SMP to SLN Converter

Re-encode Turtle Beach SMP audio as Asterisk SLN format

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PBX System Ready

Convert SMP samples to SLN — the raw audio format that Asterisk VoIP PBX systems use natively.

Cloud Conversion

The SMP to SLN conversion runs on our servers. No Asterisk installation needed for format preparation.

Secure Processing

Your SMP files are deleted after conversion. SLN outputs purged from servers within 24 hours.

How to convert SMP 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

SMP is the native file format of SampleVision, a sample editing application developed by Turtle Beach Systems around 1990. SampleVision was among the first PC-based visual sample editors, letting musicians view waveforms on screen and perform cut, copy, paste, and loop-point editing — capabilities previously limited to expensive dedicated hardware samplers. The SMP format stores 16-bit mono PCM audio along with sampling-specific metadata: loop start and end points, sustain loops, release loops, and MIDI root note assignments. This made SMP files directly useful for creating and exchanging patches between hardware samplers via MIDI Sample Dump Standard (SDS) transfers, which SampleVision automated through its interface. A primary advantage was bridging the PC world with professional sampling hardware from Akai, E-mu, Ensoniq, and Roland — devices that had tiny screens and minimal editing tools. The format also supported common sample rates (22050, 44100 Hz) and brief text descriptions alongside audio data. Though Turtle Beach pivoted to gaming peripherals and SampleVision was discontinued, SMP files persist in vintage sample library archives and can be converted using SoX.
Initial release: 1990
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 SMP to SLN?

SLN is the native audio format for Asterisk PBX systems. Converting SMP to SLN prepares legacy samples for VoIP telephony use.

What opens SLN files?

Asterisk PBX servers use SLN as raw audio. SoX and telephony tools can also process SLN format.

What is SLN exactly?

SLN is signed linear 16-bit raw audio at 8 kHz — the native format used by Asterisk open-source PBX systems.

Can I convert multiple SMP files at once?

Upload a batch of SMP samples and convert them all to SLN simultaneously — efficient for processing entire libraries.

Is the conversion secure?

SMP uploads are deleted after processing, and SLN outputs are removed from our servers within 24 hours.