EQ Basics Explained

EQ Basics

Here at Music Production Headquarters we will be covering EQ basics. In this article you will learn about the following.

• What is an equalizer
• Different types of equalizer
• What a high and low pass filter is and how they can be used
• What shelf filters are and how they are used
• What a notch filter is
• What the slope of an EQ is
• What a Q is and how to calculate it
• 3 tips you can use now to better use EQ
• EQ starting points for many instruments that you may encounter

What Is An Equalizer / EQ?

An equalizer is a device which alters the relative strength of a certain frequency ranges in an audio signal.

Different Types of Equalizer / EQ

Fixed frequency EQ: Basic type of EQ in which the various bands are set to certain frequencies and cannot be changed; only the level of the bands can be adjusted.

Sweep EQ: An EQ in which the various bands are adjustable in frequency, in addition to adjusting the level ( gain) of those bands.

Parametric EQ: A sweep EQ that permits adjusting the range (bandwidth) of frequencies affected on either side of the targeted frequency.

Graphic EQ: A type of fixed frequency equalizer which offers several different bands spread in octaves of divisions of octaves across the frequency spectrum. Typically used to equalize an entire system to the room.

What is a High Pass, Low Pass, and Notch Filters?

High and Low Pass Filters that pass certain frequencies at full level, which attenuating others. Often referred to as “roll off”, it gradually attenuates below or above frequencies.

The tricky thing about low and high pass filters is that the low pass will allow the low frequencies to pass unchanged, but it will not allow higher frequencies that the user specifies.

Shelving filter: Increased or decreased gain at a selected frequency, and continues at this level to the end of the audible spectrum. Commonly found on a home stereo’s bass and treble controls.

Notch Filers: A device which can create a very steep drop or boost in the frequency response of a signal at a very specific narrow frequency band

Slope: The rate at which a high/low pass filter attenuates or boosts frequencies. Usually referenced as dB per octave

The Quality Factor

Usually referred to as “Q width” – the width of the bell-shaped curve representing bandwidth. Typically used in identifying parametric EQ parameters.

To determine the Q factor of an EQ filter, the formula is the following

Center Frequency /Bandwidth ( reference to +- 3dB)

3 EQ Tips You Can Use Now!

1. Cut before boosting EQ frequencies. It is easier to remove a frequency then it is to add more
2. When cutting or boosting normally 3dB is enough of a boost or cut
3. When looking for a trouble frequencies create a notch filter boost it by 12dB and then sweep it through the frequency spectrum slowly until you find the trouble frequency. Once the trouble frequency is found the next step is to reduce the gain down to 1-3 dB and listen. Adjust the Q as needed.

EQ Starting Points

Vocals

• Bottom 120Hz – 180Hz
• Resonance 200Hz – 240 Hz
• Articulation 4k to 50k

Strings

• Fullness at 240Hz
• Bow resin at 7.5k to 10k

Brass/Horns

• Fullness at 120Hz to 240Hz
• Brightness/shrill at 5k to 7.5K

Acoustic Piano

• Bottom at 80Hz to 120Hz
• Presence at 2.5k to 5k

Acoustic Guitar

• Bottom 80Hz to 120Hz
• Resonance/body 240Hz
• Clarity at 2.5kHz to 5Khz

Electric Guitar

• Thickness 240Hz
• Bite 2.5k to 3k

Bass Guitar

• Thunder 60Hz to 80Hz
• Attack/pluck at 700Hz to 1Khz
• Fret Buzz/pops 2.5k

Floor Toms

• Resonance 80Hz to 120hz
• Attack 4K-5K

Rack Toms

• Resonance 240Hz
• Attack 4K to 5K

High Hat / Cymbals

• Clang 200Hz
• Shimmer 75k to 12k
• Sparkle upper harmonics 13k – 15k

Snare Drum

• Thickness 240Hz
• Crispness 5K

Kick Drum

• Bottom Depth 60Hz to 80Hz
• Articulation/slap attack 2.5k

Organ

• Bottom 80Hz – 120hz
• Body 240Hz
• Presence 2.5k to 3K

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