Acoustics




 * **Speed**: It**' ** s the scalar quantity which is the magnitude of the velocity vector. The SI units for speed are **m / s ** (meters per second).


 * **Frequency:** The number of times a specified phenomenon occurs periodicly in a specified interval. In physics is the number of times that a periodic function or vibration repeats itself in a specified time. It is usually measured in hertz. Symbol  **ν**, **//f.//**


 * **Wavelength:** Is the distance, measured in the direction of propagation, between two points of the same phase in consecutive cycles of a wave. Symbol  **λ**


 *  **Longitudinal**: Means along the length, running lengthwise, or (by extension) over the course of time. Sound is transmitted through gases, plasma, and liquids as longitudinal waves, also called compression waves. And these longitudinal waves are waves that have the 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.
 * **Transverse:**    Crossing from side to side; athwart; crossways. A 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.



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VIDEO: The Sound Sources (Salford's amazing world of sounds).**__

The video explains what'sl the sound and where it comes from, how is it produced and the different ways to get it.

Sound is caused by the vibration of objects. Big objects make large waves and lower frequency notes. Small objects on the other hand create small waves and there for higher frequency notes. If we blow something like a balloon, as we make it bigger, it goes more and more transparent, it’s because the rubber of the balloon has to spread on a bigger area, the same thing happens with the energy of sound, it has to spread over a bigger area, and there for it has to get quitter because the energy is smaller.


 * Sources of impulsive sound: When we clap, we can actually see our hands vibrate, but what we hear is he acceleration noise. When we bring our hands together, we force the air out from between our hands and it creates a compression wave, which is an acoustic wave that’s what we hear. If we clap our hands in different ways we get different noises.

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INTERVIEW TO PROFESOR MURRAY.**__

He defines the phenomenon of sound as noise, telling us that it exists what it denominated a “signal”, that talks about the useful sound, raising a difference between useful sound and noise that is equivalent to wanted sound. Respecting to the sound while we're designing, he comments that a building is a physical system that has an requirement into the emotional sense for humans that create a movement, depending on the quality of the music. He made reference that the amount of noise in a place depends on the activity that is developed there, of the privacy that is desired to obtain, to differentiate the public zones and the consequences that the sound in the space can bring. The acoustics in the theaters depends as much on the priorities of the person as of the objectives that are desired to fulfill in the place.