Today we are going to see, ‘Are acoustics important?’ The answer is Yes, it is. But there is more to it than just a Yes. Let us see in detail. Let us start with What is acoustics.
What is acoustics?
You might have come across the word, ‘Acoustics’, don’t you? Let us see what it is.
Acoustics is a branch of sound engineering which deals with the reduction of unwanted sound by physical means. It involves the stuffing of materials inside, outside, or on both sides of the room. Acoustics is done in a hall, auditorium, church, living room, theatre, media room, etc. to get a quality sound reproduction from the speakers. Acoustics improves the intelligibility of the sound in a room. You can enjoy your music much more in an acoustically treated room. Movies sound like never before.
Why is acoustics needed?
In a room or any room for that matter, there will be bad sound. The echoes, reverberations, peaks, and nulls are formed when a speaker is placed in that room. The ideal frequency response human wants to hear in terms of HiFi audio is a flat frequency response. It is impossible to achieve a good sound in an untreated room. Acoustics can balance out the odds and evens in a room and therefore giving you a great sound.
Can I get good sound quality without acoustics?
No, unless in an open space. Open space has perfect acoustics. There won’t be any reflection from the walls, floors, etc.. no sidewalls to bring in reverberation, chances of echo are less. Therefore, you will get a good sound without acoustics. But, the in-room response is different. Even with expensive speakers, it is hard to get a good sound out of them. Therefore, your $1000 speakers will sound like a $100 speaker. A room with a highly reflective surface like the glass, marble floor is the worst for acoustics. So, Can I get good sound quality without acoustics? The answer is NO. A big NO.
Types of acoustics
There are two main classifications of acoustics.
- Noise isolation or soundproofing
- Room treatment for better sound.
This is also called noise reduction. It is done to prevent external noise to come in. It is mostly done by sealing the room from the outdoor environment. Sometimes double-walled concrete is used to make two walls and two doors will be used to keep the noise at the bay. The space between the two walls is either left free or filled with sawdust or some other insulator of sound.
Room treatment is to solve the issues in the room. The room is treated with absorptive materials, reflective materials, and resonators to make the room ideal for sound recording or listening. There is a measurement of echoes and reverberations in the room. It is called as RT60. If the readings are well, within the spec, you’re good to go. We will revisit RT60 later in this article. Basically, room treatment is the modification that is done inside the room for a better acoustic performance of sound.
Absorption and diffusion
Absorption and diffusion are carried out to make the room acoustically better for recording or listening. It can be a stereo listening room or a home theatre room. Absorbers and diffusers are placed in certain places so that we get a good RT60 and a good flat response.
The diffuser is a kind of acoustic treatment material that scatters the sound waves. Resonance happens when there are two surface and sound bounce back and forth it. The resulting wave combines with the new wave and produces a resultant wave that has peaks and nulls. This can be corrected by absorption and diffusion. Diffusion is preferred as resonance is strong acoustical energy. Keeping a diffuser on one of the walls will scatter the energy in all directions and therefore weakening the sound pressure wave. This way the peaks and nulls can be reduced.
Absorbers are just opposite to the diffusers. They just absorb the sound and convert it into heat energy. Absorbers are the easiest way to perform room treatment. They can be applied to the wall, ceiling so that sound waves hitting those surface hits the absorption panels and doesn’t return back. This way the reflections and echos are controlled for a better experience inside the hall.
Acoustic panels are panels made from sound-absorbing materials. The common material used in this case is corning’s Owens 703. It strikes a perfect balance between absorption of low frequencies and reflection of high frequencies. These can be made easily and is also available to purchase online. If corning Owens 703 is unavailable or has a threat as a health hazard, you can use rock wool for the same place as the Owens 703. Rockwool is relatively cheaper and has fewer health hazards. Make sure you wear a mask and gloves while working with it.
Bass traps are as the name suggests made to trap the bass. Bass traps are made with the same materials to build acoustic panels. The difference is that bass traps are thicker. This is because the bass frequencies are longer in wavelength and have higher energies. Only if the bass trap is thick enough, it can trap the bass. Else, it will fail. You can even use the normal acoustic panels as a bass trap in the corners of the room. The air gap between the panel and the wall will act as a trap and cut down low frequencies. This prevents boomy sound and gives rich, tight bass.
Foam acoustic panels
You might have come across these beautiful foam acoustic panels. Sorry to say that they don’t perform very well. They may act as an absorber but the acoustic panels are any day better than the foams. Foams even though the density is higher, it simply cannot function as a great sound absorber. Hence, forget about the foams and get a proper acoustic panel so that your investments will make a significant difference.
It is a form of a resonator that can be used to cut down a problematic frequency. Basically, these are fitted inside the wall with the mouth pointing outwards. When a sound wave hits them, they resonate and let out a frequency, perhaps the natural frequency of the resonator. This resonant frequency cancels with the upcoming problematic frequencies and therefore giving you a better sound.
How to do basic acoustics?
Basic acoustics is just enough for your room to show a significant difference in sound. Basic acoustics is easy to install and they don’t cost you much money.
You should begin with installing carpets on the floor. This will cut down a lot of reflections. You should have at least two acoustic panels. Now, you would need help from your friend and a mirror. After the speakers are placed, you gotta sit in the listening position. Now ask your friend to place the mirror on your right sidewall. Ask him to move the mirror until you get to see the tweeter of the right speaker. Mark it. Put an acoustic panel on it. Repeat the same on the left side as well.
This way, the early reflections are cut and gives a reasonable degree of reduction of reverberating sound but only at the listening position. This will do most of the job. Now take an acoustic panel and place it on the front wall between the speakers. This will improve the imaging of the sound. The Center image will become much clear. Take two more acoustic panels and place them on the rear wall such that the left panel faces the left speakers and the right panel faces the right speaker. That’s it. Congratulations. Now you have a room which sounds way way better now than in the past. This is how basic acoustics is done. If you have boomy bass, place one panel on the corner of the room on all four corners. This will give incredible results.
We have seen what is acoustics, related terminologies, what are absorption and delusion and finally, we have seen how to do basic acoustics in your hall. Doing this will return you significant benefits and you don’t have to worry about the poor sound or poor recording quality. Acoustics are very important that many studios spend a ton of money on acoustics. These are the reasons why is acoustics important
Thanks for reading.
Related post: How to setup a stereo system?
Aju Vignesh Sathiaraj Padma is a mechanical and audio engineer. He is a person who loves technology and things. He is also an audiophile and loves to listen to audio gears. He is an avid writer and loves to blog.
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