The greatest challenge to building a room, or booth, suitable for recording quality audio is ambient noise. Simple walls and basic building materials are definitely not suitable for dampening the various sounds and frequencies that surround us. To solve this issue, walls were built with two by four construction overlayed with dense compressed wood. Inside the walls is standard insulation along with a specialized sound dampening board that looks like compressed dead grass and dirt.
Most of the wall studs and floor joists are offset instead of straight across to help capture various sound frequencies. My research indicated that the more consistently shaped the air spaces in the wall and floor, the easier it is for various frequencies to penetrate into the sound room.
The floor is elevated two inches off the office floor by commercial casters. This helps isolate the floor of the “studio” from the low end frequencies and vibrations that easily move through solids. Flooring is completely enclosed with the spaces filled with the same as the walls. A dense foam rubber gasket to further isolate the interior of the room from the exterior also isolates the top floor.
All cabling and wiring is also run with an offset. By this I mean that the entry location of any cabling or wiring is approximately 30 inches to the side, or below the location of the other end on the inside of the room. Any straight through access from the outside to the inside would allow sound to travel through the walls with very little if any dampening.
Ventilation is provided by an ultra-quiet bank of 12v fans. The fans are placed within a ventilation box that is composed of two sides. One side provides incoming air and the other provides a return. Within the box are randomly placed caches of baffling to quiet the sound of air movement within the ventilation box.
Lighting comes from a special fluorescent lighting fixture rated for extremely quiet operation. There is none of the typical buzz heard from standard fluorescent lights.
Flooring is simply low pile commercial carpeting over a six pound pad and stretched to keep it from bunching up.
Finally, the door is built with an outside layer that is about three quarters of an inch overlap similar to the way the walls are built. This helps eliminate sound penetration through any gaps along the sides of the door.
In the next blog, I will discuss the equipment used to create the audio recordings.
Posted Sunday, March 28th, 2010 at 1:44 pm by peterl
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