Background Information

This page will serve as a location to compile all information found to be useful and relevant to the project.  Ultimately this will include basic knowledge of sound, material interactions with sound, and impressive loudspeaker stand designs.

Sound

Sound travels through materials by causing a cascade of moving masses within this electrostatic bonding structure. The closer the molecular masses, and the more strongly bonded, the better and faster sound moves through something. It moves through steel very well, and quickly, at about 5000m / s, because iron atoms are packed close together and are well connected. Temperature affects the bonding, and sound obviously changes as state goes from solid, to liquid, and then to a gas. Ice sounds quite different from water. In carbon dioxide gas where the forces between distant molecules are relatively weak we find sound moves slowly at 259m / s. Of the 118 common elements, 63 are metals. That accounts for a wide range of physical properties, and more so if we allow alloys. Most metals are elastic, hard, dense, and acoustically very conductive.

Farnell, Andy. Designing Sound. Cambridge, MA, USA: MIT Press, 2010. ProQuest ebrary. Web. 7 April 2015.
Copyright © 2010. MIT Press. All rights reserved.

Sound Absorption

"The sound absorption coefficient indicates how much of the sound is absorbed in the actual material.  The absorption coefficient can be expressed as: a = Ia / Ii where Ia = sound intensity absorbed and Ii = incident sound intensity."

Reference: http://www.engineeringtoolbox.com/accoustic-sound-absorption-d_68.html

Loudspeaker Stands

In the 1970s, musicians found that by lifting speakers off the ground and mounting them on something that had no vibration would increase sound quality. It was discovered that ordinary furniture was not built with properties to deaden vibrations and enhance the speaker's sound. Loudspeaker stands were built to remove any harmful tones that came up through unwanted vibration. When more research was done, it was found that speakers are best positioned when the tweeter (type of speaker driver that produces the highest range frequency) is level with the ear of the listener. From that knowledge, loudspeaker stands are often built to have the speakers line up with the ear of a person when they are sitting down. 

Stiffness

"Stiffness is the ability of a material to maintain its shape when acted upon by a load."    In the case of a loud speaker stand, the stiffness of a material is important because a stiff material will reduce vibrations.  For this reason we chose to use steel and hardwood to build the loudspeaker stand.  

Charles, J. A., and F. A. A. Crane. "Stiffness." Selection and Use of Engineering Materials. London: Butterworths, 1989. N. pag. Print.