What Is Frequency Response and How It Affects Your Music

The frequency response shows how headphones and speakers reproduce each frequency from 20Hz to 20.000Hz. It compares the power of specific frequencies and compares them in a frequency response graph.

The frequency response graph tells us how headphones and speakers react to different sounds, so you can make them sound exactly how you want.

What Is Frequency Response?

The frequency response describes a range and energy of frequencies headphones can reproduce. You can get frequency response information in 2 ways.

• Frequency response information in specifications only tells the range of frequencies headphones can reproduce. But it doesn’t tell you how specific frequencies are boosted or reduced. Also, the frequency response range can be misleading. For example, specs for Sennheiser HD 650 state the driver can reach 10Hz, which might be technically accurate, but in reality, you don’t hear anything below 50Hz.

• Frequency response measurement is a graph showing precisely how much energy a headphone adds to individual frequencies or frequency ranges. It determines the sound signature of headphones, how good they are at imaging, the size of their soundstage, and whether they suffer from distortion. However, the measurement can’t tell the actual sound quality, which relies more on the driver quality.

What is the high-frequency response?

High-frequency response is the measurement of treble frequencies. It shows how a headphone reproduces frequencies from 4.000Hz to 20.000Hz.

Looking at the high-frequency response, you learn if headphones have a good extension in the highs and if they have a dark, bright, or even fatiguing treble.

What is the low or bass frequency response?

Low or bass frequency response is the measurement of the lower frequencies. It tells you how much headphones boost or reduce frequencies between 20Hz and 250Hz.

The bass frequency response reveals:

• How punchy headphones are
• How well they extend into sub-bass
• Whether they bleed into the midrange

What is the midrange frequency response?

Midrange frequency response is the measurement of mid-frequencies ranging from 250Hz to 4.000Hz.

Measurement of this range tells you how accurately headphones reproduce vocals and instruments, how full they sound, and if they’re harsh or honky, or thin and muted.

Frequency Response Chart

Frequency response charts are usually separated into sub-sections. We separated the audible frequency ranges into 9 sub-ranges, but it depends on who you ask.

Some add more ranges, some less, some might even call them differently. The point of separating it into smaller bits is to accurately explain the changes in the response.

How do you analyze frequency response?

Frequency response measurement is represented with a line from 20Hz to 20.000Hz on the X axis.

Sometimes, it comes with a dotted line that represents a neutral response. In our measurements, you can get a neutral target response by drawing a horizontal line through 300Hz.

When you have both the frequency response measurement and a neutral target and know which part of the response is bass, midrange, and treble, you can compare them and observe differences.

Learn more in our article on how to read frequency response graphs.

The difference between frequency response and frequency spectrum

The difference between frequency response and spectrum is that the first shows the range (and energy) of frequencies a headphone can reproduce. The second shows frequencies’ energy (or loudness) in an audio recording.

You get the audio frequency response from headphones or speakers.

But you get an audio frequency spectrum from a recording when you, for example, import it into a recording software like Audacity. With the software, you can see which parts of the song are loud or quiet.

How Frequency Response Affects Music

To know how frequency response affects how you hear vocals and instruments, you must first understand their frequency response.

Every sound, whether it is a pluck of a string or a singer’s voice, has the primary frequency, which is the loudest, and a bunch of quieter harmonic frequencies extending left and right on the frequency range.

If the primary frequency or tone gives loudness, harmonic frequencies provide fullness and coloration. That’s why, ideally, you need neutral-sounding headphones to reproduce sounds in music faithfully.

However, hardly any headphone has a perfectly flat response. The majority have an altered frequency response that changes how the music sounds.

• Some have more energy in low frequencies, giving you louder bass, more rumble, and stronger punch.
• Some have more energy in the midrange, pushing vocals and instruments upfront and making them louder.
• Furthermore, some boost the treble for crisper, more detailed sound, but also more fatiguing to listen to for extended periods.

