Lecture 9-Effects

Question 1

What are effects processors?

Answer 1

Hardware units or audio plug-ins that can subtly ‘colour’ a sound, or change it radically.

Question 2

Where can you find effects processors?

Answer 2

Recording studio/pro tools

Question 3

Give three examples of audio effects:

Answer 3

Distortion, delays, reverbs.

Question 4

Define distortion:

Answer 4

Used in film and TV to stimulate broken/overdriven telephones/loudspeakers. It is also used in non-diegetic sound effect.

Question 5

Define delays:

Answer 5

A delay effect is one that repeats the input audio signal after a dictated length of time, typical parameters: delay time: how long between repetitions, feedback:dictates the number of repetitions, EQ and filters: applies EQ to the delays. Panning:pans the delays in the stereo field. Dry/wet ratio or mix:dictates how much of the delayed signal we hear.

Question 6

Define reverberation:

Answer 6

Allows us to take a dry audio signal and place it in a virtual acoustic environment.

Question 7

Room acoustics:

Answer 7

Components of the received sound: direct sound, early reflections, reverberant sound.

Question 8

Room acoustics diagram:

Answer 8

DIRECT FIELD (drop of 6dB/doubling distance)- CRITICAL DISTANCE - DIFFUSE FIELD (sound level will remain constant.

Question 9

Reverberation time:

Answer 9

The time in seconds that it takes for sound to decay by 60dB after the sound source in question has stopped. Suitable control rooms typically have an RT60 of 0.3s.
Live rooms may vary from 0.5-1.5

Question 10

Define mono:

Answer 10

One channel of audio- same signal sent to both the left and right speakers or the left and right side of the headphones.

Question 11

Define stereo:

Answer 11

2 channels of audio: different signals are sent to the left and right loudspeakers, the signals were recorded with microphones set up in particular ways.

Question 12

What makes good approximation in digital recording?

Answer 12

We need at least twice the number of sample points per second as the highest frequency in a signal. If we consider the hearing range is up to 20kHz we need 40,000 sample points every second. Nyquist sampling theorem.

Question 13

Define bit depth:

Answer 13

Number of bits available for each sample. The higher the bit depth the higher the quality of the audio, the more data is captured to recreate the sound accurately. The higher the bit depth the more precise. Each extra bit- 6dB increase in dynamic range - less noise, higher signal to noise ratio (SNR).