EQ and Frequency

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EQ and Frequency

EQ

Specifies

the frequencies (dB) across the spectrum of EQ (Hz)

Short for

equalisation, is the process of amplifying or attenuating specific or groups

of frequencies to alter the tone of targeted audio signal.

LPF

An EQ Filter

which reduces/ removes high frequencies whilst allowing the low frequencies

to pass unedited.

Lowpass

filters affect signals, attenuating above a set frequency with a progressive

gain slop per octave.

HPF

An EQ Filter

which reduces/ removes low frequencies whilst allowing the high frequencies

to pass unedited.\

Highpass

filters affect signals, attenuating below a set frequency with a progressive

gain slop per octave.

BPF

An EQ

Filter which signals between to specific frequencies to pass – inner – whilst

discriminating against signals at other frequencies.

Affect signals,

amplifying or attenuating either side of a specified centre frequency, the

scope of which is determined by a bandwidth control (Q)

Notch

Filters

Passes

most frequencies unaltered whilst attenuating certain frequencies of a

specific range to very low levels.

A more

intense form of BDF, it focuses on a very specific frequency with a narrow bandwidth

(Q) to help remove noises.

Shelving

Filters

A

shelving filter applies cut or boost to frequencies above or below the filter

cut-off point.

These

affect signals both above (high shelving) and below (low shelving) with equal

gain curves, measured as a bandwidth (Q).

Frequency

is created from the dot (along the middle of the curve) – not on the line

etc. gain slope etc.

Parametric

EQ

Devices

that allow the control of multiple frequencies, often with multiple BPFs that

amplify or attenuate a specific narrow spectrum of frequencies.

Graphic

EQ

Devices

that amplify or attenuate set frequencies across the spectrum. These were

commonly found on associated with domestic hi-fi units.

Frequency

Number of

vibrations per second, measured in hertz (Hz).4

Centre Frequency

A

specific frequency, e.g. 400Hz

Gain

Measured in

dB, used to amplify or attenuate targeted frequencies.

Bandwidth

(Q)

Used to control

the scope of frequencies affect (wide or narrow).

Slope

Extent by

which a LPF or HPF attenuates a signal in dB per octave.

Cut-off

frequency

Frequency

at which a LPF HPF or BPF impacts upon signal.

Resonance

Involves

the amplification of frequencies around the centre frequency, often with a

BPF, often producing/amplifying harmonics/overtones.

White noise in synthesis : Frequencies

of white noise – amplify different points through alternating cutoff. Resonance

amplifies centre frequency. Moving cutoff value creates additional

overtones/harmonics – pitch.