Living in Westchester, Chris Bankoff said he’s grown accustomed to two types of noise: the occasional house party of Loyola Marymount University students and the roar of plane engines taking off from Los Angeles International Airport .
He didn’t expect to hear low-end music on Aug. 2 from HARD Summer, a house and techno music festival held at Hollywood Park in Inglewood, about five miles from Bankoff’s home.
When he first heard the beat that Friday, he thought there was a party nearby, so he ignored it. But the sound returned the next afternoon and was louder than the day before, Bankoff said.
“I can hear the change in rhythm,” he said. “It’s like someone parked in front of a house and played loud music in the car.”
In North Redondo Beach, about 9 miles from the recreation site, Sondra Segall thought she heard construction work. The noise didn’t bother her, but she wondered how she heard it.
Residents in Manhattan Beach, El Segundo and Hermosa Beach also took to the Nextdoor app and Reddit to ask or complain about the noise. The El Segundo Police Department received more than 100 calls on Friday and 200 on Saturday; on Sunday, the number dropped to 50, possibly in response to community alerts and social media posts. respond.
Neither festival organizers Insomniac Events nor Hollywood Park responded to requests for comment before publication.
Although Inglewood’s noise ordinance limits the volume of concerts, it said those limits don’t apply to events in Hollywood Park that end at midnight. So HARD Summer’s artists ended their set around 11 p.m., performing at a volume that probably matched or exceeded that of an airport runway.
HARD Summer organizers told KABC-TV in a statement, “While we always operate within legally acceptable decibel levels, we have sound monitors deployed on site to monitor and respond to all noise complaints.”
The farther a sound wave travels from the source, the less energy it has. So even if the music is amplified to the threshold of pain, the volume should be lower than the volume of quiet conversation within a few miles of the concert.
So, what happened?
El Segundo City Manager Darrell George said in a statement that he contacted Inglewood City Manager Mark Weinberg, who said event organizers made a mistake in setting up the performance space, exacerbating the situation. “Bass Reverb”.
Inglewood Mayor James T. Butts Jr. issued a statement nearly a week after the first complaint, saying the sound and vibration issues experienced were “related to certain bass frequencies.” Can be affected by “stage location, building reflections and atmosphere.” Butts added that erecting the stage on the elevated American Airlines Plaza “is a major contributor to this problem” and said that future concerts will be prohibited in the area.
Vincent Olivieri, a professor of sound and design at the University of California, Irvine, said that based on anecdotes shared by residents, people in the South Bay are not hearing an increase in bass reverberation.
“‘Reverberation’ refers to the millions of reflections from different surfaces that give a space its unique sound,” explains Olivieri. That’s why the cave’s hard stone walls cause so many acoustic reflections that it sounds like a cave rather than a living room, he said.
“The reverberation explanation also doesn’t explain why only people southwest of the venue seemed to hear it,” he said.
If Inglewood’s explanation doesn’t hold up, how could residents nine miles southwest of the venue hear the low-frequency vibrations of “Better Summer?” Audio engineering and acoustics experts have theorized how sound travels so far.
how sound travels
The festival’s musical performances take place on five stages set up in parking lots surrounding SoFi Stadium. Tony Hoover, principal at McKay Conant Hoover Acoustics and Audiovisual Consultants, said that in this type of outdoor performance, there are no walls to interfere with the propagation of sound outwards.
Unlike indoor entertainment venues, there is no roof to contain the sound, he said.
Barry Rudolph, president of the Los Angeles chapter of the Society of Sound Engineers, said deep bass is an important part of hip-hop, techno and electronic music. He said he was convinced the festival used powerful amplifiers and huge speakers to reproduce the sound fully and at high volume.
“Loud and long sound waves can vibrate surrounding local structures, which resonate with this additional sound energy,” he said, exacerbating the problem of sound seeping from the stage into the community.
Rudolph said it was like hearing a car drive down the street and the sound from the stereo rattling the windows – you heard the music before the car came into view.
