SHN is short for Shorten. It is a lossless compression algorithm for digital music. It was developed by SoftSound (www.softsound.com). It compresses music files 1/2 to 1/3 of their original size, maintaining perfect sound quality.
-->TAKE A LOOK TO http://www.etree.org/mkw.html
The mkw Audio Compression Tool (mkwACT) is a free Windows« 95/98/Me and NT/2000 and XP program created for the easy and convenient conversion of WAV audio files to and from various lossless and lossy compressed formats, including Shorten (SHN).