Sound

Question 1

What does a microphone do?

Answer 1

Converts sound into an electrical signal

Question 2

Once the microphone has converted sound into an electrical signal, where does this signal then go?

Answer 2

To the ADC (Analogue-to-Digital converter) in the sound card

Question 3

What are the 2 jobs of a sound card?

Answer 3

To convert an analogue signal into a digital one for storage

To convert stored digital signals into an electrical signal to send to the speakers

Question 4

How do speakers replay a sound?

Answer 4

The file is opened and the binary numbers are fed through the DAC (digital-to-analogue converter) which is then amplified to produce enough power for the speaker

Question 5

What is the frequency of sound measured in?

Answer 5

Hertz (Hz)

Question 6

What is amplitude?

Answer 6

How loud or quiet the sound is

Question 7

What is sampling?

Answer 7

A method of converting an analogue sound signal into a set of binary numbers that are then stored in a digital file

Question 8

What happens when sampling?

Answer 8

To take measurements of the amplitude of the sound wave at various points in time

Question 9

What is the sampling frequency?

Answer 9

The rate at which samples are taken

Question 10

What is the sampling frequency usually measured in?

Answer 10

Kilohertz (thousand times per second)

Question 11

What is the Nyquist Theorem?

Answer 11

The minimum sampling rate is at least twice the highest frequency in the signal

Question 12

What is sampling bit depth?

Answer 12

The number of bits which are used per sample

Question 13

What is a channel?

Answer 13

A single sound stream

Question 14

What is mono sound?

Answer 14

Mono sound has information about only a single source, or “channel”

Question 15

What is stereo sound?

Answer 15

Stereo or Surround sound will have multiple channels, to make use of multiple speakers. Each of these channels will need to have its own samples

Question 16

What is the equation to work out bit rate?

Answer 16

Bit rate = sample rate x bit depth x number of channels

Question 17

What is the bit rate?

Answer 17

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

Question 18

What is the unit for bit rate?

Answer 18

Bits per second

Question 19

What is the equation to work out file size?

Answer 19

File size (bits) = bit rate x length

Question 20

What is metadata?

Answer 20

Additional basic information on top of the samples, in order for an audio player to play back a sound file

Question 21

What 4 things are included in basic metadata of a sound file?

Answer 21

Sample rate
Bitrate
Length
Codec (a device or computer program for encoding or decoding a digital data stream)

Question 22

What is Codec short for?

Answer 22

Code Encode

Question 23

What does Codec describe?

Answer 23

The algorithm used to create and play back the file

Question 24

In MP3 files, what 5 common tags are included in the metadata?

Answer 24

Title of song
Artist
Track number
Year
Album

Question 25

What is a uncompressed sound format called?

Answer 25

WAV

Question 26

What is a compressed sound format called?

Answer 26

MP3

Question 27

What does a higher bit depth mean?

Answer 27

Better sound quality

Question 28

What does a faster sampling rate cause for the size of the file?

Answer 28

A larger file size