Acoustics and Lighting Pre-midterm Quiz

Hertz is the correct answer because it is the unit of frequency. Frequency refers to the number of cycles or vibrations per second in a sound wave. Hertz is commonly used to measure the frequency of sound waves, as well as other types of waves such as radio waves and electromagnetic waves. Timbre, pitch, and tone are all characteristics of sound, but they are not units of frequency.

Environmental Acoustics deals with the effects of the environment on audible sound waves. It focuses on how sound waves interact with various elements in the environment such as buildings, landscapes, and atmospheric conditions. This field of study helps in understanding how sound travels, gets reflected or absorbed, and how it is affected by factors like temperature, humidity, and wind. It also involves studying the impact of human activities on the environment and how they contribute to noise pollution.

Sound transmission refers to the ability of sound waves to pass through a surface or material. When sound waves encounter a surface, they can either be reflected, absorbed, or transmitted. In the case of sound transmission, the waves are able to penetrate through the surface and continue propagating on the other side. This can occur when the surface is thin, porous, or not well-insulated. Sound transmission is an important factor to consider in various situations, such as in building construction or noise control, as it can impact the level of sound that is heard on either side of the surface.

The correct answer is "Threshold of Audibility." This refers to the minimum intensity of sound that can be detected by the ear, resulting in an auditory sensation. It is the point at which sound becomes just barely perceptible to the human ear.

The correct answer is "Threshold of Pain". The minimum sound pressure level that stimulates the ear to a point which is painful is referred to as the threshold of pain. This means that when the sound reaches a certain intensity, it becomes physically uncomfortable or even painful for the listener. It is an important concept in understanding the limits of human hearing and the potential harm that can be caused by excessive noise levels.

Sound travels through different mediums at different speeds. In this case, the correct answer is air because sound travels at approximately 344 meters per second through air. Water, wood, and steel are denser materials compared to air, and sound travels slower through them.

An amplifier is used to increase the magnitude of the electric signal received from the microphone. It boosts the signal strength so that it can be delivered to the loudspeakers. The amplifier may also include separate mixers, which allow for additional control and adjustment of the audio signal before it is sent to the loudspeakers.

Down lighting refers to a type of decorative accent lighting where the light is directed downwards, illuminating the area below. This type of lighting is commonly used to highlight specific objects or areas, create a sense of depth and dimension, and provide a soft and subtle ambiance. It is often used in residential and commercial settings to create a warm and inviting atmosphere.

Sound pressure refers to the variation in air pressure caused by a sound wave. When a sound is produced, it creates a disturbance in the air particles, causing them to vibrate. These vibrations create fluctuations in the atmospheric pressure, which can be measured as sound pressure. The amplitude of the sound wave determines the magnitude of the sound pressure, with higher amplitudes resulting in louder sounds. Therefore, sound pressure is a measure of the intensity or strength of a sound wave.

The most favorable reverberation time for a particular space and volume is referred to as the optimum RT. This means that the reverberation time in that space and volume is ideal for producing the desired acoustic characteristics. The optimum RT ensures that the sound reflections and decay in the space are balanced, resulting in clear and pleasant sound quality. It is important to consider the optimum RT when designing or evaluating the acoustics of a room or venue to achieve the desired sound experience.

Architectural acoustics is the correct answer because it specifically focuses on the science of sound phenomena in buildings. It involves studying how sound is produced, transmitted, and absorbed within a building environment. This field is concerned with creating optimal acoustic conditions in various architectural spaces, such as concert halls, theaters, and recording studios. By understanding architectural acoustics, architects and designers can ensure that sound quality and clarity are maximized, minimizing issues such as echoes, reverberation, and noise transmission.

Sound does not travel at a fixed speed at normal room temperature. The speed of sound depends on various factors such as the medium through which it is traveling, temperature, and humidity. In general, sound travels faster in solids and liquids compared to gases. At room temperature, the speed of sound in air is approximately 343 meters per second. Therefore, the given statement that sound travels at 360m/s at normal room temperature is false.

Wavelength refers to the distance a sound wave travels during each complete cycle of vibration. It is the physical distance between two consecutive points in a wave that are in phase, such as the distance between two consecutive peaks or two consecutive troughs. Wavelength is an important characteristic of a sound wave and is directly related to its frequency, as the wavelength decreases with an increase in frequency.

