Acoustics & Noise Control

Design Consultation

• Noise Isolation - We specify wall and floor construction to minimize air-borne and structure-borne noise transmission into sensitive spaces such as classrooms, multi-unit dwellings, offices, music rooms, recording studios, and theaters.
• Architectural Acoustics - We specify surface treatments and recommend room dimensions and shapes to control the quality of sound propagation in enclosed spaces. Any type of occupied space can benefit from good acoustics. Problems such as poor speech intelligibility, excessive occupant noise, and poor speech privacy are among the issues that can be corrected with proper selection and placement of sound absorbing materials. Furthermore, good sound diffusion and propagation in lecture halls, theaters, classrooms, and music rooms will result from appropriately placed reflective materials.
• Noise & Vibration Control - We specify sound attenuators, maximum air velocities, isolation of ducts, pipes, and equipment in order to meet appropriate levels of background noise and vibration in occupied spaces. We also provide consultation in space planning for HVAC equipment.
• Seismic Engineering

List of current and recent projects

On-site Measurements

• Noise Insulation - Field Sound Transmission Class (F-STC), Apparent Sound Transmission Class (A-STC), and Noise Isolation Class (NIC) are among the ratings that can be measured for installed wall partitions and floor/ceiling assemblies. The F-STC rating most closely compares to the laboratory rating of Sound Transmission Class (STC). The A-STC rating includes the effect of flanking paths, such as open-plenum ceilings, doorways, etc. The NIC rating represents the raw sound level drop across the partition, and does not make the corrections for the measurement environment that the F-STC and A-STC ratings do. We perform all of the above tests according to the most recent ASTM standards E336 and E413.
• Impact Insulation - Field Impact Insulation Class (F-IIC) rates the effect of footfall noise, and is performed with the use of a standardized tapping machine that conforms to ISO standard 140/6. The tapping machine is placed on the floor of a floor/ceiling assembly while the sound levels are measured in the space below. Corrections are made for the room acoustics in order to achieve a result that closely compares with the laboratory rating of Impact Insulation Class (IIC). We perform this test according to the most recent ASTM standards E1007 and E989.
• Reverberation Time - This is the measurement of the time for sound to decay 60 dB. Reverberation time is directly related to the sound absorption present in a space, and is utilized when improving room acoustics and background noise levels.
• Mechanical Noise - Using integrating/averaging instruments, we measure background HVAC-related noise levels, environmental noise levels, and report several metrics, including the commonly specified Noise Criteria (NC), Room Criteria (RC), and dBA.

We use the following instruments to support the above measurements:

• Norsonic N118 Type-1 (Precision) Sound Level Meter/Realtime Analyzer
• DI-2200 Realtime FFT Analyzers, 2-channel
• HP 3560A Dynamic Signal Analyzer, 2-channel
• Cesva MI005 Tapping Machine
• Genrad Type 1 and 2 Sound Level Meters and Analyzers
• Genrad 1562-A Sound Level Calibrator
• CEL 284/2 Acoustical Calibrator
• Genrad 1390-B Random Noise Generator
• Ivie IE-20B Noise Generator
• Peavy 300 Series Monitor, Equalizer/Power Amplifier
• Peavy 112DL Loudspeaker
• Wilcoxon General Purpose Accelerometers
• PCB General Purpose Accelerometers
• PCB 393C Seismic Accelerometer
• Wilcoxon 731 Seismic Accelerometers 10 v/g