lossless FLAC.

Online Encoding

No Dialogic SDK needed — convert FLAC to VOX in your browser.

How to convert FLAC to VOX

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose vox or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your vox file right afterwards

About formats

FLAC (Free Lossless Audio Codec) delivers mathematically perfect audio reproduction at roughly half the size of an uncompressed WAV file. Maintained by the Xiph.Org Foundation and released in 2001, it quickly became the de facto open standard for lossless music archival. The encoder applies linear prediction to model each audio block, then codes the residual through Rice partitioning — exploiting the statistical distribution of prediction errors for strong compression without discarding data. Bit depths up to 32 and sample rates up to 655 kHz are supported, exceeding the requirements of high-resolution recordings. Hardware support is extensive: smartphones, car stereos, Blu-ray players, and virtually every desktop media application decode FLAC natively. Streaming services such as Tidal and Amazon Music use FLAC for lossless tiers, underscoring industry trust in the codec. Three standout benefits make FLAC compelling. First, complete bit-for-bit restoration of the original signal upon decoding. Second, embedded metadata via Vorbis comments and album art keeps libraries organized without sidecar files. Third, open-source licensing means no patents or royalties, removing legal friction for developers and hardware vendors.
Initial release: July 20, 2001
VOX is a headerless audio format built around Dialogic ADPCM encoding, widely adopted in telephony, interactive voice response (IVR) systems, and voice mail platforms since the 1980s. Each audio sample is compressed into 4 bits using an algorithm developed by Oki Electric and implemented in hardware on Dialogic Corporation's telephony interface cards. VOX files typically use a sampling rate of 6000 or 8000 Hz, producing extremely compact recordings optimized for speech intelligibility rather than musical fidelity. Because the format carries no header, playback software must know the sample rate and encoding parameters in advance — a trade-off that reduces overhead but demands careful file management. The primary advantage of VOX is storage efficiency: a one-minute voice recording at 8 kHz occupies roughly 240 KB, making it practical for systems storing thousands of prompts. Dialogic ADPCM conforms to the ITU-T G.726 standard, ensuring interoperability across telephony equipment from different vendors. Even as modern call centers migrate to IP-based systems with codecs like Opus), vast libraries of VOX recordings persist in legacy IVR deployments and compliance archives worldwide.
Initial release: 1983

Frequently Asked Questions

Why convert FLAC to VOX?

VOX (Dialogic ADPCM) is the IVR standard. Lossless FLAC produces the cleanest possible telephony voice prompts.

What uses VOX?

Dialogic boards, IVR platforms, PBX systems, and call center audio infrastructure consume VOX files.

Is VOX good for music?

No — VOX is speech-optimized at 4-bit ADPCM. It handles voice well but degrades music.

Does FLAC improve VOX quality?

Yes — lossless input means cleaner ADPCM encoding with no stacked artifacts.

Can I batch convert?

Upload all FLAC voice prompts and encode to VOX at once.

FLAC to VOX Quality Rating

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