BUILDING UTILITIES 3 Module 1 Lecture 4 ROOM ACOUSTICS EXAM QUESTIONS AND ANSWERS

BUILDING UTILITIES 3 Module 1 Lecture 4 ROOM ACOUSTICS EXAM QUESTIONS AND ANSWERS ROOM acoustics - answerdeals with sound in lecture or concert halls, meeting rooms and classrooms. −The character of the room greatly affects sound production, assisted by loudspeakers or not. Suitability - answeris determined by the correct choice and placement of sound-absorbing and sound-reflecting materials in a room (reverberance) and the prevailing (background) noise level in it. reflectors, sound-absorbing - answer−Properly placed _____________can direct the sound to where it will do most good. Properly placed __________materials will prevent reflections that might cause unpleasant echoes or cause sounds to interfere and cancel each other out. too reverberant - answer−In rooms that are __________, it is difficult to understand speech; In rooms that are not reverberant enough, music will sound dead and lifeless. 100 Hz - answer−The liveliness of a room is described by its reverberation times which vary with frequency; reverberation time is usually longer at frequencies around _________ than it is around 5000 Hz. 2 , 0.5 - answer−In concert halls, the average reverberation time is around ________seconds. In homes, it is around ___seconds. -Sound pressure - answerRelated to the amount of energy it carries -Sound power - answerProperty of the source -Sound intensity - answerFlow of power through a specific area -Sound pressure level -Sound power level -Sound intensity level - answer§Absolute measures §Sound pressure or amplitude - answeris caused by the acoustic power output of a sound source but is influenced by the nature of the environment between the source and the receiver; sound pressure is an environment-source property greater - answerSounds with ___________amplitude will produce greater changes in atmospheric pressure - from low pressure to high pressure woodwind player - answerA __________ may increase the amplitude of their sound by blowing harder. §Amplitude - answeris measured in the amount of force applied over an area. The most common unit of measurement of force applied to an area for acoustic study is the Newtons per square meter (N/m2). Sound power - answeris an independent property of a sound source that quantifies the source's acoustical output §It is constant for any given source operating under defined conditions and is not influenced by the nature of the surroundings into which a source is placed §If we picture a sound wave as an expanding sphere of energy, power is the total amount of kinetic energy contained on the sphere's surface; power is a measurement of amplitude over time. oThe unit of measurement for power is the watt, named after James Watt.1 watt = 1 Newton of work per second intensity. - answer§The power of the original sound source along with distance of measurement from the sound source combine to form the ___________ §As the surface area of the sound sphere expands, the amount of energy generated by the sound source is distributed over an exponentially increasing surface area. watts per square meter or w/m2 - answer§Intensity can be measured as ___________. Intensity can be seen as amplitude over time over an area. inverse square law, - answer§The amount of energy in any given square meter of the expanding sphere's surface decreases exponentially by the ______________, which states that