Equalisation Flashcards
What is EQ?
Equalisation is a process by which different frequency ranges can be boosted or cut in amplitude
What can EQ be used for
Create separation
Filter out a specific frequency
Adjust the tone of a sound
Create sound effects
Creating filter sweeps
What is an LPF
Low pass filter / high cut filter
What does a LPF do
Allows frequencies lower than the cut off frequency to pass through unaffected and cuts away frequencies higher than the cut off
What does the slope of the low pass filter determine
How abruptly the removal of frequencies occurs
What is the slope measured in
Decibels per octave
What is a HPF
High pass filter / low cut filter
What does a HPF do
Allows frequencies higher than the cut off frequency to pass through unaffected and cuts away the frequencies lower than the cut off
What can a HPF do
Used as a switch on microphones or mixing desk channels
Reduce unwanted low frequency sounds: plosives, electrical mains hum
What is a BPF
A band pass filter
What does a BPF do
Acts like a combination of LPF and HPF filters
Cuts frequencies either side of the centre frequency
What is the BPF also referred as
Telephone eq effect
What is a peak filter
Let’s you cut or boost the amplitude of a band of frequencies around a centre frequency
What is a notch filter
A very narrow peak filter cut and have a high Q value
Can be used to eliminate specific frequencies such as intrusive resonance
What is a shelving filter
Shelving filters boosts or cuts the amplitude evenly across all frequencies above or below the centre frequency
What does a high shelving filter do
Used as a mixing tool
Boosts or cuts all frequencies higher than the cut off by an equal amount
What does a low shelving filter do
Boosts or cuts all frequency lower than the cut off by an equal amount
Can be used to add extra weight to all the low frequencies in a recording
What is resonance
Resonance occurs when the frequencies around the cut off are boosted on an LPF or HPF
What are the different types of an eq unit
Parametric eq
Semi parametric eq
Graphic eq
What does a parametric eq do
Combine a number of different filter types and allows you to adjust all the parameters for these filters
What does a semiparametric eq do
Combines the output of a number of different filter types
Often found on each channel of an analogue mixing desk
What does a graphic eq do
Use a bank of fixed frequency peak filters which are used to individually boost or cut specific parts of the frequencies spectrum
