SLN to IRCAM Converter

Move Asterisk SLN audio into IRCAM research file format

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Academic Research Format

Convert SLN telephony recordings into the IRCAM format — purpose-built for scientific audio analysis and research.

Telephony to Research

Bridge Asterisk PBX systems and academic audio research by packaging SLN recordings in the IRCAM container.

Cloud-Based Conversion

No research software installation needed. The SLN to IRCAM conversion runs on our servers via your browser.

How to convert SLN to IRCAM

1

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

2

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

3

Let the file convert and you can download your ircam 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
IRCAM sound files originate from the Institut de Recherche et Coordination Acoustique/Musique — one of the world's foremost computer music laboratories, founded by composer Pierre Boulez in Paris. The format was created in the early 1980s to serve the research needs of IRCAM and has since been adopted by academic and artistic communities working at the intersection of science and sound. An IRCAM file begins with a 1024-byte header containing a magic number, sample rate, channel count, and an encoding type field that supports linear PCM (16/32-bit integer and 32-bit float), mu-law, and A-law variants. The header block also accommodates free-form annotation text, allowing researchers to embed experiment metadata directly in the audio file. Because the payload is uncompressed by default, recordings maintain full fidelity through successive analysis and resynthesis cycles — essential in psychoacoustic experimentation. Software such as Csound, libsndfile, and SoX reads and writes the format natively. Key advantages include a well-defined header that eliminates parsing ambiguity, support for floating-point samples essential in scientific DSP work, and deep roots in the computer music community ensuring continued tooling.
Developer: IRCAM
Initial release: 1983

Frequently Asked Questions

Why convert SLN to IRCAM?

IRCAM format is used at the Institut de Recherche et Coordination Acoustique/Musique for audio research. It suits academic audio analysis.

What software supports IRCAM?

SoX, CSound, and research tools from the IRCAM institute handle this format. Some professional audio editors can also import it.

Is IRCAM suitable for general playback?

IRCAM is a research format. It works well in academic and experimental contexts but is not designed for everyday media playback.

Can I batch convert SLN to IRCAM?

Upload several SLN files at once and convert them all to IRCAM in a single batch — great for preparing research datasets.

Is the conversion private?

Your SLN files are deleted after processing, and IRCAM outputs are removed from servers within 24 hours.