Does something sound ‘off’ with your speakers or headphones? Do the stringed instruments sound like clinking silverware, or is the bass so overpowering that it feels like you’re listening to music underwater? If so, the equipment itself may not be to blame. You may be dealing with an equalisation issue — one that’s easily corrected by adjusting the loudness of the specific frequencies in your sound’s source signal.

It can help to think of equalisation, or EQ, as a kind of volume control, only instead of adjusting the overall loudness of your music, EQ lets you tweak specific frequencies independently. This can be a powerful tool when you want to correct problems like muddiness or harshness, but EQ can also be used in more creative ways, allowing you to shape the perfect blend of lows, mids, and highs for your sonic preferences.

If you’ve ever come across an ‘EQ’ or ‘Equalisation’ setting in your various audio apps, you may have felt overwhelmed by all the settings and sliders. The good news is that it’s actually pretty simple. With some basic knowledge about frequency ranges and a sense of what sounds good to you, you can start using EQ to improve your listening experience.

What is equalisation (EQ)?

Equalisation (EQ) is a tool that lets you adjust the volume of specific frequency ranges within audio. It's like having separate volume knobs for the deep bass, mid-range vocals and instruments, and high-pitched sounds that blend together to create an audio track.

So, why use EQ? It’s a good question, especially when you consider that most audio tracks have already been EQ'd multiple times before they reach your ears — at the mixing and mastering stages of recording, but also when they’re converted to different audio file types.

It helps to remember that sound is subjective. You may simply prefer your music with more pronounced bass, or with crisper mids and highs. But there are a few other reasons to tweak EQ as a listener.

One common reason is to accommodate different listening environments. The acoustic features of a room — its space, furnishings, reflections off surrounding walls, even the materials in its walls — can affect how you hear different frequencies of sound (This is why Sonos lets you tune your speakers to your room with Trueplay). If your music tends to sound muddy or harsh in certain listening environments, EQ can help clean this up. Another reason to tweak EQ is to optimise for different activities or media types. Listening to music during a workout? You may want to boost the bass for a more high-energy experience. Having trouble hearing the dialogue in a film despite its relatively loud volume? Try boosting the middle frequencies around 1–3 kilohertz, which can make voices ring out clearer. The bottom line is that different situations may benefit from different EQ settings

How do I adjust EQ?

You really don’t need to be an audio expert to adjust EQ. Most apps and streaming services these days offer an EQ in their playback settings menu under sections like ‘playback’, ‘content settings’ or ‘audio settings’.

These EQs typically come with simple sliders or buttons you can experiment with to tweak the character of your sound. Many apps provide simple presets with names like ‘bass booster’ or ‘treble reducer’ — simply toggle these on and see if they’re to your liking.

Popular streaming services like Spotify and Apple Music tend to offer genre-specific presets as well, so you can play around with ‘jazz’, ‘rock’, or ‘classical’ settings tailored to the music you listen to most. Just beware that these presets aren’t always perfectly labelled, and you may end up preferring the ‘classical’ setting for rap or heavy metal.

We suggest testing out different settings on a track you already know well, as you’ll be more in tune with how the track should sound to your ears.

Adjusting EQ on your Sonos system

Of course, there’s a problem with adjusting EQ within an app or streaming service: Your saved settings are limited to that app or service. That’s why it’s better to adjust EQ on a system level, so that your music sounds great across all of the platforms you may use.

With a Sonos sound system, you can adjust EQ across four dimensions: bass, treble, balance, and loudness. Here’s an overview of what each setting does:

• Bass: Adjusts the lower-frequency sounds, such as bass, or a kick drum.
• Treble: Adjusts the higher frequency sounds, such as guitar or vocals.
• Balance: Adjusts the volume level on the left or right audio channel. This
  option will only be available for rooms that can output stereo sound.
• Loudness: Boosts certain frequencies, including bass, during low
  listening volumes. This is designed to compensate for normal changes in
  the ear’s sensitivity when listening to audio at low volumes.

Simply drag the sliders to make adjustments, and your settings will be saved for all of the speakers, soundbars, headphones, and other components in your Sonos system. You can also create custom EQ settings for individual rooms in a multi-room audio setup, giving you the ability to tailor your sound to different listening environments.

How EQ affects different frequency ranges

Though many apps make it easy to adjust EQ with minimal technical knowledge, it may help to understand what an equaliser is actually doing to change the character of your sound.

As we noted above, EQ essentially works by raising or lowering the volume of specific frequency ranges within your music. But what types of sounds are produced by those specific ranges?

At a general level, we can break frequency ranges down into three bands: low, middle, and high. These frequency bands are measured in hertz (Hz), or the number of sound wave cycles that occur in one second. If that sounds too technical, just remember that lower numbers mean lower-pitched sounds and higher numbers mean higher-pitched sounds:

• Low frequencies (20 hertz to 200 Hz) are the rumbling bass sounds associated with subwoofer speakers. These can add a welcome dose of ‘oomph’ to a track, but too much bass can lead to instruments that sound muddy or ill-defined.
• Middle frequencies (200 Hz to 4 KHz) are where the vocals and lead instruments tend to be. If your mids are drowned out, vocals and guitar solos may seem a bit lost in the mix and a general sense of flatness may pervade.
• High frequencies (4 KHz to 20 KHz), also known as treble, may sound harsh or tinny when overrepresented in a mix. But there’s nothing like a crisp snare or cymbal crash to make a song come alive, so treble certainly has its place in the mix.

Some equalisation apps will only allow you to adjust frequency levels along these general lines, though others may let you tweak smaller frequency bands to craft a more fine-tuned sound. Parametric equalisers, for example, allow you to adjust minute aspects of the entire sound curve, rather than breaking the curve down into ranges that can be adjusted individually.

Regardless of the type of EQ you use, it’s good to know how raising or lowering different frequencies can affect your music’s overall sonic profile.

Which EQ is best for music?

By now, you should be able to guess that there’s no magical EQ setting that’s best for all types of music. The best EQ setting for you depends on your personal preferences as well as the type of music you listen to most.

We recommend playing around with different levels and seeing what works for you. And remember, it’s not always intuitive. You may think an EDM track demands more booming lows, but that track may already be mixed to emphasise the bass (and further boosting may do it no favours).

Here are a few additional guidelines to keep you on track:

• Hip-hop and rap may benefit from enhanced bass around 60–100 Hz for the kick drum punch. But also try giving it a boost in the mids (around 2–3 kHz) to keep the driving vocals front and centre.
• Rock and heavy metal tracks tend to sound more powerful with a boost around 100–250 Hz, which brings out the low snarling sounds of guitar and bass. An additional boost around 2-4 kHz can bring a little bite to go with all that bark.

Classical music tends to require gentler adjustments to EQ, or even none at all. Adjustments here should be more focused on moulding the sound to your space, with perhaps a small boost around 10 kHz to enhance the sense of room.

Find the perfect sound with Sonos

Equalisation can smooth out the ragged edges of your music and even highlight the parts you gravitate towards the most. Alas, there’s no EQ setting that can make up for poor-quality headphones or speakers. Instead of fiddling with the levels on a sub-par system in frustration, it’s worth upgrading to sound components that do your music justice in the first place.

At Sonos, we’ve designed premium headphones, speakers, and soundbars that redefine what’s possible with sound. Whether you’re taking music on the go with Sonos Ace or settling in with an immersive home-theatre experience courtesy of Arc Ultra, you never have to compromise on finding the perfect sound.

If you’re interested in taking your sound experience to the next level, get in touch with a Sonos expert by phone or chat.