Equalization (audio) facts for kids

An equalizer helps you adjust sounds.

Have you ever listened to a song and thought the bass was too loud, or the vocals weren't clear enough? That's where equalization comes in! In sound recording and playback, equalization is like a special tool that lets you change how loud different pitches of sound are. An equalizer is the device or software that helps you do this. It lets you make certain sounds louder or quieter, helping music or voices sound just right.

What is Equalization?

Equalization, often called "EQ," is all about shaping sound. Think of sound as having different layers, from very low rumbling sounds (like a bass drum) to very high whistling sounds (like a cymbal crash). These different layers are called frequencies.

How Does EQ Work?

An equalizer works by letting you control the loudness of these different frequencies.

• Low frequencies are the deep, bassy sounds.
• Mid frequencies are where most voices and instruments like guitars sit.
• High frequencies are the bright, crisp sounds, like cymbals or the "s" sound in speech.

By using an equalizer, you can turn up the bass if a song sounds too thin, or turn down the high sounds if they are too harsh. This helps to make the overall sound clearer and more balanced.

Why Do We Use Equalizers?

Equalizers are used for many reasons:

• To fix problems: Sometimes a recording might have too much hum or too much bass. An equalizer can help reduce these unwanted sounds.
• To make things sound better: You can make instruments stand out more in a mix or make vocals clearer.
• To create special effects: You can make a voice sound like it's coming from an old radio by cutting out the very low and very high frequencies.
• To adapt to different rooms: Every room sounds different. An equalizer can help adjust the sound system to make music sound good in any space.

Types of Equalizers

There are different kinds of equalizers, each with its own way of letting you control sound.

Graphic Equalizers

A graphic equalizer is one of the most common types. It has a series of sliders or faders. Each slider controls a specific frequency range.

• You can see a "graphic" representation of your sound adjustments.
• If you push a slider up, that frequency range gets louder.
• If you pull it down, it gets quieter.
• This type is easy to understand and use, as you can visually see the "shape" of your sound changes.

Parametric Equalizers

Parametric equalizers offer more detailed control. Instead of fixed frequency bands, they let you choose:

• Frequency: Exactly which pitch you want to adjust.
• Gain: How much you want to make it louder or quieter.
• Q (bandwidth): How wide or narrow the range of frequencies around your chosen pitch will be affected. A narrow "Q" affects only a small range, while a wide "Q" affects a larger range.

This type is often used by audio engineers for precise sound shaping.

Shelving Equalizers

Shelving equalizers are simpler. They boost or cut all frequencies above or below a certain point.

• High-shelf EQ: Affects all frequencies above a chosen point. Useful for making the overall sound brighter or darker.
• Low-shelf EQ: Affects all frequencies below a chosen point. Good for adding or removing bass from the overall sound.

Where Are Equalizers Used?

Equalizers are found in many places, from professional recording studios to everyday devices.

• Music Players: Many apps and stereos have built-in equalizers so you can adjust the sound to your liking.
• Car Stereos: You can often tweak the bass and treble in your car.
• Live Sound: Sound engineers use equalizers to make bands sound great in concert halls.
• Recording Studios: Essential for mixing and mastering music to get a polished, professional sound.
• Guitar Pedals: Electric guitarists use small equalizer pedals to shape their guitar tone.

Equalization is a powerful tool that helps us make audio sound its best, whether we're listening to music, watching a movie, or recording a podcast.

Images for kids

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  A stereo graphic equalizer. For the left and right bands of the sound content, there are a series of vertical faders, which can be used to boost or cut specific frequency ranges. This equalizer is set to a smiley face curve, in which the mid-range sound frequencies are cut.

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  Equalizers are also made in compact pedal-style effect units for use by electric guitarists. This pedal is a parametric equalizer.

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  The very uneven spectrum of white noise played through imperfect speakers and modified by room acoustics (top) is equalized using a sophisticated filter using digital hardware (bottom). The resulting "flat" response fails, however, at 71 Hz where the original system had a null in its response which cannot be corrected.

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  The equalizer-section from the Audient ASP8024 Mixing console. The upper section has high and low shelving EQ, the lower section has fully parametric EQ.