Amplitude refers to the strength or power of a wave signal. In the context of a graph, it represents the "height" of a wave. It is a measure of the maximum displacement of particles in the medium from their equilibrium position when a wave passes through. A higher amplitude indicates a more powerful or stronger wave signal, while a lower amplitude indicates a weaker signal.

Pitch refers to the perceived frequency of a sound. It is the attribute of an auditory system that allows us to distinguish between high and low frequencies. By perceiving pitch, we can pinpoint sounds on a scale extending from high to low frequencies. Hertz, timbre, and tone are related to sound but do not specifically refer to the ability to pinpoint sounds on a frequency scale.

A tone refers to a steady periodic sound that is produced by a vibrating object or instrument. It is characterized by its pitch, which is the sensation of highness or lowness of a sound. Timbre, on the other hand, refers to the quality or color of a sound, while Hertz is the unit used to measure frequency. Although all of these terms are related to sound, the best choice that fits the given description is "Tone."

Sonics is the correct answer because it refers to the study or science of sound, including the production, transmission, and effects of sound waves. It specifically deals with sounds at frequencies that are too high to be heard by humans, which aligns with the given explanation. Electro Acoustics focuses on the interaction between electrical signals and acoustic waves, Hertz is a unit of frequency measurement, and Psycho Acoustics deals with the psychological and physiological responses to sound.

Sound overlap refers to the phenomenon where multiple sound sources emit sound waves that overlap and interfere with each other in a given area. This can result in an amplified sound experience as the combined sound waves add up and create a louder effect. In areas where multiple speakers are present, such as in a concert hall or a crowded room, sound overlap can occur, leading to a more intense and immersive auditory experience.

Providing ceramic materials (e.g. tiles) on walls is not a way to diffuse sound because ceramic materials are typically hard and reflective, which means they tend to reflect sound rather than absorb or scatter it. Diffusing sound involves breaking up sound waves and scattering them in different directions to reduce echo and reverberation. Surface irregularities, alternating application of finishes, and random application of finishes can help achieve this by creating diffusive surfaces that scatter sound waves.

The statement is false because according to the law of reflectivity, the angle of incidence is always equal to the angle of reflection. This means that when a ray of light strikes a surface and reflects off it, the angle at which it hits the surface is always equal to the angle at which it bounces off.

Cove lighting refers to a type of decorative accent lighting that is installed along the upper perimeter of a room or on ledges and recesses. It is designed to provide indirect lighting, creating a soft and diffused glow that enhances the ambiance of a space. Cove lighting is often used to highlight architectural details, create a sense of depth, or add a touch of elegance to a room. It can be used in both residential and commercial settings and is a popular choice for creating a warm and inviting atmosphere.

Timbre refers to the quality or character of a sound that distinguishes it from other sounds of the same pitch and volume. It is determined by the combination of various factors such as the number, prominence, pitch, and intensity of the overtones present in a sound. In other words, timbre is what makes a sound unique and allows us to differentiate between different musical instruments or voices, even when they are playing or singing the same note at the same volume.

Landscape Acoustics is the correct answer because it refers to the study of sound in outdoor environments, specifically focusing on how sound interacts with the physical features of the landscape. This includes analyzing how sound is affected by natural elements such as terrain, vegetation, and water bodies, as well as man-made structures like buildings and roads. It also involves assessing the impact of sound on the overall aesthetic and quality of outdoor spaces.

Coffer lighting refers to a type of decorative accent that involves recessed or sunken panels in the ceiling, which are often illuminated to create a visually appealing effect. This type of lighting adds depth and dimension to a room by highlighting the architectural details of the ceiling. It is commonly used in high-end residential and commercial spaces to create a luxurious and sophisticated ambiance.

A microphone is a device that picks up sound energy from a source, such as a person speaking, and converts it into electric energy. This electric energy is then fed into an amplifier, which increases the power of the signal. The amplifier then sends the amplified signal to the loudspeakers or tweeters, which produce sound waves that can be heard by the audience. Therefore, the microphone is responsible for capturing the sound and converting it into a usable electric signal.

