Acoustics

**__Definitions:__**

__Speed:__ Is the distance traveled by a wave in unit time (m/s). __Frequency:__ Number of waves that pass a point per second (Hz). __Wavelength:__ Distance between matching points on the wave (m). __Longitudinal:__ Vibration parallel to direction of travel (Ex.: Sound waves). __Transverse:__ Vibration at right angle to direction of travel (Ex.: Light and radio waves). 

__**Video:**__

__Vibration and impulsive sources:__ Sound is normally caused by objects vibrating. Larger objets make waves which create lower frecuency or lower pitch. Smaller objetcs create more wavelenghts and, therefore, higher pitch. __Acceleration noise:__ It is created by compression waves, for example, when the objects hit the ground.


 * __Some concepts:__**

__Reverberance:__ Is linked to the speed at which sound energy disappears in a room. __What are room acoustics?:__ Room acoustics are about the way in which sound behaves in a room. Sound transmission, sound absorption, sound reflection and sound diffusion are all aspects that are important here. Room acoustics also include how we as humans perceive different acoustic phenomena. The field of building acoustics covers sound insulation too, where the route that the sound takes from the room to other areas is included. __Room Acoustic Comfort:__ A room and its acoustic quality should be a support for people and the activities in which they are involved. To create the correct acoustic conditions is to create Room Acoustic Comfort™. Room acoustic comfort is an important element of the sound environment concept and this, along with light, air and perception of the room, is in turn a natural component of the total indoor environment. __What do you as an architect need to consider regarding Room Acoustic Comfort™?__ In many environments where people are present and communicate, high sound levels are perceived as one of the most disturbing factors. It is important to consider other descriptors that are directly linked to sound levels: the reverberation time, the sound level and the clarity of speech. __What must you as an architect do to achieve Room Acoustic Comfort™?__ In many of the commonly occurring types of rooms that we talk about here, a sound-absorbing ceiling is a practical aid for achieving Room Acoustic Comfort™ (RAC™). The ceiling’s sound-absorbing properties are described in sound absorption classes (A-E) in an international standard. Class A is the highest level of sound absorption.

**__Interview:__**

In the interview about noise and sound, Prof. Murray Hodgson explains how noise, signal and reverberation affect the acoustics of the architectural space. The interview is taking place in a restaurant because, according to Hodgson, a noisy place is not always a bad place. He says that, in a restaurant, the noise gives you an exciting feeling and it covers up other conversations. He also says that "signal" is a sound that is pleasant for you to hear it, and noise is the unwanted sound, but without it we would be able to overhear other conversations. At the end, he tells us how bad can be the noise for our health. Excessive noise can cause deaf, stress, fatigue, can make you feel unconfortable and it can reduce your quality of life.