1.2 Data Rep: Sound

Is 'real' sound analogue or digital?

• Analogue

• Digital

How is sound caused?

• By playing it through a hi-fi with speakers
• Vibrations travelling through air, water or metal.

The amplitude of a sound wave is....

• How high the wave is from the crest or trough
• The frequency at which it is sampled
• The speed at which it travels through air

The pitch of the wave is shown by.....?

• The closeness of the wave
• The height of the wave

Define what is meant by 'sampling'

• Height of the wave is measured, at intervals and stored as binary.

• The number of samples taken each second

•  The number of bits used per second of audio

• The amount of information required to describe one second of a sound.

Define the term 'sample rate'.

• Height of the wave is measured, at intervals and stored as binary.

• The number of samples taken each second

•  The number of bits used per second of audio

• The amount of information required to describe one second of a sound.

Define what is meant by 'bit depth'

• Height of the wave is measured, at intervals and stored as binary.

• The number of samples taken each second

•  The number of bits used per second of audio

• The amount of information required to describe one second of a sound.

Define what is meant by 'bit rate'

• Height of the wave is measured, at intervals and stored as binary.

• The number of samples taken each second

•  The number of bits used per second of audio

• The amount of information required to describe one second of a sound.

Which three factors affect the quality of an audio clip?

• Bit rate and bit depth
• Bit rate, bit depth and number of pixels
• Sample rate, analogue, number of pixels
• Sample rate, bit rate and bit depth

How do you calculate the bit rate of a digital audio file?

• Frequency x channels
• Frequency × bit depth × channels 
• Bit depth x channels
• Channels x 2 x bit depth