To understand how sound panels work, start with the basic understanding of perceived noise. When an original sound is produced, such as the bark of a dog, there will be two distinct sound signals generated. The first sound wave will be the original sound of the bark of the dog, traveling along at a speed of 768 miles an hour direct to your ear drum. The second sound wave will be the reflection of the sound wave that otherwise will first bounce a perimeter surface and then arrive at the doorstep of your ear drum. The first and second sound signals, the original sound and the reflected sound, happen so close to one another, that to our human brain, it registers as a single sound. Sound panels reduce the second signal, and therefore lower the overall exposure to noise in the room.
Spikes in decibel level exposure happen when the perimeter surfaces are harder and more reflective, which increases the level of echo in a room. To soften the noise levels inside a room, sound panels are used to capture those echoes and convert them out of the room, leaving behind the original sound and a smaller percentage of the echo. The key to producing premium sound values inside a space is to define the correct acoustic panel, target the correct panel depth, and ensure that you do not under treat the space. So sound panels work because they lower your exposure levels to echo, which in turn lowers your overall exposure level to noise.
Most restaurant settings are good examples for this phenomena. With all the hard, reflective surfaces a restaurant will have for design and cleanliness purposes, those surfaces are notorious for bouncing noise around the room. The level of background noise spikes to uncomfortable levels, as patrons are left straining to hold conversation over a tabletop or bar stool. We’ve all been in these types of super loud environments, and the next time you are, look around and you will notice no ceiling or wall mounted sound panels. The echoes have taken the room over, and the restaurant owner has opted not to curb the exposure levels with sound panels.
So how to do sound panels work?
Historically, sound panels were once made mostly of acoustic foam. Foam is a chemically based panel that is filled with millions of tiny pores. The panels are placed on perimeter wall or ceiling surfaces, where sound waves will enter into the panel. As the individual pores become exposed to the sound wave, the pores will begin to vibrate. One molecule at a time, as the sound wave energy is passed through the panel, the vibration of the pores converts the sound wave energy to kinetic energy, which is a form of low grade heat. The heat will dissipate unnoticed out of the room, as the sound wave weakens. Only a small percentage of the original sound wave will therefore penetrate into and then back out of the foam panel. By the time that sound wave reflects back into the room, up to 80% of the energy is caught and converted. With only 20% of the sound wave remaining, the decibel level exposure in the room has dropped. The room sounds great because the echoes are under control.
Foam vs Fiberglass
Over time, the acoustic foam sound panel market began to advance its product, creating the panels out of melamine foam rather than polyurethane foam. The difference is in the fire rating. Any sound panel cut from melamine foam is class A fire rated and approved for use in any commercial venue. But any sound panel cut from polyurethane foam is class B and should never be placed in a school, a church, a restaurant, a hospital or other public buildings. With the advent of the melamine foam version of the sound panel, however, came a jump in price.
With either foam version of an acoustic sound panel, the market began to recognize that foam is actually a chemically based product that over time will begin to decay. After a span of about 7 years, acoustic foam will begin to crumble, flake and decompose. As this happens, the pores of the foam will age and be less effective at converting sound wave energy to kinetic energy. The panels will stop working as effectively as they did when first installed.
As a result of the need for longevity, durability, competitive pricing and a class A fire rating, the soundproofing market began to see a shift away from acoustic foam and towards fiberglass. Fiberglass panels do not deteriorate, they convert sound waves just as effectively as acoustic foam, the are class A fire rated, and will typically match or beat the unit price of a melamine foam panel. In today’s market, this is why fiberglass has replaced foam as the staple raw material from which today’s sound panels are made.
The next time you find yourself in a loud commercial space with poor room acoustics, look around and notice the absence of any cloth wrapped acoustic sound panel system flush mounted to perimeter wall or ceiling surfaces. The reflections of the sound waves are spiking noise levels and blurring sound signals, raising crowd noise and lowering intelligibility to speech. Conversely, the next time you find yourself able to sustain conversation in a restaurant or social setting, look around again, and you will notice panels on perimeter wall or ceiling surfaces that stay disguised in their presentation to the space, but serve to reward you with premium sound quality. So how do sound panels work? They simply get rid of the echoes and generate greater clarity to original sound.