While recording in a studio or making film in a SAE green room, noise produces; some of this noisy sound smacks on a surface, some of it is absorbed, some of it is reflected and some of it is transmitted through the surface.
Dense surfaces, for the most part, cut off the sound well, but reflect sound back into the room. Sponged surfaces are tended to absorb them instead of cutting of the noise. For a perfect recording, the studio should be acoustically treated.
This is the best way to stop sound transmission through a building structure and to isolate the sound source from the structure before its chance of vibration. This arrangement is known as ‘Acoustic Arrangement’. The aim is to analyze the acoustic situation of the SAE green room and give the recommendation to improve the acoustic treatment of the room.
The most important goals of acoustic treatment, done in a SAE green room or in a recording studio are to prevent standing waves and acoustic interference from disturbing the frequency response of recording studios and listening rooms; to reduce modal ringing in small rooms and lower the reverb time in comparatively bigger studios/green rooms; to absorb or diffuse sound in the room to avoid ringing and tremble echoes, and improve stereo imaging; and to keep sound from filtering through or out of a room.
This helps in prevention of the music from the disturbance of external source and keeping off the passing noise from getting into the microphones.
Basic Understanding of Acoustic System
In a recording studio or green room, its walls need to be isolated from ceilings and floors, usually by means of dense, pliable rubber. The chief ways to diminish sound diffusion from one space to another are adding mass and decoupling. Limp mass is generally better than rigid mass that is actually a combination of the two is really what you are after.
Every object, every construction material has a reverberating frequency at which it is virtually an open window to sound - kind of like a tuning fork that “sings” at its particular resonant frequency. Different materials have different reverberating frequencies.
Trapped air that is also known as air spaces works as a fabulous decoupler.
Airtight construction is a key concept. Like air and water, sound can also easily get through any small gap. It has a property of bouncing back and forth between hard, parallel surfaces.
It is important to understand that acoustic treatment is designed to control the sound quality within a room. It is not proposed to prevent sound proliferation between rooms. Sound transmission and leakage are reduced by construction. Thick massive walls and separated building structures are taken as intelligent acoustic construction tricks. This is generally done by floating the walls and floors, and hanging the ceilings with shock mounts.
By using proper acoustic treatment, a muddy sounding room with poor midrange definition and erratic bass response can be transformed into a great recording studio, having clear and tight sound that soothes ear. In absence of effective acoustic treatment, it is difficult to hear what is recording; it also make difficulties in production of good mix and sound notes.
A good acoustic system is important everywhere, even in a home theater, poor acoustics can make the sound less clear, harder to localize, and with an uneven frequency response. Even if you spent many thousands of dollars on the most accurate loudspeakers and other equipment available, the frequency response you actually realize in an untreated room is likely to vary by 30 dB or even more.
Types of Acoustic Treatment
There are basically two types of acoustic treatment; these are respectively ‘absorbers’ and ‘diffusors’. Absorbers are also divided into two types- first one controls midrange and high frequency reflections while another controls bass trap. This is mainly for low frequencies. All types of treatment are usually required in a recording room; this makes the environment suitable for making mixing decisions and for serious listening.
Many studio owners and audiophiles install acoustic foam all over their walls, as an assumption it’s sufficient. After-all, when one will clap hands in a room treated with foam (or fiberglass, blankets, or egg crates), no echo reverb can be heard. But thin treatments do nothing to control low frequency reverb or reflections, and hand claps
won't reveal that. Basement studios and living rooms having walls made of brick or concrete are especially prone to this problem - the more rigid the walls, the more reflective they are at low frequencies. Indeed, simply building a new sheet rock wall a few inches inside an outer cement wall helps to reduce reflections at the lowest frequencies because a sheet rock wall that flexes also absorbs a little.