Three masked men dressed mostly in black came out of the woods behind Southern Tracks recording studio and attacked Ament and employee Mark Anthony Smith as they arrived in a rented Jeep late last month, DeKalb County police said.
Police say the men smashed three of the Jeep's windows and grabbed a Blackberry and two computers and demanded money. Ament jumped out of the passenger side and tried to run, but one of the men knocked him to the ground and stole his passport.
The men got away with $3,000 cash, along with computers and other equipment worth more than $4,000. Paramedics treated Ament for head injuries.
Surveillance cameras recorded the incident but no one has been arrested.
Pearl Jam management had no comment Thursday.
Southern Tracks is a studio in north Atlanta that's worked with artists including Aerosmith, Stone Temple Pilots and Bob Dylan.
Rolling Stone reports Pearl Jam is working on an album they plan to release themselves in the United States.
Copyright 2009 The Associated Press.