Assignment 5: acoustic research

Given the number of projects that require special attention to sound control from concert halls to offices, plus the fact that conventional construction of floors, walls, and ceilings is often inadequate for controlling unwanted sound, design professionals benefit from knowledge of the principles of sound, plus methods for its control.
here are some basic facts about acoustics that i have picked up through the years.

Sound travels in waves. In solid building materials, it progresses as vibration. Building materials, such as stud walls, glass windows and concrete floors vibrate at a variety of frequencies when excited by sound or vibration. What we hear are fluctuations in air pressure produced by the vibrating surfaces.The application of acoustical finish materials or the design of a floor/ceiling assembly will depend on the frequencies needing to be controlled.

The application of acoustical finish materials or the design of a floor/ceiling assembly will depend on the frequencies needing to be controlled.

Low frequency (longer) sound waves are difficult to control with standard building materials.

Sound reflection in a room can be compared to light reflection. Light reflects most brightly from light colored or mirrored finishes. Sound reflects with little energy loss from hard surfaces like concrete or gypsum board. A soft surface such as carpet or curtains (dark surfaces for light) will not reflect as much sound.

Noise Reduction Coefficient (NRC) represents sound energy absorbed.

Absorption Coefficient (α) describes ability of material to absorb sound.

tradition acoustic wall paneling With its variety of shaped edges and panel thicknesses, the traditional acoustical wall panel offers design versatility and a solution for controlling reverberant noise while also controlling sound reflections in the room. Fiberglass core acoustical panels faced in fabric or vinyl can be placed on the walls or ceiling. Typically they are fabricated from 6-7 PCF fiberglass board with edges chemically hardened for durability. Maximum panel sizes are typically 4 ft. x 10 ft. Angled or contoured perimeter cut custom shapes can be specified. A 2 in. thick panel typically has an NRC value of 1.00

Reflective design in an auditorium or lecture hall. Ceiling and wall shaping directs sound to mid and rear seating areas.

Curved acoustical reflectors direct and diffuse sound to the seating area of the auditorium.

In a diffuse sound field sound level is uniform in all locations and from all directions.

Specular sound reflections off of flat wall and ceiling surfaces often produce inconsistent poor acoustic quality throughout the listening space;

 Strategies for controlling in-room noise include surface finish treatments such as acoustical panels that reflect, absorb and diffuse sound for a range of applications such as concert halls, swimming pools and auditoriums. Wall, floor and ceiling architectural framing designs that incorporate sound isolation products play a major role in controlling sound between rooms.