How frequency response affects sound quality

Frequency response affects sound quality by boosting specific frequencies that mask neighboring frequencies and make them impossible to hear.

While frequency response measurement doesn’t necessarily show sound quality, it can reveal some more significant issues with sound.

For example, if you see a bass boost curve extending over 250Hz into mids territory, you can assume the sound is muddy and too warm.

Or, if you see the most significant spike at 8-9kHz in treble, you can expect harsher sound and lack of detail (since many cheaper headphones boost that area to compensate for poor upper treble resolution).

How frequency response impacts clarity

Clarity primarily designates in higher frequencies. You can expect good clarity if the response is neutral or slightly boosted between 4.000Hz to 10.000Hz.

Note that dips around 9.000Hz are desirable and common in audiophile headphones. This region is often harsh and adds an unnatural shimmer to the sound.

Headphones compensate for that dip with a stronger upper treble, which adds air and resolution.

How frequency response affects music production

Music production requires you to use audio equipment with a neutral or flat frequency response.

You need a natural tonality of sound in the mix. Because you want the final mix to sound good on other headphones.

• For example, if you use bassy headphones to master your recording, you would reduce lower frequencies so they don’t sound bloated. However, someone listening to your recording with headphones with a relatively flat frequency response will end up hearing little to no bass.

Why are frequency response measurements important?

Frequency response measurements are important since they show you how headphones sound and expose any potential flaws in the response (like big spikes or dips).

Measurements can help you decide whether you want to continue with a purchase.

The best is to find third-party measurements, as the manufacturers always claim their headphones sound like the “Gods have made them”.

How to use equalizers and filters

There are many tricks you can use when dealing with equalizers. You can either:

• Tweak it yourself based on your sound preference.
• Find a frequency response measurement and lower the peaks and raise the dip with the EQ (you can leave the 8-9kHz dip if you see one).
• Find neutral EQ settings online (like in our reviews) and then modify the sound to match your taste.

Keep in mind that the sound slightly changes depending on your ear’s shape. Some frequency ranges resonate differently in your ear canals which impacts the sound. Find your resonant frequency by:

1. Downloading a frequency generator app.
2. Slowly play frequencies from 4kHz to 8kHz. Somewhere in between, you should hear a noticeable increase in loudness.
3. When applying EQ, try to lower the resonant region and observe if it makes the sound more pleasant.

Filters, on the other hand, filter out the electrical background noise that occurs when the signal travels from your device to your headphones.

However, most audio devices nowadays don’t suffer from audible background noise unless you crank up the volume. Buying a dedicated DAC or denoiser doesn’t make sense for a casual user.

The effect of frequency response on headphones and speakers

The frequency response of your headphones and speakers can alter how the music sounds if it isn’t completely flat.

• Ideally, the frequency response should be flat. This way, you hear precisely what a sound engineer heard when mastering the song you’re listening to.

Any deviation from a flat response will change the way that song sounds. Bassy headphones add more bass, brighter ones add treble, and so on.

However, the truth is no sound traveling from your headphones to your ears is perfectly flat. Even if they are tuned flat.

Sound encounters all sorts of obstacles along its way, causing it to reverberate, amplify, and mute. Even your ear canal can boost some frequencies differently from the ear canal of your friend.

That’s why you can only hear a close interpretation of the original recording. It would be challenging to hear it precisely as the artist intended to.

Understanding Audio Frequency Response

Before trying to understand frequency response measurements, it is good to know a little about what frequencies are and how they become the sound you hear.

We measure sound waves (or frequencies) in hertz (Hz). You can image sound waves as a series of peaks and dips. The frequency value depends on the number of “peaks and dips” in one second.

The higher the value of the hertz (or the higher the frequency), the more AB points (peaks and dips) you get in one second.

Furthermore, the bigger the arch (or the amplitude), the louder the sound.

Now let’s talk about sound waves. They travel by vibrating the air molecules (although sound can also travel through other things, like metal and bones).

