Sound Engineering Quiz

Measure of how much force is applied over a specific area.

Measure of how fast energy is transferred.

The natural frequency at which an object vibrates freely.

The points on a vibrating string that remain stationary.

The points on a vibrating string that have maximum displacement.

The type of wave where particles vibrate perpendicular to the direction the wave travels.

The type of wave where particles vibrate parallel to the direction the wave travels.

The ability of a wave to bend around an obstacle.

The difference in frequency between two simultaneous sine waves.

The frequency at which a system naturally vibrates when disturbed.

A frequency that is an integer multiple of the fundamental frequency.

A frequency that is not an integer multiple of the fundamental frequency.

The lowest natural frequency of a vibrating object.

Multiple sine waves added together where each frequency mode is harmonic with the fundamental frequency (integer multiples).

Multiple sine waves added together where not all frequency modes are integer multiples of the fundamental frequency.

The decrease in acoustic pressure as the distance from the sound source increases.

The A-weighted scale is used to measure sound levels, taking into account the sensitivity of the human ear to different frequencies. It's designed to reflect how we perceive loudness.

A transducer is a device that converts one form of energy into another. Microphones convert sound into electrical signals, while speakers convert electrical signals into sound.

An oscilloscope displays an electrical signal as a waveform over time, allowing us to see its amplitude and frequency changes.

ADCs convert analog signals (continuous) into digital signals (discrete), while DACs convert digital signals into analog signals. This process allows computers to work with audio signals.

A spectrum analyzer breaks down an electrical signal into its different frequency components, revealing which frequencies are present and their relative strengths.

An instrumentation system is a collection of devices that measure and control a process. It typically includes sensors, transducers, amplifiers, data processors, and controllers.

Absorptive materials reduce noise levels by converting sound into heat energy, while airtight materials prevent noise from entering or exiting a space. Porous and lightweight materials also contribute to sound absorption.

Reflected sounds that arrive more than 50 milliseconds after the direct sound, creating a distinct 'echo' effect.

A rapid succession of small echoes, resulting in a 'fluttering' or 'warbling' sound. This is caused by sound bouncing between two parallel reflecting surfaces.

Areas in a room where sound energy is significantly reduced, often due to destructive interference between sound waves. This results in a 'dead' or 'quiet' spot in the room.

Areas where direct sound reaches, but reflected sound is minimal, creating a 'shadow' effect. This occurs when sound waves are blocked by an object or when there are minimal reflecting surfaces.

Concentration of sound energy in specific areas of a room. This is caused by curved surfaces that focus the sound waves, leading to higher sound intensity in the focal points.

The time it takes for sound energy to decay by 60dB in a room. It's influenced by a room's volume and the amount of sound absorption by the materials in the room.

The total amount of sound absorption in a room, calculated by multiplying the surface area of each material by its absorption coefficient and adding them up.

The characteristics of sound that contribute to the overall listening experience in a room. These include spaciousness, intimacy, warmth, loudness, clarity, ensemble, and reverberance.

The visible part of the ear that collects and directs sound waves to the ear canal.

Leads sound waves to the eardrum.

Converts sound waves into vibrations and sends them to ossicles; it also protects the middle ear.

Three tiny bones (hammer, anvil, stirrup) that amplify vibrations and send them to the oval window.

Equalizes pressure in the middle ear.

Opening that allows sounds into the cochlea.

Fluid-filled structure that transmits vibrations into electrical signals for the brain.

Inside the cochlea, it distinguishes different frequencies of sound (higher to lower). Pressure differences in ducts move it.

The part of the basilar membrane that vibrates most at a given frequency.

• Low frequencies vibrate more near the helicotrema (apex of the cochlea).

• High frequencies vibrate more near the oval window (base of the cochlea).

Hair cells encode sound information in the inner ear.

• Intensity: The number of hair cells firing represents loudness.

• Frequency: The rate of hair cell firing and their location on the basilar membrane represent pitch.

• Spectrum: The complex sound pattern is encoded by the activation of multiple parts of the basilar membrane at once.

The range of frequencies around a specific tone that masks, or interferes with, its perception.

• Wider critical bands lead to more masking of neighboring frequencies.

• Tones closer together than a critical band mask each other more effectively.

The basilar membrane is asymmetrical. Different frequencies vibrate different parts of the membrane more effectively.

• Low frequencies mask higher frequencies more effectively due to the basilar membrane's asymmetry.

• Loud frequencies mask higher frequencies more effectively due to their greater amplitude.

Relationship between physical sound properties and their perceived qualities.

• Spectrum: The unique combination of frequencies present determines the perceived tone color or timbre.

• Frequency: The rate of sound wave vibrations determines the perceived pitch.

