🎧 Free tool · No sign-up · No upload

WOCOM Audio File Converter

Turn any recording — MP3, M4A, OGG, FLAC or an oddly-formatted WAV — into the exact file your phone system will accept: WAV · PCM · 8000 Hz · 16-bit · mono. That is the format used for IVR and auto-attendant prompts, voicemail greetings, and music on hold on WOCOM Cloud PBX, Asterisk, FreePBX, 3CX, FusionPBX / FreeSWITCH and virtually every other IP PBX.

Conversion happens inside your browser using the Web Audio API. Your recordings are never uploaded to a server, so you can safely convert client greetings, internal announcements and recorded calls.

Target format
ContainerWAV (RIFF)
EncodingPCM
Sample rate8000 Hz
Bit depth16-bit
ChannelsMono
Bit rate128 kbps
1 · Choose your phone system

Output: WAV · PCM · 8000 Hz · 16-bit · mono — the standard prompt format for WOCOM Cloud PBX.

2 · Add your audio files
🎵
Drag & drop your audio files here
or click to browse — MP3, WAV, M4A, AAC, OGG, FLAC, WebM, AIFF
Up to 150 MB and 60 minutes per file.

🔒 Private by design. Every file is decoded, resampled and re-encoded on your own computer. Nothing is sent to WOCOM or to any third party, and nothing is stored.

What audio format does my PBX need?

Almost every IP PBX inherited the same requirement from the traditional telephone network: calls travel as 8 kHz, 16-bit, mono audio (G.711), so prompt files are stored the same way. A 44.1 kHz stereo MP3 exported from a phone or a studio simply is not what the dialplan expects — which is why uploads get rejected, or play back too fast, too slow, or as silence.

PlatformRequired prompt formatWhere the files go
WOCOM Cloud PBXWAV · PCM · 8 kHz · 16-bit · monoIVR / auto attendant, voicemail greeting, music on hold
AsteriskWAV · PCM · 8 kHz · 16-bit · mono (also accepts G.711 μ-law/A-law and GSM)/var/lib/asterisk/sounds/custom/
FreePBXWAV · PCM · 8 kHz · 16-bit · monoAdmin → System Recordings; Music on Hold
3CXWAV · PCM · 8 kHz · 16-bit · monoDigital receptionist prompts, queue & on-hold audio
FusionPBX / FreeSWITCHWAV · PCM · mono · 8 kHz or 16 kHzRecordings, IVR menus, music on hold
Issabel / ElastixWAV · PCM · 8 kHz · 16-bit · monoSystem Recordings (Asterisk-based)
VICIdialWAV · PCM · 8 kHz · 16-bit · monoAudio Store (Asterisk-based)
Grandstream UCMWAV · PCM · 8 kHz · 16-bit · mono (≤ 5 MB)Custom prompts / IVR prompts
YeastarWAV · PCM · 8 kHz · 16-bit · monoPrompt management

Systems that accept a wider range of input usually transcode server-side — and that transcode is where quality is lost. Feeding the PBX a correctly-prepared 8 kHz mono file gives you the cleanest possible result on the call.

How to convert your file

  1. Pick your phone system above. The correct sample rate and encoding are applied for you — 8 kHz for Asterisk, FreePBX, 3CX and WOCOM Cloud PBX; 16 kHz where FreeSWITCH-based systems can use it.
  2. Drop in your recording. MP3, M4A, AAC, OGG, FLAC, WebM, AIFF and any WAV variant are all accepted — including 24-bit, 32-bit float, μ-law and A-law WAVs that other converters refuse.
  3. Leave “normalise volume” ticked unless you have already mastered the audio. Prompts recorded on a phone are usually far too quiet against the rest of the call.
  4. Preview the result in the player. What you hear is the 8 kHz mono file itself, so it is a fair preview of how it will sound to a caller.
  5. Download and upload it to your PBX — IVR prompt, auto attendant, voicemail greeting, queue announcement or music on hold.

Converting a whole prompt set? Drop in every file at once and use Download all (.zip). Filenames are cleaned automatically — lower-case, hyphenated, no spaces or accents — because spaces in filenames are a common cause of failed uploads and broken dialplan references.

Common prompt problems — and what causes them

The prompt plays too fast, high-pitched or “chipmunk”

The file is at 44.1 or 48 kHz but the PBX is playing it as 8 kHz. Re-convert it here to 8 kHz.

The prompt plays too slowly or sounds deep

The opposite mismatch — an 8 kHz file being played at a higher rate, usually after a bad conversion elsewhere.

