Acoustic Treatment For Quality Audio Recording At Home
Every single aspect of the room which you are using for audio recording, affects the quality of the audio. That's why acoustic treatment is important.
Usually, it can get tough to record studio-quality audio at home.
This is all because of the science of sound.
To record properly, you should be aware about the acoustics of your recording room.
Acoustics is a combination of science and art.
Therefore, to handle them well, you’ll have to keep a hold on both sections, especially science.
The physics of propagation of sound waves is very complicated.
Once you take into consideration the multitude of materials present in your house : floors, ceiling, and other equipment, you don’t know how the waves will travel in the room. And thus, acoustic treatment comes in handy.
Every single aspect of the room which you are using for audio recording, affects the quality of the audio. The room shape, size, wall-construction material, surface, items present in the room (furniture, equipment etc.) and many other things play a major role in the recording.
That’s why; it is difficult to talk about acoustic treatment for audio recording in just one guide, but we have to start at some point.
Why Do You Need Acoustic Treatment?
Normal rooms, i.e. untreated rooms have an uneven frequency response.
The recording will have the hallmarks of the space in which it is recorded.
The recording will be affected badly if you decide to record in your bedroom or living room.
If you want to make sure that the recordings are done like professionals, then you will have to pay attention to the acoustic properties of the environment.
The importance of room acoustics is highly underestimated.
It is not just the condenser microphone that will help you record great sounds, you will surely need great acoustics too.
Before you know how to employ the acoustic treatment for home studio, you need a brief understanding of acoustics in general.
The Science Behind Acoustics
When you create a sound in a room, it is projected in all directions simultaneously.
Some portion of the sound travels in a straight line towards the microphone.
The other sound waves hit the various surfaces and return (reflection).
Eventually, those waves hit the microphone thereby affecting the quality of the recording.
There are two reasons why these waves (the ones that don’t travel straight to the microphone) are undesired:
i) They enter the microphone a bit late, causing reverberation
ii) After hitting multiple surfaces, there tone and quality has been affected.
There are two methods to reduce/remove the undesirable sound waves: Absorption and Diffusion.
Absorption vs Diffusion
Absorption is the process of removing sound energy from the room.
An acoustic absorbent soaks up incident sound waves and reflects only a percentage of the incident sound waves.
Sound diffusion is the process of randomly scattering the sound waves all over the room.
In essence, diffusion does NOT remove sound from the room but it simply reflects them randomly in different directions creating a more naturally reverberating environment.
Whereas, absorption REMOVES all undesired sound waves from the room.
Which Method To Choose? Absorption or Diffusion?
Both these methods offer a different kind of effect: a combination of absorption and diffusion is the key to a good room sound.
Absorption makes the recording very dry. The recorded sound has no effects or coloration from the surrounding environment.
Diffusion gives it a lively sound. The recorded sound has the feeling of natural reverberation to it.
Keep in mind that if you’re recording at home, you wouldn’t (most probably) need diffusion. This is because the furniture (and other items) kept in your room would act as diffusers.
The method of diffusion is generally required in large empty rooms.
Use the following tips to decide what kind of acoustic treatment you require:
Vocals: If you’re planning to record only vocals then deploy as much absorption as possible. You want your vocals to be as dry as possible.
Instrumental recording: For instrument recording you want a good combination of absorption and diffusion. Assuming you already have diffusers in your room in the form of furniture, use light absorption for a good and lively recording.
If you’re recording in an empty empty room then diffusion is important to reduce the echo and reverb.
Which Room In Your House Should You Choose For Recording?
Ideally, the room in which you record should be fairly big.
To sound incredible, acoustics needs a very large space in which the reflected sound waves can travel but don’t interrupt the direct sound.
So the ideal room to record would be the largest room in your house.
Although, the balance in any recording studio is created by reflective surfaces, absorbent materials, and diffusive materials so you will have to treat your room with these materials.
What Do You Need For Acoustic Treatment?
To treat the sound of the room, you’ll need a few items:
- Pyramid or wedge acoustic panels
- Bass traps
- Wall diffusers
To absorb the high frequency sound, you’ll need wedge or pyramid acoustic foam panels.
These panels are made of special foam which is generally called acoustic foam. It attenuates the airborne sound waves and increases the air resistance to reduce the amplitude of the waves.
They are specifically used to control vibration, echoes, and noise level in the room.
Bass traps are used to absorb the low frequency sound. The low frequency waves (bass) always get amplified at the corners of a room. If you’re recording near a corner, bass traps are highly important.
Diffusers are used to scatter and diffuse the sound (duh!).
They cause interruption in the echoes created when the sound is reflected by walls and ceilings.
When the diffusers are used properly, they aid in retaining the positive acoustic qualities of the room.
You can purchase these items from MMT Acoustix here.
Where Should You Place The Acoustic panels, Diffusers and Bass Traps?
The placement of all panels depends on the type of treatment you want, here are a few guidelines to keep in mind:
- The ceiling should have sound absorbers as they can be useful to minimize the sound reflection which results in flutter echo or thinning the sound recordings.
- The side walls should use both absorbent and diffusive treatment to eliminate the comb filtering and echo as well.
- The wall at the back of the mic/instrument should have acoustic sound panels to prevent or effectively reduce the echo.
- The corners nearest to the mic/instrument should have a bass trap to reduce the bass build up
- Bass traps should also be used in the corners of the ceiling if necessary.
- The floors should be hardwood material to provide life to the recordings.
Recording Techniques to Improve Sound Quality
The output is not only dependent on the surrounding environment but also on how you record the sounds.
Here are a few tips to help you record better:
- Keep your microphone close, i.e. 3 to 6 inches from the instrument you are playing.
- Use directional mics that reject the acoustics coming from other directions.
- Record only one instrument at a time instead of recording the entire audio at once.
- If you are recording as a group, try to record in a large room and keep the musicians at a certain distance from each other.
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