These are the audio files for Shadowland. Download the file for your part with piano accompaniment, plus the file that is just called Shadowland, which has all parts. The Soprano/Alto and Tenor/Bass lines are only available together, due to the layout of the music.
An MP3 player should recognise the files as being part of an album called MCC July 2013.
In terms of instruments used, the file with all parts has all voice parts using a voice synth. In the individual parts, the piano accompaniment is quiet, and the voice parts are played as saxophone in the Soprano/Alto file, and as a bassoon in the Tenor/Bass file.