Convert and calibrate your prompts to the 3CX format
Drop your files: their loudness is measured, aligned to a shared reference, then converted to the 8 kHz mono 16-bit WAV that 3CX expects. All processing happens in your browser.
Frequently asked questions
What format does 3CX expect exactly?
Uncompressed PCM WAV, 8,000 Hz, mono, 16-bit. An MP3 simply renamed to .wav is rejected: what counts is the file content, not the extension.
How is this different from the 3CX online converter?
The official converter takes one file at a time, up to 50 MB, and the file goes to their servers. It handles the format correctly — and nothing else. Here: the whole batch at once, loudness measured and aligned across every prompt, and no file leaves your browser.
Are my files uploaded anywhere?
No. Conversion runs in your browser through ffmpeg compiled to WebAssembly. You can check for yourself: open your browser Network tab during a run — no request carries audio.
Can I convert several prompts at once?
Yes, and that is the point: processed together, they all come out at the same level. Converted one by one, they come out in the right format but with their original level differences.
Why are my prompts not all at the same volume?
Because they were recorded at different times, on different microphones, by different people. Format conversion does not fix that. EBU R128 normalisation measures the perceived loudness of each file and aligns it to a shared target: −16 LUFS for voice, −20 LUFS for music on hold.
Do I need to install software or create an account?
Neither. The tool is a web page, free, no signup. The alternative method 3CX documents goes through Audacity, which you install and drive file by file.