Properties of Sound Class Test

Chapters 1-6

Sound

Sound is a mechanical disturbance in a medium.

Physicists describe sound in terms of _____.

Waves

Sound Wave Propagation’s movements’ are:

Compressions and Rarefactions

Longitudinal wave propagation

The sound is travelling in the same direction as the particle movement.

Compressions are areas of;

High Pressure

Rarefactions are areas of:

Low Pressure

Velocity

Speed in a given direction

Acceleration rises from

A change in speed or direction

The Speed at which sound travels through a medium depends on

The Mass of the Molecules and (often determined by density) and the strength of the intermolecular forces.

Density

Mass per unit volume

Name something that does not have a Young’s Modulus:

Air

What do you do to convert a Kelvin Temperature to Celsius?

+273

How is sound represented in a DAW?

Pressure/Time (Time-pressure domain)

What is Frequency given as?

cycle-per-second (hertz)

What is a cycle defined as?

Compression followed by Rarefaction (or vice-versa)

Name the parameters defining a periodic waveform:

Phase, Wavelength, Frequency, Period, Amplitude

Frequency is the ______ of the period?

Inverse

What is the range of human hearing?

20Hz - 20,000Hz

What is the range of human hearing in terms of wavelength?

1cm - 17m

Waveforms can be divided into;

Periodic and Aperiodic

Periodic Waveforms can be divided into:

Simple (single Sinewaves) and Complex (Multiple Sinewaves)

Aperiodic Waveforms can be divided into:

Continuous (noise) and Transient (pulse)

Amplitude

The measure of the amount of pressure in a wave.

Instantaneous Amplitude

Measure of the pressure in a wave at a set moment in time and space.

Peak Amplitude

Maximum pressure variation in a waveform

RMS Amplitude

Root mean squared amplitude/Time

RMS Amplitude can only be zero if;

There is no sound.

Relationship between energy and amplitude:

Energy is Proportional to Amplitude Squared

Sound Power Level

A measure of the total power radiated by a source of sound.

Sound Pressure Level is given in;

Decibels

Timbre

Timbre is why the same note on different instruments don’t sound the same.

Composite waveforms are made up of a sum of _________ sinusoidal waves.

Infinite

The average of two sine waves will be zero if;

They don’t have the same frequency.

Each harmonic are spaced apart by _______ Hz.

55

Our perception of musical pitch is linear.

False

Sine waveforms contain ___ harmonics.

Only

Sawtooth waveforms contain ___ harmonics.

all

Square waves contain only ___ harmonics.

odd

Triangular waveforms contain only odd harmonics but the amplitude is;

1/Harmonic Number Squared

Sounds reflect whenever they meet a _________ in a medium.

discontinuity

The three main behaviours of a wave hitting a discontinuity are:

Reflection, Diffraction, Refraction 

What is the largest wave that will fit between two boundaries?

Half a wavelength.

The Principal of Superposition

Waves cannot affect one another.

Refraction

The bending of a wave as it passes from one medium to another.