Still, Rudolph doubts the low frequencies from the “sweltering summer” can travel as far as 9 miles. More believably, he said, the thumping bass traveled about a mile in all directions from Hollywood Park (low frequencies, unlike high frequencies, are omnidirectional, he said).
However, many people far away from Hollywood Park said they heard the festival’s rhythmic rumble on Friday and Saturday.
Hoover said it was not unheard of for the sound to travel for miles, but he was confused when he learned the thumping sound was heard by people nine miles away.
He described the sound coming from Hollywood Park as “kind of like a giant sound bubble that just keeps getting bigger and bigger.” But as the sound bubble grows, it gets weaker, which is why the volume drops as you move away from the source of the sound.
However, bubbles can be reshaped by wind and temperature, both at the ground level and in the air layer above them.
Hoover said temperature plays a role especially in warm or hot weather.
After the sun sets, the air at ground level becomes cooler, but the air at higher altitudes is usually much warmer (a “temperature inversion”). Because sound waves travel at different speeds in warm and cold air, these different temperature zones can cause sound waves to bend, or refract downward, said Jason Corey, associate professor of music at the University of Michigan.
Olivieri further explained the phenomenon of temperature inversion, saying that sound waves, or sound energy, are affected by the microclimate.
Imagine a thermal dome on a smaller scale. Under the right conditions, collections of hot air can sometimes act as overhead mirrors, confining sound wave energy downward. This happens especially during summer festivals.
When sound wave energy leaves an outdoor concert venue, some of it travels upward into the atmosphere. Here, Olivieri said, sonic energy leaving the “sweltering summer” could hit a small patch of warm air between the venue and the affected neighborhood.
“That warm air acts as a kind of sound mirror and refracts [the sonic energy] Immediate return” into affected communities]he said.
Corey agrees, saying that during a temperature inversion, “sound from the concert venue travels upward into warmer layers of air and curves downward after passing through buildings and other obstructions, reaching distances away from the music. would be miles away on the ground.
Hoover was skeptical, saying the wind and many other factors would have to be perfectly aligned to create an inversion effect, especially over such long distances. But Olivieri said if the bass signal is louder than it should be, and the sound is reflected back to communities in the Southwest from hot microclimate systems, that could help explain why those communities are not in others.
Dave Revel, president of Technical Multimedia Design, a consulting firm that often helps venues reduce noise, said the distant rumble at concerts is not a new phenomenon but has become more common due to advances in concert sound technology. becoming more and more common.
He added: “This is a logical advance in technology, but it creates challenges with community noise because now you have very large, powerful sound systems that can reproduce a wide range of frequencies.”
At events at the Rose Bowl and Fairplex, Revel said the multimedia technology design firm found that people four miles away could hear the music, especially the bass.
The role of noise regulations
Another potential factor in the incident is Inglewood’s noise ordinance.
Volume is measured in decibels or sound pressure units. But there are different standards for measuring decibels when regulating noise, with one focusing on the frequency range of human speech and another being more suitable for the entire frequency range, including bass frequencies.
Revell said generations of community noise ordinances were based on previous standards that focused on frequencies common to human speech. “They never expected the concert [would have] Bass is in it.
The city of Inglewood’s ordinance falls into this category. The challenge, Revell said, is that the standard it relies on “doesn’t take into account all frequencies, and certainly doesn’t take into account low frequencies that travel farther.”
Concerts and music festivals can operate well within the law because “the law largely ignores bass.”
In 2015, Revel’s company was hired by the Pomona Fairplex to assist with noise mitigation at the HARD Summer music festival in July, after receiving complaints about “unbearable noise levels” several months earlier, according to the Daily Gazette. complaint.
Revell said he remembers measuring the sound during the event.
“We were actually within community noise limits for the entire concert, but people’s windows were rattling,” he said. “People who live next door to the concert, their windows are rattling because the bass is so crazy.”
