A physics professor at MIT with an interest in acoustics, Bolt started a consulting firm with another MIT professor, Leo Beranek, and worked on such projects as doing an audio analysis of the JFK assassination, the “18.5 minute gap” in Nixon’s White House tapes, and improving the sound in concert halls.
In later years, after the addition of one of his former students, Robert Newman, the firm of Bolt, Beranek and Newman, better known as BBN, designed the first computer modem in 1963, helping computers communicate with each other. This led to work on the ARPAnet, which became the Internet. BBN helped develop e-mail and, in 1971, one of BBN’s researchers chose the “@” sign for e-mail addresses. Bolt retired in 1976. He died on January 13. He was 90.