Sound Expert Discusses Noise Control At RPB Amphitheater

The Royal Palm Beach Village Council heard a report last week on controlling the noise that will emanate from the new Royal Palm Beach Commons Park amphitheater.

Construction on the amphitheater will begin soon. Some residents who live near the park complained in April that the noise from bands and other special events was unbearable, and the council directed its architects to look for ways to mitigate the noise.

At the July 14 meeting, Village Engineer Chris Marsh said a study was still underway, but a noise consultant had already done work on sound control at the park with a good degree of success.

“We’re going to go over the recommendations from the noise impact study, and the recommendations from the study are to continue to evaluate it for an additional six months,” Marsh said. “At that point, we will come back and make a final recommendation on the sound parameters.”

Rusty Cadaret is an acoustical engineer with TSG Design Solutions, hired by the architects to study the sound characteristics for the planned amphitheater. After meeting with staff and taking input, Cadaret said he attended several smaller events at the amphitheater, as well as the village’s Fourth of July event, which is traditionally the largest event of the year.

“We took what was said to heart, so we spent some time at the subsequent events out there taking sound pressure readings, and did a fair amount of work in predictions and analysis,” he said.

Cadaret’s firm published a detailed technical report, but he went over the executive summary with suggestions on how to improve the current conditions and create a mitigation strategy.

The best and most effective method to reduce the impact of noise is to limit its creation, he said. The next most effective way is to control the noise that is created, and a less effective way is to build barriers around the perimeter.

“The best way to not have a sound problem is to not make the problem,” he said. “The next thing to do if you’re going to make noise, is to control the noise, and then the last way is once you have the sound out there is to try and stop it. That is the most expensive and least effective.”

Cadaret recommended controlling the noise by using specially designed speakers positioned up high to direct the sound down to the intended audience, especially in the low frequency range, which is found most objectionable to unintended recipients. He also recommended using sound monitoring equipment placed at specific distances from the stages.

“We know that low frequency is a problem,” he said. “We know that controlling low frequency is very hard. There is technology out there to direct low-frequency energy.”

Cadaret told the council that he had spoken with the sound provider on the Fourth of July about arranging speakers in a cardioid configuration that cancels low-frequency sounds with noticeable success. “Unfortunately, the skies opened up before we were able to get some real objective measurements,” he said. “Subjectively, I can tell you it worked quite well.”

Cadaret said landscaping is also being worked into the amphitheater project to limit sound escaping from the park, but stressed that controlling the source is much more effective. Acoustic treatments within the stage itself will also help.

“The goal there is to have acoustic treatments within the stage so musicians don’t have to play as loud,” he said.

They also looked at building a wall around the spectator area but found it would need to be much too large to do any good. “We don’t think that’s a really good way to go,” he said.

Cadaret concluded by saying that there’s no guarantee that a sound mitigation strategy would be completely satisfactory to everyone, and that the imposition of sound level restrictions could have a negative impact on the performance quality and result in audience dissatisfaction. The goal is to find a balance between the two through continued monitoring and community engagement.

Councilman David Swift and Vice Mayor Jeff Hmara both said they were pleased with the result of the Fourth of July celebration.

Hmara said he had monitored the sound with a cell phone app.

“It seems like we may have the right combination of things now, and while I didn’t step behind the stage and use my highly precise sound app, the measurements that I took were significantly less than what we had experienced during the previous event,” he said.

Mayor Fred Pinto said he was glad to see that the study was focusing on low-frequency sound, because that was the major complaint from residents around the park.

Marsh said speaker towers will be part of the amphitheater design as the result of the study so far, but much of the sound design is still ongoing. He said landscaping will be installed near the end of construction.

“Managing the noise at the source is what we see as the policy,” Marsh said.