See the cylinders, left right and above.
As near as I can tell, they were removed circa 1980, again by Frank Gehry, replacing them with spheres.
http://www.unratednyc.com/2009/10/pink- ... moon-tour/
http://gogonotes.blogspot.ca/2009/04/ho ... -1982.html
In 1970 the Hollywood Bowl underwent a visual and sonic overhaul. The acoustics were redesigned with the help of Frank Gehry. The amplification system was replaced by a highly sophisticated sound reinforcement network. The playing area was moved forward. New sound system and acoustical stage enclosure.