Building Acoustics and Acoustic Lighting

Architectural Acoustics and Acoustic Lighting

Often spaces where many people congregate can get quite loud. Reverberations of human voices can become intensified when a space isn’t treated properly for sound – creating a situation where people need to speak louder to be heard by the person to whom they are talking. This only increases noise levels which ultimately leads to an unpleasant and stressful environment. This problem can be mitigated by incorporating acoustic materials and acoustic lighting into your space.

Definitions and Terms for Building Acoustics and Acoustic Lighting

Absorption Coefficient – How much sound energy a surface absorbs at a specific frequency. For example, if a surface absorbed 25% of the energy and reflected 75% of the energy the sound at 500Hz, it would have an absorption coefficient of 0.25 at 500Hz.

NRC (Noise Reduction Coefficient) – The average of a surface's absorption coefficients at 250Hz, 500Hz, 1000Hz, and 2000Hz which generally covers the range of human speech.

RT60 (Reverberation Time, -60dB) – Within a space, the time it takes for a sound to "die-off" to the point that it is barely audible. This is equivalent to 60dB (decibels) of attenuation.

Equivalent Absorption Area – The area of an equivalent surface made of perfectly sound-absorbing material. For example, a 10' by 10' surface with an NRC = 0.50 would have a real area of 100 square feet, but an equivalent absorption area of 50 square feet (also known as imperial sabins).

Reverberant Noise Reduction (NR) – Decrease in the level of background (reverberant) noise in a space after adding acoustically-active objects. For reference, 1dB reduction is barely noticeable, 3dB is noticeable, and 6dB or more is very noticeable.

Understanding Building Acoustics and Sound Absorption

To understand how our acoustic pendant light fixtures can better absorb excessive noise, it is important to know about the Noise Reduction Coefficient, also known as NRC. This value measures how much sound a surface absorbs across the range of typical human speech at 250Hz, 500Hz, 1000Hz, and 2000Hz. This value is measured in sabins, which is the equivalent surface area of an object if it were made of 100 percent sound-absorbent material. In mathematical terms, sabins = the real area of the surface X the Noise Reduction Coefficient of the surface material. This calculation is crucial when considering the acoustics of any given space; an object with a greater sabins value will be more effective at attenuating reverberant noise than one with a smaller value.

The Visa Lighting Celest family of pendant lighting offers between 5.4 to 21.7 imperial sabins (in square feet) depending on the model chosen. Ultimately, installing multiple sound absorbing light fixtures will decrease the reverberation time of a space,  creating a quieter and more peaceful environment.

How to Calculate Room Acoustics

The Visa Lighting Acoustics Calculator provides a quick overview of the acoustics in a room. Simply enter in the room data – including measurements and materials – then select the acoustic light fixture you would like to incorporate.

The acoustics calculator uses Sabine’s formula to generate the -60dB reverberation time of your space before and after adding in acoustic lighting. Use this tool to play around with different fixture options and quantities to see what works best to help you reach your goal.