Acoustics

=**ACOUSTIC**=
 * Arquitecture**


 * SPEED**

//archaic// **:** prosperity in an undertaking **:** success 2 //a// **:** the act or state of moving swiftly **:** swiftness //b// **:** rate of motion: as //(1)// **:** velocity 1 //(2)// **:** the magnitude of a velocity irrespective of direction //c// **:** impetus 3 **:** swiftness or rate of performance or action **:** velocity 3a

The number of times that a periodic function repeats the same sequence of values during a unit variation of the independent variable
 * FREQUENCY**

The distance in the line of advance of a wave from any one point to the next point of corresponding phase
 * WAVELENGTH**

Placed or running lengthwise 2 **:** of or relating to length or the lengthwise dimension 3 **:** involving the repeated observation or examination of a set of subjects over time with respect to one or more study variables
 * LONGITUDINAL**

Made at right angles to the long axis of the body <a //transverse// section
 * TRANSVERSE**


 * VIDEO NOTE-TAKING**

Sound is the result of objects vibrating Small objects create small waves and higher frequencies. The source of a sound is not necesarily a result of the image we are perceiving, but of the acceleration noise.


 * ARTICLES NOTE-TAKING**

A room and its acoustic quality should be a support for people and the activity in which they are involved When a sound wave strikes one of the surfaces of a room, some of the sound energy is reflected back into the room and some penetrates the surface. Parts of the sound wave energy are absorbed by conversion to heat energy in the material, while the rest is transmitted through. The level of energy converted to heat energy depends on the sound absorbing properties of the material.

In some premises, conditions are such that a wall-to-wall sound-absorbing ceiling on its own is not sufficient to create good acoustics. New findings show that in, for example, day-care centres and schools for younger grades, it is not only important to reduce the reverberation time, but also to reduce the sound pressure level as a whole. This is best done by maximizing the amount of sound-absorbing material, meaning that the walls have to be used for sound absorption as well. Optimal conditions are achieved by distributing absorbers over other surfaces than just the ceiling.

These formulas, however, are designed for ideal conditions with **diffuse sound fields**. In reality, the sound field is far from diffuse. It will probably consist of two main parts: one grazing and one non-grazing.
 * Reverberation time (RT)** is by far the most frequently used parameter for calculations and measurements within room acoustics. The formulas used are normally the Sabine formula or some modified version of it. They are easy to use - you need the room volume and the amount of sound absorption, calculated with the absorption coefficient α p.

The use of free-hanging units provides flexibility and a multitude of acoustical solutions to problems related to acoustical design. Where free-hanging units are used to improve poor acoustics, solitary units give the benefit of diffraction effects, with a larger area of the absorbing patches being exposed to the sound field. Both effects can be used to increase sound absorbing properties.