SHN to SPH Converter

Encode Shorten audio as NIST Sphere SPH online

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Specialized Output

Generate SPH from pristine lossless SHN source — clean audio for your specific application needs.

Online Processing

No specialized tools needed — our servers handle the entire SHN to SPH conversion through your browser.

Secure Files

SHN uploads are erased immediately. SPH outputs are purged from servers within 24 hours.

How to convert SHN to SPH

1

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

2

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

3

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

About formats

Shorten (SHN) is a lossless audio compression codec created by Tony Robinson at SoftSound) and first published in 1993, making it one of the earliest practical lossless compressors. The algorithm uses linear prediction to estimate each sample from predecessors, then encodes residuals with Huffman or Golomb-Rice codes. Compression ratios typically fall between 2:1 and 3:1, with the guarantee that decoded output is bit-identical to the original. Shorten gained cultural significance in the late 1990s as the preferred format for trading live concert recordings online — communities like etree.org built entire distribution networks around SHN files, and bands like the Grateful Dead and Phish tacitly endorsed the practice. One advantage was the format's simplicity: encoding and decoding ran fast even on modest Pentium-era hardware. Another strength was deterministic output — the same input always produced the same bytes, making checksums reliable for verifying integrity across thousands of traders. While FLAC eventually superseded Shorten with better compression, seeking support, and embedded metadata, SHN retains historical importance and extensive live music archives in the format still circulate today.
Initial release: 1993
SPH is the file extension for audio stored in the NIST SPHERE (SPeech HEader REsources) format, a standard created by the U.S. National Institute of Standards and Technology around 1990. Built for speech research, SPH files carry a 1024-byte ASCII header packed with metadata — database identifiers, channel counts, sample rates, byte ordering, and compression type — making every recording self-describing. The underlying audio is typically 16-bit linear PCM sampled at 16 kHz, though other configurations are permitted. Researchers at NIST, DARPA, and universities worldwide rely on SPH for distributing speech corpora such as TIMIT, Switchboard, and the LDC collections that underpin modern automatic speech recognition systems. A key advantage is that the human-readable header lets scripts parse recording metadata without binary decoding. The format's strict standardization also eliminates ambiguity when sharing datasets across institutions and platforms. Because SPH files store uncompressed PCM, they preserve full audio fidelity — critical when training acoustic models where even small artifacts can skew results.
Initial release: 1990

Frequently Asked Questions

What is SPH?

SPH is a specialized audio format — the standard audio format for speech corpora and linguistic research databases.

Why convert SHN to SPH?

Specific applications require SPH files. Lossless SHN provides clean, artifact-free source material for the conversion.

What handles SPH?

Specialized tools, SoX, and targeted professional software support SPH audio processing and playback.

Is quality maintained?

Starting from lossless SHN ensures no prior compression artifacts — output quality depends on SPH format capabilities.

Is the conversion secure?

SHN uploads are deleted immediately after conversion. SPH results are removed from servers within 24 hours.