Acoustic Floor Treatments
Acoustic Soundproofing Panels – Don’t exsit!
Acoustic Soundproofing Panel is a name for an acoustic product which is often used but it is misleading and confuses two different types of acoustic solution.
An Acoustic panels is an acoustic treatment, which is the control of echoes and reverberation in a room typically trough absorption. Whereas soundproofing is about preventing sound from entering the space in the first place.
Therefore your will require;
- A solution to control the noise in the room such as an Acoustic Wall Panel, Acoustic Ceiling Panel or Acoustic Ceiling Baffle. The aim of these solutions is to reduce echo and reverberation
- A solution to stop noise entering the room in the first place such as a barrier mat such as TechMat or Tecsound. Soundproofing solutions often combine Barrier and absorption to achieve the result required. The aim is to block the noise and stop it in its path or at the very least reduce its energy (reduce the volume).
To ensure clarity and reduce confusion then let’s explore this a little further.
Have you ever heard of a friend who tried to soundproof his room by putting acoustic foam on the wall? Well, the attempt probably failed miserably because it is impossible to soundproof a room by just sticking any type of acoustic panels onto the wall.
What is acoustic treatment?
Acoustic treatment is the control of reverberations and echoes found in a space. I do not want to define acoustic treatment as “to reduce echoes and reverberation”, because even though most of the acoustic treatment jobs require the reduction of echoes and reverberation, some jobs require the redirecting of such echoes, such as in an opera house or a choral chamber. Nonetheless, let’s discuss how we can effectively reduce the reverberations and echoes in a room as that’s what most people want.
There are many types of acoustic panels for wall and ceilings made from many different types of materials and composites. But in scientific terms there are generally only 2 types of acoustic panels. There are acoustic panels that are soft to the touch such as fabric panels, foam panels, or polyester panels. Then there are acoustic panels which are hard to the touch, such as timber grooved panels, perforated metal panels, or even acoustic plaster. The general rule of thumb is that soft acoustic panels have better NRC (Noise Reduction Coefficient) than hard acoustic panels, and if you want the most bang for your buck, choosing the soft type is the way to go.
Many different rooms have different requirements of how little echo it should have. A measurement of the amount of echo found in a room can be ascertained with a test called the RT60 test. Basically the RT60 measures the amount of echo by seeing how long an impulse sound would take to decay by 60 decibels. An impulse sound is just an acoustician’s way of saying a loud sound.
Usually small rooms require a lower RT60 time and larger venues like an auditorium will not require as low an RT60 time as say, a smaller room like your bedroom. The amount of RT60 required also depends on what the venue is used for. For instance, vocal recording studio would require a very low RT60 time of 0.2 – 0.4 seconds, whereas a teleconference room would suffice with an RT60 time of 0.8 seconds.
Putting more acoustic panels in the room will reduce the RT60 time as there are more surfaces for absorption. A good estimate install enough acoustic panels to cover 60% of the exposed walls. This should allow you to reduce the echoes in the room and achieve a respectable RT60 time of 0.8 to 1.2 seconds, assuming it is a small to medium-sized room of about 500 – 1,000 sqft.
Now for Soundproofing or sometimes called “sound isolation” is very much different from acoustical treatment.
It is much harder to soundproof a room than it is to acoustically treat a room. We will discuss the different elements required for a soundproof room to work and the things to look out for.
A typical soundproof isolator
To begin, we will first understand the 2 ways the sound can travel.
- Air: It is of no surprise that sound can travel by air as a medium. This is the way we communicate with one another as the sound waves generated by our voice box is carried through the air and into the ears of our recipient. To prevent sound from travelling through the air from one space to the next, a sound absorbing substrate such as rockwool or Firetech foam can be used. The sound energy is converted into heat energy when it is trapped in the porous surface of the insulation material.
- Solid (structure): What is not commonly understood is that sound can travel by a solid structure too. This is commonly known as vibrations. Low frequency sounds are more like to travel through a solid structure such as a beam or soffit than mid or high frequency sounds are. To prevent the transmission of these low-frequency sounds, we need to decouple the structure. There are many ways to decouple the structure, but commonly used products include high-density barrer mats such as TechMat or Tecsound sound also isolators, resilient channels, and springs.
To fully soundproof a room, we need to build a room within a room (RWAR). A room within a room construction consists of building a smaller room in a larger room, and decoupling the smaller room from the larger room with isolators for the inner walls, joist isolators for the inner floor, and springs for the inner ceiling.
It is also important to consider the use of building materials with heavy mass, as these high-density materials will help to convert some of the low-frequency (LF) sound energy into heat energy before the transmitting through any isolators or springs.
This means the walls and ceiling of the inner room can be lined with lead-sheet or mass-loaded vinyls such as TechMat for maximum LF absorption. In between the inner room and outer room, a high-density packing of insulation of 80 – 100kg/m3 should be installed.
To prevent any possible short-circuiting of sound within the inner walls, floor, and ceiling, a neoprene rubber strip or foam tape strip should be used where the boards of the wall/ceiling/floor touches one another, along with a generous caulk of acoustic sealant to seal up any possible joint leaks.
This is obviously an extreme example but be aware soundproofing is not an easy job.
Hopefully this article will help ensure that you purchase the correct solution in the first place and you don’t waste money and time. But please give us a call if all this is a clear as mud or you need any help.