A subwoofer is a loudspeaker that is specifically designed to reproduce low-pitched audio frequencies, commonly known as bass. It is responsible for delivering deep and powerful bass sounds in audio systems. Unlike tweeters, which are designed for high-frequency sounds, subwoofers focus on the lower end of the audio spectrum. Coaxial units and megaphones are not dedicated to reproducing low-pitched audio frequencies like a subwoofer.

A sound shadow occurs when an area does not receive an adequate amount of direct sound. This means that the sound waves are blocked or absorbed by objects or obstacles in the environment, preventing them from reaching the area. As a result, the area experiences a lack of sound or a reduced volume compared to other areas. This phenomenon is commonly observed in spaces with uneven surfaces, corners, or barriers that obstruct the path of sound waves.

A whispering gallery is a term used to describe a space or structure where sound waves can travel along curved surfaces, such as a hemispherical dome or an elliptical enclosure. This phenomenon allows high frequency sounds to "creep" or propagate along these surfaces, creating a unique acoustic effect. The term "whispering gallery" is often used to refer to specific architectural structures, such as the Whispering Gallery in St. Paul's Cathedral in London, where whispered sounds can be heard clearly across the gallery due to the curved shape of the dome.

Loudness refers to the subjective attribute of an auditory sensation. It is the perception of the intensity or volume of a sound. It is a measure of how loud or soft a sound is perceived to be by an individual. The loudness of a sound is determined by the sound pressure level, which is the physical measurement of the intensity of sound waves. The threshold of audibility refers to the minimum sound pressure level that can be detected by the human ear, while the threshold of pain is the maximum sound pressure level that can be tolerated without causing discomfort or damage.

Psychoacoustics is the scientific study of sound perception, specifically how humans perceive and interpret sound. It focuses on understanding the psychological and physiological processes that occur when we hear sounds, including the perception of pitch, loudness, and timbre. This field of study helps researchers and scientists understand how our brains process and interpret sound, which has applications in various fields such as audio engineering, music psychology, and hearing aid design.

Reverberation time refers to the time it takes for the sound pressure in a room to decrease by 60dB after the sound source is stopped. It is a measure of how long a sound persists in a space after it is produced. A longer reverberation time indicates more reflections and a more "live" or echoey sound, while a shorter reverberation time indicates a more "dead" or absorptive sound environment. Therefore, in this context, reverberation time is the correct answer as it directly relates to the given scenario.

A combination central-distributed loudspeaker system uses a cluster of loudspeakers over the sound source, as well as additional speakers at the rear end of the hall or under balconies. This setup allows for a more immersive and balanced sound experience throughout the entire venue. By combining both central and distributed speakers, the system can provide clear and even sound coverage to all areas of the hall, ensuring that the audience can hear the audio without any distortion or imbalance.

Intensity is the correct answer because it refers to the rate at which sound energy is being transmitted and is measured at any point in the medium. It represents the sound power per unit area, indicating how strong or weak a sound is. Hertz, velocity, and volume are not appropriate choices as they do not directly measure the rate of sound energy transmission or sound power per unit area.

In the stage of lighting design called "Finalizing," the designer evaluates the design to ensure that it meets the desired objectives and specifications. This involves reviewing the conceptualized design, making any necessary adjustments or refinements, and ensuring that all aspects of the design are cohesive and well-executed. The finalizing stage is crucial in ensuring that the lighting design is ready for implementation and meets the desired aesthetic, functional, and technical requirements.

A distributed loudspeaker system uses multiple low level overhead loudspeakers placed throughout the auditorium. This allows for sound to be evenly distributed and provides a more immersive experience for the audience. Unlike a central loudspeaker system, which typically uses a single speaker, a distributed system ensures that sound reaches all areas of the auditorium equally. Additionally, a distributed system is different from a combination central-distributed system, which combines both central and distributed speakers to achieve optimal sound quality. A stereophonic system, on the other hand, refers to a system that produces two separate audio channels to create a sense of depth and directionality in sound.

Loudspeakers are devices that convert an electric signal into sound waves that can be heard by listeners. They are responsible for distributing the sound in the air, allowing it to be heard in a room or an outdoor area. Amplifiers are used to increase the power of the electric signal, while tweeters are a type of loudspeaker that produces high-frequency sounds. Therefore, the correct answer is loudspeakers as they are specifically designed to convert the electric signal into airborne sound waves for distribution to the listeners.

