Acoustic

=Acoustic=

====Speed: is the rate of motion, or equivalently the rate of change of distance. Speed is a scalar quantity with dimensions length/time; the equivalent vector quantity to speed is velocity. Speed is measured in the same physical units of measurement as velocity, but does not contain the element of direction that velocity has. Speed is thus the magnitude component of velocity.==== = =

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= = ====Frequency: is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency. The periodcycle in a repeating event, so the period is the reciprocal of the frequency. is the duration of one==== = =

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= = ====Wavelength: is the distance between repeating units of a propagating wave of a given frequency. Wavelength is therefore inversely proportional to frequency. Waves with higher frequencies have shorter wavelengths. Lower frequencies have longer wavelengths, assuming the speed of the wave is the same.==== = =

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[[image:http://upload.wikimedia.org/wikipedia/en/thumb/1/1a/Wavelength.svg/320px-Wavelength.svg.png align="center"]]
====Longitudinal waves: are waves that have same direction of oscillations or vibrations along or parallel to their direction of travel, which means that the oscillations of the medium (particle) is in the same direction or opposite direction as the motion of the wave. Mechanical longitudinal waves have been also referred to as compressional waves or compression waves.==== = =

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= = ====Transverse wave is a moving wave that consists of oscillations occurring perpendicular to the direction of energy transfer. If a transverse wave is moving in the positive //x//-direction, its oscillations are in up and down directions that lie in the //y-z// plane.==== =

Reverberance is linked to the speed at which sound energy disappears in a room. An unfurnished room with hard surfaces, such as a church, is perceived as being more reverberant than a well-furnished living room.

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.

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

**The reverberation time is decided by:** - Added absorption and how it is placed - The quantity and placing of sound-scattering objects such as furniture, shelves etc. - The size and shape of the room **The sound level is essentially determined by:** - The amount of absorption **Clarity of speech is essentially determined by:** - Early sound reflections in relation to late sound reflections - Background noise

Give priority to the different acoustic properties such as reverberance, speech clarity and sound level, depending on what the room is used for. For example:
 * Sound level reduction will be most important in a kindergarten.
 * In a music room, the response of the room in the form of reverberance can be the most important aspect.
 * In a teaching situation, it is important to give priority both to speech clarity and to reduction of sound level.
 * In an open office landscape, it is essential that the sound propagation is restricted in order to minimise disturbance, mainly between different work groups. It is important that the sound level falls quickly with distance.


 * 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
 * Effective, sound-absorbing ceilings (Sound absorption class A) affect reverberation time, sound level, speech clarity and spatial decay, thus creating good room acoustic comfort