ACOUSTICS
Acoustics is the study and practice of design for sound. Sound acts similarly to light.
In a studio, we wish to control or mitigate how sound travels, where it goes, and where it arrives.
These are a few factors:
- Reflectivity
- Reverberation
- Absorption
- Diffusion
- Transmission
A smaller space will have faster reverberation, due to the distance of reflectivity affecting the distance of travel of the sound. The larger the room, the more delay there is in reverberations.
Reflection is an issue when there are parallel walls, or a floor parallel to a ceiling. Sound-absorptive material will reduce, but not eliminate the issue where there are parallel surfaces. Sound absorptive materials with pyramid-shaped projections for diffusion may also decrease reflectivity.
Sound Transmission Issues
Sound is transmitted through not only air and water, but also through solid materials including:
- Concrete
- Steel
- Wood
- Plastic
- Glass
All hard surfaces can be a source of reflectivity.
Some studios go so far as to isolate the concrete floor from the adjacent floor, either in construction or in retrofit.
Most studios prevent sound transmission for fans or air conditioning or heating equipment.
Sound can be transmitted from the floor to the walls of a studio and there are ways of preventing it or reducing it to where it is not a problem or a factor.
There are assemblies of walls, which reduce the sound transmission and they each have been tested for the effectiveness of sound transmission control and have STC ratings.
Much of my knowledge of acoustics came from Chips Davis and his construction details I used for the sound mixing room at NBC Burbank, where The Tonight Show was filmed. I drew those plans and details. Chips used a laser transit to set the walls within thousandths of an inch tolerances. You may not need that precision, but his was state-of-the-art.
Chips also did what has been called live-end-dead-end design. One side of the room absorbs sound and the other reflects it.
Booths for singing may also be designed with live-end-dead-end design. The live end is the glass facing an engineer, typically. The singer faces the glass. The glass is STC-rated dual or triple pane, or double dual and triple pane with an air space in between.
Your needs and your budget should dictate how far you want to go for acoustically effective recording and mixing spaces. The cost can range from hundreds of dollars to millions of dollars and all in between.
Baffles, screens, bass traps, and other retrofit items for acoustic improvement may also be used. The key is knowing where and how to place them.