In a statement Friday, Butts said the elevated stage in the plaza was determined to be a "major contributor to the issue."
"Consequently, no stages will be permitted in this area for future events," Butts said.
He also said the city will "require even greater sound engineering with a more comprehensive plan when it comes to addressing sound and bass frequency management."
Complaints began pouring in Saturday from some South Bay communities, most notably neighboring El Segundo, with residents reporting vibrations and booming noise coming from the festival, which featured acts such as Nelly Furtado, Disclosure and Camden Cox.
South Bay residents complain of loud noise, migraines from HARD Summer Music Festival in Inglewood
Butts said the city was "perplexed" by the issue, given the number of previous outdoor concerts held at the Hollywood Park property without complaint. He said city officials worked with festival organizers between Saturday and Sunday to find ways of alleviating the problem, which primarily focused on certain "bass frequencies."
"These frequencies can be affected by stage position, reflection off of buildings and atmospheric conditions including wind," Bass wrote in a statement. "City authorities engaged the event promoter and the venue and implemented several critical adjustments to each stage and established enhanced monitoring plans for overall sound and bass levels. Additional sound engineers were strategically positioned in areas of concern from Saturday afternoon through Sunday and were promptly dispatched to make necessary adjustments in real time.
"As a result, a significant decrease in call volume was observed on Sunday in the initially impacted areas," he said. "However, some areas continued to experience bass vibrations. Moving forward, and with the lessons learned the past weekend, we are prepared to better monitor and supervise future event organizers to minimize the sound and vibration impact on the community outside the venue."
The HARD Summer festival featured four outdoor music stages positioned outside SoFi Stadium, located mainly in the surrounding parking lots.