Representing Sound Flashcards
What is digital(sound)
Data that takes the form of discrete values
What is analogue(sound)
Data that varies in a continuous manner
What is sampling resolution(sound)
Number of bits assigned to each sample
What is sampling rate(sound)
Number of samples per second, measured in Hz
What is Quantisation(sound)
Rounding the sample value as a binary number
What is the process of recording sound from a microphone to a file
-First pick up the sound waves using a microphone. Converts into analogue electrical signals
-These signals are then processed by an analogue to digital converter(ADC), which converts the signals into digital values in a process called sampling
What is the process of playing a digital audio file
-Convert the sound from digital values stored on computer into analogue electrical signals, using a digital to analogue converter (DAC)
-These signals are then passed to a speaker which vibrates the speaker cone to create analogue sound waves
What is the process of sampling(sound)
-Taking measurements of the amplitude of the analogue signals at regular intervals
-These are then quantised into a binary pattern and stored in memory
How do you find the size of an audio file
(Sample rate x 2) x time x size of each sample = size
What is MIDI(storing sound)
Music information digital interface
Used for recording and synthesising musical instruments
Editable files smaller in size
What is WAV(storing sound)
Used on CDs for editing
What is MPEG(storing sound)
Lossy compression
Removes frequencies that humans cannot hear (outside range 20Hz - 20KHz)
How is MIDI used to synthesise music
Digital data is stored in the form of ‘event messages’ which detail the note to be played, the duration of the note, how loud it is
Name an advantage of using MIDI to store music
-Versus other digital audio files, MIDI files are smaller
-Files are editable
-Wide range of instruments supported
-MIDI files can produce a high quality authentic reproduction of each instrument