These mechanical vibrations go into your ear canal and vibrate your eardrum. After vibrations go through the middle ear, they end in the cochlea, where they agitate tiny hairs.

Those tiny hair convert the mechanical (analog) vibrations into an electrical signal, which your brains interpret as sound. You can find a more detailed explanation here.

Frequency response in headphones is measured between 20Hz and 20.000Hz because that’s our hearing limit. That said, you can still feel frequencies below 20Hz.

On the other hand, only newborns can hear up to 20.000Hz. With age, hearing slowly deteriorates, either naturally or due to noise-induced hearing loss.

Is flat frequency response better than Harman curve?

Flat audio frequency response is ideal for professional audio work, whereas the Harman curve is better suited for music listening.

A flat or neutral response is ideal for audio reproduction and critical listening. However, to humans, it doesn’t sound very natural. It can be pretty dull, actually.

As discussed above, when traveling from point A to point B, the sound bounces around and reverberates; some frequencies boost, and some reduce. That also happens in sound-treated rooms like professional studios.

However, people found that “imperfect” sound to be more pleasing and natural to listen to since we also live and are familiar with a world where sound bounces around and changes response.

That’s why sound engineers try to find different frequency tunings to simulate the “natural sound” we all enjoy. The Harman frequency response curve is one of those tunings.

Thus, what is better is purely subjective. But for a casual user, the Harman curve sounds much more pleasing.

Common Misconceptions about Audio Frequency Response

It’s nothing wrong with having a slightly altered frequency response in your headphones.

However, you must know that if you go too far with the boost, the sound and your listening experience might suffer because of it.

Boosting high-frequency response is not always better

Knowing that treble adds clarity and sharpens the detail, you might feel the urge to boost high frequencies or buy headphones with a bright sound signature.

A little bit of boost in the treble doesn’t hurt, but remember that bright headphones are often fatiguing to listen to for extended periods.

• Brighter headphones are better geared for audio monitoring and other kinds of professional work where you want to analyze the sound and detect flaws.

Boosting low-frequency, bass response is not always better

A bass boost can make the sound more fun and punchy, which nicely compliments some music genres like electronic, hip-hop, and pop.

However, lower frequencies pack the most energy, so they easily overshadow the rest of the sound. Also, the larger the boost, the harder it is for the driver to maintain controlled bass.

In severe cases, drivers or speakers can’t handle the boost, and they start to distort.

A flat (neutral) frequency response is not always ideal

Perfectly flat sound can be quite dull as people don’t live in a perfectly flat world. Also, every person has sound preferences. Some like more bass, some more treble, and so on.

There are many reasons why that’s the case. Firstly, throughout your life, when buying budget headphones or attending a concert, you’re constantly bombarded with loud bass and treble.

That’s why most people consider a V-shaped response the most likable and everything else dull.

Secondly, our brains are quick to adapt to changes in sound. Even if your new headphones sound strange at first, you get used to them after a few listening sessions.

So, you might be listening to extremely bassy and muddy headphones and think they sound great. That’s normal; it happened to us as well.

That said, if you can, try to adapt to more balanced-sounding headphones. They will sound strange at first, but after a while, you will start noticing sounds and details you haven’t heard before.

Frequently Asked Questions (FAQ)

Conclusion

These are the essentials you need to know to understand audio frequency response. The key takeaway is to:

• Know what different frequency regions do.
• Be able to read a frequency response measurement.
• Understand how to use an audio equalizer to tweak the sound of your headphones.

Hopefully, you’ve learned something new. If you’re ready for the next step: Here’s how to make your headphones and earbuds sound better.

Peter Susic

From a childhood fascination with sound, Peter’s passion has evolved into a relentless pursuit of the finest headphones. He’s an audio expert with over 5 years of experience in testing both audiophile and consumer-grade headphones. Quote: “After many years, I can confidently tell which headphones are good and which are terrible.” Find his honest opinion in his reviews.