WAV to SLN Converter

Create Asterisk PBX signed linear audio from WAV

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PBX-Ready Format

Produce SLN files that Asterisk PBX reads natively — drop them into the sounds directory and they work immediately.

Bulk Conversion

Convert an entire library of WAV prompts to SLN simultaneously — set up your phone system audio in one workflow.

No CLI Tools Needed

Convert WAV to SLN in the cloud — skip installing SoX on your PBX server just for audio format conversion.

How to convert WAV to SLN

1

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

2

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

3

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

About formats

WAV (Waveform Audio File Format) is an uncompressed audio container jointly developed by Microsoft and IBM, first published in August 1991 alongside Windows 3.1. Built on the Resource Interchange File Format (RIFF), WAV stores audio data — most commonly as linear pulse-code modulation (LPCM) — together with metadata describing sample rate, bit depth, and channel count. This straightforward structure has made WAV the de facto standard for uncompressed audio on Windows and a universally accepted interchange format across virtually every operating system, audio editor, and media player in existence. CD-quality WAV files use 16-bit samples at 44.1 kHz stereo, while professional workflows routinely employ 24-bit or 32-bit float samples at rates up to 192 kHz. A major advantage is zero-loss fidelity: because standard WAV applies no compression, the stored data is an exact digital representation of the original recording, making it the preferred choice for mastering and archiving. WAV also supports embedded metadata through INFO and BWF chunks, enabling timestamping and production notes. The main trade-off is file size — one minute of CD-quality stereo occupies roughly 10 MB — and the 32-bit RIFF structure imposes a 4 GB limit, though RF64 removes that ceiling.
Developer: Microsoft and IBM
Initial release: August 1991
SLN (Signed Linear) is a headerless raw audio format storing 16-bit signed linear PCM samples at 8000 Hz mono, most closely associated with Asterisk — the open-source PBX framework developed by Digium (now Sangoma Technologies). Within Asterisk, SLN serves as the native internal audio representation: every codec transcoding operation passes through signed linear as an intermediate step. This makes SLN the backbone of Asterisk's codec translation architecture. The format contains nothing but raw samples — no headers, no metadata, no framing — so parameters must be known in advance. While this lack of self-description might seem limiting, it is actually an advantage in telephony where sample format is fixed by convention and every overhead byte matters across thousands of simultaneous channels. The 8000 Hz rate aligns with the G.711 standard for traditional telephony, capturing the full 300-3400 Hz voice band. Asterisk also supports extended variants (sln16, sln32, sln48) for wideband audio. SLN files require no decoding — just direct memory mapping — making them ideal for real-time mixing, conferencing, and prompt playback in high-density VoIP environments.
Initial release: 1999

Frequently Asked Questions

Why convert WAV to SLN?

Asterisk PBX uses raw signed linear PCM as its native audio format. Phone prompts and hold music must be in SLN for direct Asterisk playback.

What uses SLN files?

Asterisk, FreePBX, and compatible VoIP platforms consume SLN files directly as system sounds, prompts, and music-on-hold.

What sample rate should I choose?

Standard Asterisk uses 8 kHz mono (sln). Wideband extensions use 16 kHz (sln16). Match your system dialplan configuration.

Is SLN just raw PCM?

Yes — SLN is headerless raw signed linear PCM data. No container overhead means zero decoding latency for the PBX.

Can I batch-convert for a phone system?

Upload all your WAV prompts and convert them to SLN at once — deploy a complete set of PBX audio files in one session.

WAV to SLN Quality Rating

4.9 (147 votes)
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