February 2012: What’s That Noise?


What did you say? We can’t hear you. At Metropolitan Acoustics, we receive inquiries about noise problems every day. With our 20+ years in the business, we have seen every type of noise problem from poor intelligibility in lecture halls, to sound transmission problems in multi-family buildings, to exterior noise ordinance issues. We can work on projects in design to prevent these issues or help you solve existing problems. Read on to learn how we helped our clients on a couple of projects.

The new TV broadcast studio at the Annenberg Public Policy Center at the University of Pennsylvania is an excellent example of how our design process can optimize the studio experience. Construction on the APPC building, designed by Fumihiko Maki, was completed in 2009, but the space reserved for the studio hadn’t been finished. When we first visited the studio, it was surrounded by a single stud wall with gypsum board on the outside only, the concrete slab was recessed, and there was no ceiling. The trolley passing by on the street was audible in the room and there was concern this would be picked up by microphones.

Photo Credit: Target Building Construction

To address this, room within a room construction was used. A floating floor filled in the existing recess and interior stud walls with multiple layers of gypsum board were built on top of the floating floor. A gypsum board ceiling was suspended from the deck with spring isolation hangers. Given the rectangular shape of the studio, we devised a layout for acoustic panels to reduce the reverberation time and ensure that no hard surfaces were directly across from each other. Final testing revealed a ¼ second reverberation time and no discernible echoes could be heard in the room. Additionally, the trolley was inaudible.


Photo Credit: Target Building Construction

We were also involved with the mechanical system design. Duct lining, low airflow, and low noise diffusers were used to achieve a maximum background sound level of NC-18. To minimize the sound from equipment racks in the control room, they were enclosed with a custom glass storefront system. This allowed for good isolation while keeping the equipment accessible. The studio opened successfully in the summer of 2011.

 Sometimes clients request our expertise to help solve existing problems. Recently, we received a call regarding a troublesome vibration running throughout a condominium building. The problem was so severe that elevator doors were rattling and ripples were visible in a bottle of water that had been left on a coffee table. An inspection of rooftop equipment revealed an improperly isolated exhaust fan. Although spring isolators had been installed, they hadn’t been set up properly and a wood beam was supporting the mid-section of the fan. This created a direct path for vibration transmission. Additionally, the existing ductwork was too small for the new fan. This caused turbulence which generated strong vibration that was transmitted into people’s homes through duct connections to the building. Due to the extensive runs of the old ductwork, the project team ultimately decided it would be less expensive to design a new exhaust system than replace the old duct. The system redesign is currently underway.

Similar Projects We’ve Participated In:

  • St. Joseph’s University – Lower Merion, PA
  • Dietz & Watson – Delanco, NJ
  • Penn Mutual Towers – Philadelphia, PA
  • Monmouth County Police Academy Outdoor Firing Range – Howell, NJ
  • McGuire Airforce Base
  • Blue Grass Plaza – Philadelphia, PA
  • Burlington Coat Factory – Edgewater Park, NJ
  • The Hershey Company – Hershey, PA
  • Lincoln Towers – Wilmington, DE
  • GlaxoSmithKline – Upper Darby, PA
  • Colorcon Global Headquarters and Technology Center – Harleysville, PA
  • Lundbeck Research USA – Paramus, NJ
  • SAP – Newtown Square, PA
  • PJM Interconnection – Norristown, PA
  • Pennsbury High School West – Fairless Hill, PA
  • Brackman Middle School – Barnegat, NJ
  • Club Quarters – Phildelphia, PA
  • Agilent Technologies – Newcastle, DE
  • Parc Rittenhouse – Philadelphia, PA
  • Garnet Valley High School – Glen Mills, PA
  • Kutztown University Schaeffer Auditorium – Kutztown, PA
  • Lockheed Martin – Moorestown, NJ
  • Masonic Village CCRC – Dallas, PA
March 2012: Cutting Edge
January 2012: Architecturally Integrated AV Systems