• Intensity or Sound Level: The amplitude of the sound wave determines the perceived loudness.

The subjective difference in loudness that can be detected between two tones.

• Factors that contribute to loudness perception:

  • Frequency of the tone
  • Individual's hearing sensitivity
  • Background noise
  • Adaptation to specific sound levels

Two tones are perceptibly different if the difference in their frequencies exceeds the just noticeable difference (JND).

• The JND varies depending on the frequency and intensity of the tones.

• Example: Two tones at 1000Hz with a 10dB difference in loudness are likely to be perceived as different.

The sound intensity at a specific distance is inversely proportional to the squared distance from the source. This means that when the distance from the sound source doubles, the sound intensity decreases by 6 dB.

A device that converts one form of energy into another. Examples include microphones (acoustic to electric), speakers (electric to acoustic), and magnetic pickups (mechanical to electric).

An electronic instrument that displays an electrical signal as a waveform over time. This allows you to see the changes in amplitude (strength) and frequency of the signal.

A device that converts an analog signal (continuous) into a digital signal (discrete). This process allows computers to work with sound data. It's like translating from spoken language to text.

A device that converts a digital signal (discrete) to an analog signal (continuous). It reverses the process of an ADC, allowing computers to output sounds from digital data.

An instrument that breaks down an electrical signal into its different frequency components. This reveals which frequencies are present in the sound and their relative strengths.

A system of devices used to measure and control a process. It typically includes sensors, transducers, amplifiers, data processors, and controllers. It's like the nervous system of a machine.

The natural frequency of a system is the frequency at which it vibrates most easily when disturbed. It depends on the system's physical properties like mass and stiffness.

The driving frequency is the frequency at which an external force is applied to a system. When the driving frequency matches the system's natural frequency, the system will resonate, achieving its largest amplitude.

The relationship between mass, stiffness, and resistance influences the frequency of a simple vibrator. More mass leads to lower frequency. More stiffness leads to higher frequency. Resistance (damping) doesn't change the natural frequency, but it affects the amplitude of the vibrations.

A simple vibrator is a system that moves back and forth regularly. The displacement, speed, potential energy, and kinetic energy of a vibrator change throughout its vibration cycle. The displacement is its position relative to its rest position. The speed is how fast it's moving. Kinetic energy is the energy of motion. Potential energy is stored energy.

Transverse waves have vibrations perpendicular to the direction of wave travel. Longitudinal waves have vibrations parallel to the direction of wave travel. Transverse waves can only travel through solids, while longitudinal waves can travel through solids, liquids, and gases.

A string fixed at both ends has several natural modes of vibration. These modes correspond to different patterns of standing waves on the string. Each mode has a specific number of nodes (points of no movement) and antinodes (points of maximum movement). The frequency of each mode is a multiple of the fundamental frequency.

The spectrum of a vibration represents the strengths of different frequency components present in the vibration. You can identify the amplitudes of each mode by looking at the spectrum. Each peak in the spectrum corresponds to a specific mode of vibration.

Sound waves are longitudinal waves that travel through a medium. Intensity refers to the power of a sound wave per unit area, which is related to the loudness we perceive. The intensity of a sound wave decreases as the distance from the source increases, following the inverse square law.

A sound wave is a longitudinal wave that travels through a medium such as air, water, or a solid. This means the particles of the medium vibrate parallel to the direction the wave travels, like compressions and rarefactions in a spring.

A transverse wave is a type of wave where the particles of the medium vibrate perpendicular to the direction the wave travels. This is like how a wave on a string moves, up and down, while traveling horizontally.

The distance between two successive condensations or rarefactions in a longitudinal wave is half a wavelength. To calculate the full wavelength, simply double this distance.

Increasing the tension of a string increases the speed of a wave traveling along that string. Conversely, increasing the density (mass per unit length) of the string decreases the wave speed.

Sound waves can be diffracted, reflected, refracted, experience the Doppler shift, and be absorbed by materials. Diffraction means bending around corners, reflection is bouncing off surfaces, refraction is changing direction in a medium, the Doppler shift is a frequency change due to motion, and absorption is when a wave's energy is taken in by a material.

Warm air makes sound waves travel faster than cold air. This difference in speed causes refraction, where sound bends as it moves from one temperature layer to another.

The time it takes an echo to return is directly proportional to the distance to the object. If you know the speed of sound and the time delay, you can calculate the distance to the object.

Sound waves bend downward when moving from hot air to cold air, and bend upward when moving from cold air to hot air. Thus, sound typically travels further at night when the ground is cooler than the air above.

Perceptual characteristics of sound in a room that impact the listening experience. Include spaciousness, intimacy, warmth, loudness, clarity, ensemble, and reverberance.