Equalisation (EQ)

Question 1

What is EQ

Answer 1

The process by which different frequency ranges are increased or decreased in volume

Question 2

What is a filter

Answer 2

A filter lets some of the audio signal through without changing it, but will cut or boost the signal level of a specific frequency range

Question 3

What is a cutoff frequency in a filter

Answer 3

It determines which frequencies will be passes unaffected and which frequencies will be removed

Question 4

What is centre frequency in a filter

Answer 4

Determines the frequency around which a band pass filter allows frequencies to pass through

Question 5

What is gain in a filter

Answer 5

Determines how much cut or boost is applied to the affected frequencies

Question 6

What is resonance in a filter

Answer 6

Characteristic narrow boost of the frequencies around the cutoff, which makes the sound ‘whistly’ or if over used introduces self oscillation

Question 7

What is the slope of a filter

Answer 7

Determines how sharply the filter will act at its cutoff frequency - measured in dB

Question 8

What is a band bass filter

Answer 8

It is essentially a combination of an LPF and an HPF, which allows a centre range of frequency to pass unaffected and removes those on either side outside of the range

Question 9

What is used in a wah wah pedal

Answer 9

A band pass filter where the centre frequency is swept to give the characteristic effect

Question 10

What is the main difference between a semi parametric EQ and a parametric EQ

Answer 10

You can change the Q (bandwidth) on a parametric EQ

Question 11

What is a shelving filter

Answer 11

They allow the user to cut or boost the signal beyond a specific frequency, which is then evenly applied until the end of the audio spectrum, leaving the rest of the signal unaffected, their graphs look a bit like a shelf

Question 12

What are low and high shelf filters usually used for

Answer 12

• a low shelf can be used to increase the low frequencies in a kick drum or a bass guitar
• a high shelf boost is often used to bring something forward in the mix or to add clarity to drum overheads

Question 13

Give a overview of a parametric EQ

Answer 13

They work using a number of different types of filter. They tent to show a overall curve which is creates by combining all of the filters, and are often seen on DAWs, software and digital effects and processors

Question 14

Give an overview of a graphic EQ

Answer 14

They use a bank of filters which are used to individually boost or cut specific parts of the frequency spectrum, the labels on the EQ sliders are fixed centre frequencies of each filter and these represent the middle of each band, the Q of each filter is also fixed. They are commonly used in live sound to correct the frequency response of a room/speaker system.