Fathom: A sonic surface bordering underwater and acoustic worlds

<jats:title>Abstract</jats:title> <jats:p>Fathom is a sound installation by Jane Grant and John Matthias, which was commissioned by the River Tamar Project and was premiered at the Factory Cooperage Building in Royal William Yard, Plymouth, UK in September 2013. Visitors entering the installation were able to hear live and edited sound recorded underwater in Plymouth Sound, a large estuarine body of water from which the Plym, Tamar and Hamaoze Rivers flow into the sea. Six-step ladders in the centre of the installation space surrounded by several additional speakers enabled visitors to climb out of the underwater sonic environment, above the fathom, and hear live acoustic sound relayed by microphones above the water. The artists worked with a team including production manager, Simon Honywill and Martin Audio to create a sonic ‘surface’ 6ft above the ground to enable this to happen. This article will describe how Fathom was created and, in particular, will focus on how the creation of the sonic surface affected the way in which the visiting public interacted with the work.</jats:p>