Ah, the Spectrum. I saw many shows there- The Who, The Dead, Dylan, Clapton with Muddy Waters, AC/DC, Iron Maiden, Judas Priest, BOC, Rush, The Outlaws, Neil Young, and many others. We called it the Rectum.
Lol...We did, too. Also saw Johnny Winters, Allman brothers a number of times, even the Stones. Remember the concerts had the $3. “Dance Floor” tickets...those were some fun days.
You mentioned The Grateful Dead—speaking of bass players Phil Lesh was an absolute creative freak on the instrument.