Coaxial units refer to a loudspeaker system where the individual driver units radiate sound from the same point or axis. This means that the tweeter and subwoofer are aligned in such a way that they emit sound from the same location, resulting in a more coherent and focused sound output. This design allows for better integration of the different frequency ranges, resulting in improved audio quality and a more accurate representation of the original sound source.

Porous materials have a cellular network of interlocking pores, which is their basic acoustical characteristic. This allows sound waves to enter the material and get trapped within the pores, leading to absorption and attenuation of the sound energy. As a result, porous materials are commonly used in various applications, such as soundproofing, noise control, and acoustic treatment, to reduce unwanted echoes, reverberation, and overall sound levels in a space.

Sound absorption refers to the process of reducing the reflection of sound waves, thereby reducing the overall sound level in a space. Frictional, flexural, and resonating are all methods of sound absorption as they involve the absorption of sound energy through various mechanisms. Diffusion, on the other hand, refers to the scattering of sound waves in different directions, rather than absorbing them. Therefore, diffusion is not a method of sound absorption.

The correct answer is Conceptualizing. In the stage of conceptualizing in lighting design, the designer focuses on creating a concept or idea for the lighting design based on the building program and task analysis. This involves brainstorming and developing initial design concepts that align with the project goals and requirements. This stage is crucial for establishing the overall direction and vision for the lighting design before moving on to the more detailed development and finalization stages.

Developing is the correct answer because at this stage of lighting design, detailed calculations are performed. This involves determining the appropriate lighting levels, fixture placement, and power requirements for the project. It is a crucial step in the design process as it ensures that the lighting design meets the necessary technical and functional requirements. Scheming and conceptualizing are earlier stages where initial ideas and concepts are explored, while finalizing is the last stage where the design is reviewed and approved.

The central loudspeaker system is the preferred type because it uses a single cluster of loudspeakers placed centrally over the sound source. This setup allows for maximum realism in sound reproduction as the sound is projected from a single point, creating a more focused and immersive listening experience.

Electro Acoustics is the correct answer because it specifically focuses on the generation and detection of audible sound waves, as well as sound reproduction. This field combines principles of electrical engineering and acoustics to study the interaction between electrical signals and sound waves. It involves the design and development of audio systems, such as microphones, speakers, and amplifiers, as well as the study of how electrical signals are converted into sound waves and vice versa.

Footcandles is the correct answer because it is a unit used to measure illuminance, which is the amount of light falling on a surface. Lumens per square foot (Lumens/SF) is a common way to express illuminance, and footcandles is another unit that represents the same concept. Therefore, Lumens/SF is equivalent to footcandles.

Sound refraction refers to the change in the direction of a sound wave as it passes from one medium to another with a different density. This change in direction occurs due to the variation in the speed of sound in different materials. When the sound wave encounters a boundary between two materials, it can bend or change its path, leading to the phenomenon of sound refraction.

Panel or membrane absorbers are impervious materials that are installed in a solid backing but separated from it by an air space. These absorbers are designed to absorb sound energy by converting it into heat through the vibration of the panel or membrane. The air space between the absorber and the solid backing helps to improve the absorption performance by allowing sound waves to pass through and be absorbed by the panel or membrane. This design allows for effective sound absorption and helps to reduce echo and reverberation in a space.

A stereophonic system employs two or more microphones adequately spaced in front of the performing area and connected through separate amplifying channels to two or more corresponding loudspeakers. This allows for a more immersive and realistic sound experience, as the different microphones capture different aspects of the performance and the separate amplifying channels and loudspeakers reproduce the sound in a way that simulates the spatial positioning of the original sound sources.

The correct answer is "Scheming." In the stage of lighting design, scheming involves both the preliminary design and detailed design. It includes conceptualizing ideas and developing them further to create a final lighting design plan. This stage is crucial as it lays the foundation for the overall lighting design process, allowing designers to explore different concepts and finalize the most suitable design approach.

Cavity (Helmholtz) resonators are materials that consist of an enclosed body of air, confined within rigid walls and connected by a narrow opening to the surrounding space. This design allows for the absorption of sound waves at specific frequencies, as the air inside the resonator vibrates in response to the sound waves. This vibration helps to dissipate the sound energy and reduce its reflection, making cavity resonators effective in sound absorption and diffusion applications.