Professional Lighting and Sound Association. Website. Publishers of Lighting and Sound America magazine and Lighting and Sound International. They are primarily an association similar to a union, who organise industry wide initiatives, campaigns and support for its members. They are also responsible for the PLASA London show held every September at Earls Court, a major world platform for manufacturers; and for regional conferences around the US: PLASA Focus. They are members of the World Entertainment Technology Federation. PLASA merged with/absorbed the US-based ESTA in 2011.