The upload is rejected as “invalid format”

Usually a stereo file, an MP3 renamed to .wav, or a WAV with a non-PCM codec inside it. Converting here rewrites the container and the audio properly.

Callers hear silence, or only one side

A stereo file where the audio sits on one channel only. Downmixing to mono — which this tool always does — fixes it.

The greeting is far quieter than the caller’s voice

Recording level was too low. Tick “normalise volume” — the file is lifted to a consistent peak just under clipping.

There is a click or pop at the start

A hard cut mid-waveform. Every file converted here gets a short fade in and out to remove it.

Getting a professional-sounding prompt

At 8 kHz there is no room to hide — a phone line reproduces roughly 300 Hz to 3.4 kHz, so room echo, background noise and mouth noise are more obvious on a call than they are in your headphones. A few things make a large difference:

  • Record in a small, soft room — carpet, curtains and furniture. Bare offices and boardrooms sound hollow over the phone.
  • Stay 15–20 cm from the microphone and slightly off-axis to avoid popping your P’s.
  • Keep prompts short. Menu options: under 20 seconds. Greetings: under 10. Callers press a key long before a long greeting ends.
  • Lead with the business name, then the options — “Thank you for calling <business>. For sales, press 1…”.
  • Speak slightly slower than normal and leave a beat of silence between options.
  • Music on hold: pick something licensed. Commercial music generally cannot legally be used as hold music without a licence.

Rather not manage prompt files at all?

WOCOM Cloud PBX handles IVR menus, greetings and music on hold for you — and every plan includes WOCOM AI, an AI receptionist that answers in natural conversation instead of asking callers to press 1. Licensed carrier, Jamaican support, local numbers.

Explore Cloud PBX Meet WOCOM AI Talk to us

Audio converter — frequently asked questions

WAV (RIFF container), PCM encoding, 8000 Hz sample rate, 16-bit sample size, mono — which works out to a 128 kbps bit rate. This is the standard for WOCOM Cloud PBX, Asterisk, FreePBX, 3CX, Issabel, VICIdial, Grandstream UCM and Yeastar. FusionPBX and other FreeSWITCH-based systems also accept 16 kHz mono.
No. The conversion runs entirely inside your browser using the Web Audio API. Your file is read from disk, processed in memory and saved back to your computer. Nothing is transmitted to WOCOM or to any third party, and nothing is stored.
Yes. Drop the MP3 in and it is decoded, downmixed to mono, resampled to 8000 Hz and re-encoded as 16-bit PCM WAV. The same works for M4A, AAC, OGG, FLAC, WebM, AIFF and WAV files that are already in the wrong format.
The file is at a higher sample rate than the PBX expects — typically a 44.1 kHz recording being played back at 8 kHz. Converting it to 8000 Hz mono fixes the playback speed and pitch.
Each file can be up to 150 MB and 60 minutes long. Because the conversion runs in your own browser, a larger file would be decoded into your computer's memory, and the limit keeps a very long recording from exhausting the browser tab. Your PBX may impose its own, smaller limit — Grandstream UCM, for example, caps custom prompts at about 5 MB. An 8 kHz 16-bit mono WAV is roughly 1 MB per minute.
Five conversions per hour, which covers a typical set of IVR prompts — a main greeting, an after-hours message, a voicemail greeting and a couple of queue announcements. The allowance refills on a rolling basis, so a slot frees up an hour after each conversion. If you are setting up a full auto-attendant tree or a music-on-hold library, contact WOCOM: Cloud PBX customers have their prompts loaded for them.
Yes. Drop in several files together — each is converted with the same settings and you can download them individually or together as a ZIP archive. A batch counts against the same five-per-hour allowance, one slot per file.
Some Asterisk and FreeSWITCH deployments prefer prompt files stored in the same codec the calls use, which avoids a transcode at playback time. Choose u-law for North American and Caribbean networks and A-law for European networks. If you are unsure, 16-bit PCM is the safe choice and works everywhere.
Yes — music on hold, auto-attendant menus, voicemail greetings, queue announcements and after-hours messages all use the same format. Remember that commercial music usually requires a licence before it can be used as hold music.
No. This tool replaces the usual Audacity export-settings routine or an ffmpeg command line. Nothing to install and nothing to configure — but the equivalent command, if you prefer the terminal, is: ffmpeg -i input.mp3 -ar 8000 -ac 1 -acodec pcm_s16le output.wav
Any current version of Chrome, Edge, Firefox or Safari, on desktop or mobile. It uses the standard Web Audio API with no plugins or extensions.

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