The family of sound pioneer Ray Dolby has donated £85m from his estate to Cambridge University.
The US-born engineer was best known for his work in developing noise reduction and surround-sound technology. He died in 2013 aged 80.
The donation will go to the Department of Physics' Cavendish Laboratory where Dr Dolby worked on his PhD in 1961.
It is the second largest gift to the university in its 808-year history after Bill Gates donated $210m in 2000.
Dr Dolby came to Cambridge as a Marshall Scholar in 1957 and studied physics at Pembroke College which itself received £35m from his estate in 2015 .
The bequest will complete the redevelopment of the Cavendish Laboratory, known as Cav III , with the Ray Dolby Centre set to open in 2021/22.
A research group and a professorship in physics will also be named in honour of the inventor.
Professor Andy Parker, head of the Cavendish, said: "In addition to serving as a home for physics research at Cambridge, it will be a top-class facility for the nation.
"This gift is the most significant investment in physics research in generations."
Dr Dolby's widow, Dagmar, said the university played a pivotal role in his life "both professionally and personally".
Cambridge Vice-Chancellor Professor Stephen Toope also described the donation as "a fitting tribute to Ray Dolby's legacy".
"His research paved the way for an entire industry," he said.
"A century from now, we can only speculate on which discoveries will alter the way we live our lives and which new industries will have been born in the Cavendish Laboratory, in large part thanks to this extraordinarily generous gift."
The multimillion-pound donation also pushes Cambridge University's £2bn fundraising campaign - which was launched in 2015 - over the halfway mark.
The campaign will support students and university facilities, as well as boost its international reputation.