I have no idea if this LiveAuctionTalk story is accurate, but it is a fascinating story either way,
“This song is for a friend of mine.” Jimi Hendrix whispered softly into the microphone toward the end of his performance. The songster began to slowly improvise on his guitar. The music he played sounded fragile and grief-stricken.
No one had heard anything like this before from Jimi.
His playing seemed to embrace the anger and hurt the audience and he were both experiencing. His music was common ground, a place where they could come together and mourn.
It was April 5, 1968. The audience knew Jimi’s song was an elegy to Martin Luther King Jr. who had been shot and killed the day before in Memphis.
. . .
His show that night was called one of his greatest unrecorded performances.
This reminds me of Lewis Shiner’s excellent novel, Glimpses, in which unfinished music from Hendrix, Brian Wilson and other start playing from his stereo’s speakers.