SLN to AVR Converter

Export Asterisk SLN telephony audio to AVR research format

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Research Format Output

Convert Asterisk SLN telephony recordings into the Audio Visual Research format for academic and historical audio work.

No Local Tools Needed

The SLN to AVR conversion runs on our cloud servers — no vintage research software installation required.

Private and Secure

Telephony recordings stay confidential. SLN uploads are deleted after processing, AVR outputs within 24 hours.

How to convert SLN to AVR

1

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

2

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

3

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

About formats

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
AVR (Audio Visual Research) is an audio format that originated on the Apple Macintosh around 1989, created by the Audio Visual Research company for their editing and synthesis tools. It stores raw audio samples preceded by a fixed-length header containing sample rate, bit depth (8 or 16 bits), channel configuration, and loop point markers. Unlike complex container formats, AVR uses a flat binary structure with no compression, preserving the full waveform quality at the expense of larger files. The format served professional Macintosh audio workstations during the late 1980s and early 1990s, when the Mac platform dominated creative computing. One advantage is uncompressed storage guaranteeing zero artifacts and perfect signal integrity through editing operations. Native loop markers represent another feature, letting sound designers define seamless repetition points within the file — ahead of its time for sample-based music production. Tools like SoX maintain AVR support, ensuring archivists can access and convert these legacy recordings. While eclipsed by WAV and AIFF, AVR remains a notable piece of early digital audio history.
Initial release: 1989

Frequently Asked Questions

Why convert SLN to AVR?

AVR (Audio Visual Research) is used in early audio research contexts. Converting SLN to AVR enables use in legacy research tools and workflows.

What reads AVR files?

SoX, specialized audio research software, and some legacy editors can process AVR format files.

Is AVR a modern format?

No — AVR is a legacy research format. It is mainly relevant for historical audio research or compatibility with vintage analysis tools.

Can I batch convert?

Upload several SLN files at once and convert them all to AVR simultaneously in one session.

Is my data kept private?

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