Fundamentals of sound Flashcards
1
Q
What is sound?
A
- Sound moves in air through a vibration causing a disturbance in air particles
- This causes them to move towards each other and transfer the vibration to our eardrum
2
Q
What are the two main properties of sound?
A
Frequency and amplitude
3
Q
What is a wave cycle
A
- A complete wave that moves from 0, through its maximum and minimum and back to zero again
- The cycle can be measured from peak to peak or trough to trough - this is the wavelength
- If a wave completed one cycle in a second, it would have a frequency of 1Hz.
4
Q
What is the period?
A
- It is the time taken for the wave to complete 1 cycle
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5
Q
How is amplitude measured?
A
- Measured in decibels (dB)
6
Q
What is phase?
A
- If sound waves are out of phase, the peaks and troughs do not line up
- Phase must be considered when recording with two microphones or from either side of a drum
- Many mixers include phase invert/switch buttons, which swaps the signal to solve the problem
7
Q
What is interference?
A
- When two or more waves come together to add or subtract their energy
8
Q
What are two methods of treating a room for audio recording?
A
Absorption and Diffusion
9
Q
What is absorption?
A
- Aims to minimise reflections caused by hard parallel surfaces
- Lessens reverb effects, giving a clearer listening
- Higher frequencies are easier to control, but taming lower frequencies can be more complicated
10
Q
What is diffusion?
A
- ## Aims to break up repetitive echoes caused by parallel walls
11
Q
What are bass traps?
A
- Often added to room corners where bass frequencies build up, to absorb the bottom end and prevent low frequencies from bouncing back into the room.
12
Q
What is reducing spill?
A
- When multiple sound sources occur in a room, they will be picked up on microphones that have been set up to record other sound sources
- Modern techniques include isolation booths and acoustic barriers
