In his six years of independent practice Sandy Brown raised the acoustic design of commercial sound recording studios to an internationally known product and built studios for many leading musicians including Cream, Eric Clapton and the Rolling Stones. Sandy was asked back to his home town of Edinburgh in 1972 to act as acoustic consultant for the Edinburgh Opera House project and used for the first time outside the BBC, an 1/8th scale physical acoustic model. This was the first use of this technique, developed by his colleagues and later partners, at the BBC Research Department, in the design of an auditorium.

Sandy Brown Associates was the first major UK buildings acoustics consultancy practice. Sandy's work, and that of the practice that survives him, has had a major influence on the development of building acoustics both in the UK and throughout the world.

Sandy Brown Associates became Sandy Brown Associates LLP, a limited liability partnership, on 1 April 2004.