Equalization

1
Equalization

• EL2071 Audio 2

2
Equalization

• an equalizer is a sophisticated tone control
• add crispness to dull cymbals
• add bite to a wimpy electric guitar
• remove tubbiness from a close-miked vocal

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Frequency spectrum

• each instrument or voice produces a wide range of
  frequencies
• fundamentals and harmonics which give each
  instrument its distinctive tone and character
• boost or cut certain frequencies change the
  quality of sound

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Four (or five?) types of equalizer

• Basic bass and treble control

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Four (or five?) types of equalizer

• Three-band boost or cut lows, mids, highs at
  fixed frequencies

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Four (or five?) types of equalizer

• Sweepable tune in to the exact frequency range
  needing adjustment
• one knob sets centre frequency, another sets
  amount of boost or cut (in dBs)

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Four (or five?) types of equalizer

• Parametric set frequency, amount of boost/cut
  and bandwidth range of frequencies affected

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Filters

• A filter causes a rolloff at frequency extremes
• lowpass
• highpass
• bandpass

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Filters - examples

• 10 kHz lowpass (high-cut) filter removes
  frequencies above 10 kHz
• reduces hiss-type noise
• 100 Hz highpass (low-cut) filter attenuates
  frequencies below 100Hz
• removes low-pitched noises such as traffic
  rumble, breath pops
• 1 kHz bandpass filter cuts frequencies above and
  below a frequenccy band centred at 1 kHz

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Filters - examples
11
How to use EQ

• (consult handout on instrument fundamentals and
  harmonics)
• Turn up lower end of fundamentals to get warmth
  and fullness
• Turn down fundamentals if tone is too bassy or
  tubby
• Turn up harmonics for presence and definition
• Turn down harmonics if tone is too harsh or
  sizzly

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When to use EQ

• First, try to get desired tone quality by
  changing the mic or its placement
• This gives a more natural effect than EQ

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When to use EQ

• Improve tonal quality
• high frequency roll-off to reduce sibilance on a
  singer
• cut around 250 Hz on a bass guitar for clarity
• Create an effect
• sharply rolling off lows and highs on a voice
  gives a telephone sound

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When to use EQ

• Reduce noise and leakage
• kick drum has no output above 9 kHz, so filter
  out highs above that to reduce cymbal leakage
• filter out frequencies below 100 Hz on most
  instruments reduces rumble, breath pops

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When to use EQ

• Make a pleasing blend in the mix
• two instruments that sound a like e.g. lead and
  rhythm guitar, tend to mush together
• make lead guitar edgy by boosting 3 kHz
• make rhythm guitar mellow by cutting 3 kHz
• similarly, bass and kick drum fatten one, thin
  out the other