Guest post by Roland Deiser and Sylvain Newton Twenty years ago, on November 18th, 1993, the music band Nirvana agreed to an unplugged performance at the Sony Music Studios in New York City. It was part of a television series called “MTV Unplugged”, which invited popular music groups to perform their songs “naturally”. Unlike in a studio, the sound of instruments would not be electronically amplified and engineered; the artists had rather to rely on the “raw” performance of a…