Acoustics

Here are some important definitions and questions related to acoustics: [[image:opera2.jpg width="427" height="398" align="right"]]
**Speed:** Distance travelled in unit time (m/s) **Concepts learned from the video sound sources-high speed film: ** =Speed of sound: is the speed at which sound travels in a given medium under specified conditions. =
 * Frequency:** Is the number of complete waves that pass a point per second, frequency is also named pitch and is measured in Hertz (Hz)
 * Wavelength:** Distance between matching points on the wave (m), there are short wavelength and long wavelength.
 * Waves:** Carry energy from one place to another, sound, light and radio signals all travel in the form of waves, there are two main types of wave: transverse and longitudinal.
 * Transverse:** Vibration at right angle to direction of travel, light and radio waves are transverse waves.
 * Longitudinal:** Vibration parallel to direction of travel, sound waves are longitudinal. 
 * Vibration:** The act of vibrating, or the state of being vibrated, or in vibratory motion; quick motion to and fro; oscillation, as of a pendulum or musical string.
 * Sound:** Sound is energy transmitted through the movement of air molecules. When sound travels it is a pressure wave compressing the air then the air decompresses as the sound travels.
 * Sonic booms:** An explosive sound caused by the shock wave preceding an aircraft traveling at or above the speed of sound.

 **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. High noise levels have a negative effect on us and affect health, communication, safety, economy (effectiveness/productivity), learning and general wellbeing.  As architects we need to consider the next acoustic descriptors regarding Room Acoustic Comfort™ > - Added absorption and where it is placed, > - The quantity and placing of sound-scattering objects such as furniture, shelves etc. > - The size and shape of the room > - Early sound reflections in relation to late sound reflections > - Background noise  **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™. 
 * Another concepts or ideas: ** <span style="color: #008000; font-family: Arial,Helvetica,sans-serif; font-size: 99%;">**Reverberation:** The reverberation time is defined as the time it takes for the sound level to decrease with 60 dB, short reverberation time means good acoustics. In most premises comfortable room acoustics depend directly on a short reverberation time. Rooms intende <span style="color: #008000; font-family: Arial,Helvetica,sans-serif;">d for conversation, or where a high degree of privacy is required, are most dependent on short reverberation times. In a room with a long reverberation time, one word does not have time to decay before the next reaches the listener, so the intelligibility of speech is poor.
 * Room acoustics:** describes how sound behaves in an enclosed space.
 * 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. The interaction between the person, the room and the activity decides the room acoustic comfort.
 * <span style="color: #008000; font-family: Arial,Helvetica,sans-serif; font-size: 109%;">In many environments where people are present and communicate, high sound levels are perceived as one of the most disturbing factors
 * <span style="color: #008000; font-family: Arial,Helvetica,sans-serif; font-size: 109%;">High noise levels have a negative effect on us
 * <span style="color: #008000; font-family: Arial,Helvetica,sans-serif; font-size: 109%;">The reverberation time is decided by:
 * <span style="color: #008000; font-family: Arial,Helvetica,sans-serif; font-size: 109%;">The sound level is essentially determined by the amount of absorption
 * <span style="color: #008000; font-family: Arial,Helvetica,sans-serif; font-size: 109%;">Clarity of speech is essentially determined by:
 * <span style="color: #008000; font-family: Arial,Helvetica,sans-serif; font-size: 109%;"><span style="color: #008000; font-family: Arial,Helvetica,sans-serif; font-size: 99%;"> The ceiling’s sound absorbing properties are described in sound absorption classes (A-E) in an international standard.
 * <span style="color: #008000; font-family: Arial,Helvetica,sans-serif; font-size: 109%;"><span style="color: #008000; font-family: Arial,Helvetica,sans-serif;">Class A is the highest level of sound absorption. <span style="font-family: Arial,Helvetica,sans-serif;">
 * <span style="color: #008000; font-family: Arial,Helvetica,sans-serif; font-size: 109%;">Effective, sound-absorbing ceilings (Sound absorption class A) affect reverberation time, sound level, speech clarity and spatial decay, thus creating good room acoustic comfort. <span style="color: #008000; font-family: Arial,Helvetica,sans-serif; font-size: 110%;">