Introduction
Did you know that there was a study on whether egg cartons are good as acoustic panels? Yes! I mean No! Egg cartons are NOT good as acoustic panels, and yes, that has been proven in multiple studies!
We at Consonance Acoustics know a lot about acoustic panels because we have invented one!
This blog is about what exactly acoustic panels are and how you can determine which ones to use so that you don’t fall like Humpty Dumpty. Get it? Egg Joke? No? Anyways...
Why do you need acoustic panels?
Acoustic panels! Also known as sound absorbers, are panels used for absorbing sound. Why do you want to absorb sound? Because it reflects and causes chaos in the spaces where it reflects too much.
Acoustic panels stop the sound from reflecting back into the space. These panels are divided into three categories depending on the sound absorption mechanism they employ.
The first type is porous absorbers, the second is membrane absorbers, and the third is resonating absorbers.
If you are stuck on an acoustic design problem, we highly recommend that you simply send us a WhatsApp message at +917722005779 and tell us about the problem. We will help you find solutions that are catered to your specific requirements.
Porous Sound Absorbers
Let’s find out what porous absorber panels are -
All the absorbers that have pores in them, be it large or small fall into this category.
So, materials like drapes, carpets, glasswool, perforated ceiling panels, PET or felt panels etc. fall into this category.
The sound waves enter into these absorbers through these cavities, the air molecules near the surface and in these pores are forced to vibrate and the sound energy is dissipated in the form of heat.
Absorption of porous absorbers changes with frequency, thickness of the absorber, surface finish, how it is mounted etc.
For example, our high frequency acoustic panels become broadband acoustic panels when we introduce an air gap between the absorber and the walls.
You can find out how we have installed these panels in this video.
Porous absorbers will always absorb higher frequencies, with the introduction of an airgap or the increase in their overall thickness, they can extend their absorption in the lower frequency region.
Typical absorption coefficient graphs of porous absorbers look like this -
Membrane absorber panels
Moving on to Membrane absorber panels -
These absorbers are also known as vibrating panel absorbers. All the absorbers that have a non-rigid and non-porous membrane placed on an airgap are membrane absorbers. So thin sheets of MDF with an airspace behind or panels such as our patented low-frequency absorber panels fall into this category.
The sound waves exert pressure on the surface and the air gap behind it, which vibrate in a flexural mode that results in the absorption of sound. Absorption of membrane absorbers changes with the surface density, the airgap, and if any other material is present in that airgap (such as rockwool) which changes the impedance of the airgap.
Such absorbers can be called bass traps because their main function is to absorb only low frequencies. Membrane absorbers are used in places where you specifically want to absorb only the lower frequencies and avoid absorption in the higher frequency region.
Typical absorption coefficient graphs of membrane absorbers look like this -
You can check out our projects where we have implemented our patented low-frequency absorbers to get a feel of how they work.
Resonating absorber panel
Now the third kind of acoustic panel is the resonating absorber panel -
Resonating absorber panels absorb frequencies that resonate with the panel. I will tell you what it means. So resonating panels have an opening, a neck, and an air volume trapped in the cavity.
When sound waves interact with the surface, the air volume resonates in the panel at a given frequency which causes that frequency to get absorbed. Because of this mechanism, the range of absorbed frequencies is generally narrow in resonating absorber panels.
Wooden slats, sometimes perforated panels with an airgap behind them, Helmholtz resonators, and even earthen pots all act as resonating absorbers.
Absorption of resonating panels changes with the area of the opening, volume of the resonator, and length of the neck. Such kind of absorbers can be used to treat specific problem frequencies that arise in spaces such as studios and home theatres.
Typical absorption coefficient graphs of resonating absorber panels look like this -
Summary
So in summary,
Porous acoustic panels are for high-frequency absorption, Membrane acoustic panels are for low-frequency absorption, and resonating acoustic panels are for specific frequency absorption.
That brings us to the end of this article. To learn more about acoustics and such interesting facts, do subscribe to our blog, and don’t forget to share it with people who might be considering using egg cartons in their studios to stop them!
Comments