Sound Flashcards
What does a microphone do?
Converts sound into an electrical signal
Once the microphone has converted sound into an electrical signal, where does this signal then go?
To the ADC (Analogue-to-Digital converter) in the sound card
What are the 2 jobs of a sound card?
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
How do speakers replay a sound?
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
What is the frequency of sound measured in?
Hertz (Hz)
What is amplitude?
How loud or quiet the sound is
What is sampling?
A method of converting an analogue sound signal into a set of binary numbers that are then stored in a digital file
What happens when sampling?
To take measurements of the amplitude of the sound wave at various points in time
What is the sampling frequency?
The rate at which samples are taken
What is the sampling frequency usually measured in?
Kilohertz (thousand times per second)
What is the Nyquist Theorem?
The minimum sampling rate is at least twice the highest frequency in the signal
What is sampling bit depth?
The number of bits which are used per sample
What is a channel?
A single sound stream
What is mono sound?
Mono sound has information about only a single source, or “channel”
What is stereo sound?
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
What is the equation to work out bit rate?
Bit rate = sample rate x bit depth x number of channels
What is the bit rate?
The amount of information required to describe one second of a sound
What is the unit for bit rate?
Bits per second
What is the equation to work out file size?
File size (bits) = bit rate x length
What is metadata?
Additional basic information on top of the samples, in order for an audio player to play back a sound file
What 4 things are included in basic metadata of a sound file?
Sample rate
Bitrate
Length
Codec (a device or computer program for encoding or decoding a digital data stream)
What is Codec short for?
Code Encode
What does Codec describe?
The algorithm used to create and play back the file
In MP3 files, what 5 common tags are included in the metadata?
Title of song Artist Track number Year Album
What is a uncompressed sound format called?
WAV
What is a compressed sound format called?
MP3
What does a higher bit depth mean?
Better sound quality
What does a faster sampling rate cause for the size of the file?
A larger file size
