My brain, being over helpful this morning, identified the sound of the toast going into the toaster with the first drumroll of the 20th Century Studios fanfare.
And thus I discovered that of course there is an extensive Wikipedia chapter on that fanfare and its history, and that George Lucas asked John Williams to set the Star Wars main theme in the key of Bb major, the same key as the fanfare.
\ https://en.wikipedia.org/wiki/20th_Century_Studios
May the toast be with you.