On a live concert stage, sound engineers constantly tackle noise issues. Kick drums can bleed into vocal mics, while guitar amps might interfere with monitor feeds. When singers drop mics to their chests, lyrics can disappear. Historically, engineers relied on equalization, compression, volume, and judgment to address these challenges. This summer, the Hollywood Bowl introduced a significant change.
A machine learning system called Source Intelligence, developed by L’Acoustics, offers new solutions. This system listens to each microphone on stage and isolates a singer’s voice from background sounds with unprecedented precision.
“Suddenly, you’re not getting the guitar amp or the drums in that mic,” Fred Vogler said, the Bowl’s principal sound designer.
Technical Achievements
The system can achieve up to 40 decibels of reduction on unwanted noise, which is significantly better than any existing technologies. According to Laurent Vaissié, L’Acoustics’ CEO, this represents a 20 decibel improvement over competitors.
This is part of a broader audio overhaul at the Hollywood Bowl, the most ambitious in a generation. It includes an L Series line array system and a unique immersive surround installation.
Redesign at the Forefront
The L1, L’Acoustics’ flagship line array system, forms the centerpiece of the upgrade. This system employs multiple speaker cabinets in a curved vertical column, allowing precise control of sound direction across a venue. These speaker integrations reduce coherence loss caused by physical gaps.
“When you attach multiple boxes, you create a gap between the speakers,” Vaissié explained.
The new system is 30% smaller but more powerful. For the Hollywood Bowl, addressing noise concerns is crucial due to nearby residential areas. The new setup reduces sound variance from six-nine decibels to around three, enhancing the audience’s experience throughout the venue.
“All the way to the top, you feel like you’re really close to the stage,” said Vaissié.
AI Revolutionizing Live Sound
Source Intelligence utilizes AI to isolate singers’ voices from the live stage environment. This technology originated from a stem-separation algorithm initially intended for DJs, later adapted by L’Acoustics for live sound.
The practicality for mixing engineers is substantial, leading to clear vocals and a cleaner mix. It’s being used by artists like Harry Styles, the Weeknd, and Bruno Mars, demonstrating its impact on major productions.
Immersive Sound Innovation
The Hollywood Bowl also installed an immersive surround sound system, L’Acoustics’ L-ISA platform. This system envelops the entire amphitheater in spatial audio, described as possibly the largest immersive deployment by physical size.
Scott Sugden explained the system’s capability: “We can make a singer feel like they’re inside something.”
Vogler has been experimenting cautiously with this system during performances, aiming for subtlety.
“We just want people to feel like, if you turned it off, something was missing,” he noted.
Looking Forward
Founded in 1922, the Hollywood Bowl continues to aim for exceptional sound quality. The L Series, Source Intelligence, and L-ISA mark the venue’s most significant technological advancement since amplified sound became standard.
Concluding Thoughts
With more than 130 shows scheduled, every artist uses the Bowl’s house system without augmentations. This demonstrates confidence in the infrastructure, affirming a commitment to smarter, more precise, and immersive live music.
The audience simply needs to attend and enjoy these advancements.