Acoustical consultant: Franklin City’s two Larson Davis meters likely insufficient; recommends site visit and mitigation study

An acoustical consultant told Franklin City officials that the city’s two Larson Davis sound level meters could be integrated into a broader monitoring system but are likely insufficient on their own and that a site visit during an event and a detailed noise‑control study are needed to identify effective mitigation.

The consultant said the first step would be to review the project specifications, visit the site while a loud event is occurring if possible, and collect additional monitoring data before recommending equipment or mitigation. “Two locations are most likely not sufficient,” the acoustical engineer said, adding that monitoring should focus on noise‑sensitive property lines and worst‑case receptor locations.

Why it matters: city staff and residents seeking real‑time alerts, law enforcement access to data, or enforceable certification of compliance need a monitoring plan and specifications that match those use cases. The consultant said many brands require proprietary platforms and that Larson Davis equipment can be costly to operate for real‑time alerting, so the city should weigh integration versus installing different monitors.

The consultant described the proposed engagement as consultative: review existing specifications, assess existing Larson Davis meters for integration, perform a site visit (preferably during an event), collect data from multiple positions, then model and recommend mitigation measures. The consultant said a local technician would be assigned to troubleshoot and support on‑site work and that the firm could be on site within days of contracting depending on schedule.

On monitoring coverage and technical approach, the consultant recommended selecting multiple monitor positions that capture noise‑sensitive receptors rather than relying on only two fixed meters. “Sometimes…not necessarily at the closest property line, it depends on the elevation of the ground and other factors,” the engineer said, noting three‑dimensional modeling and color maps are common deliverables.

Timing and deliverables: the consultant estimated that once all data are collected and project specifications are finalized, a completed study with recommendations could be produced in roughly three to six weeks, with possible expedited timelines depending on schedule. The consultant also said routine monitoring and a formal report are typically separate priced items; a final report would include signed certification and graphics of the collected data.

Mitigation options described include temporary and permanent measures—fence‑mounted noise blankets, enclosures for loudspeakers, changes to PA system orientation or type, barriers, and, where applicable, active noise control. As an example, the consultant said a typical fence‑mounted noise blanket can reduce mid‑ and high‑frequency levels by about 20 to 25 dB, but cautioned that low frequencies (common in loudspeaker music) are harder to mitigate and may require enclosures or more permanent barriers. The consultant warned that incremental cost increases are steep as more reduction is sought.

Next steps discussed in the meeting were review of the city’s specification document, determination whether to integrate the existing Larson Davis meters or deploy alternative equipment, scheduling a site visit (ideally timed with a loud event), and agreement on the scope and price for a study and any monitoring/reporting services. If contracted, the consultant said they would advise the city on cost, expected decibel reductions at identified receptor locations, and produce drawings and a mitigation plan.

No formal vote or decision was recorded during the discussion; the remarks were presented as consultant recommendations and options to be considered by Franklin City staff.