Technology Explained

10 Terms You Should Know to Identify the Best Headphones

Andy Betts 19-08-2015

There are so many different brands, styles and prices of headphone that it can be very difficult to find a pair that is right for you.


You might be wary of the trend for celebrity-endorsed headphones, but browsing the spec sheet doesn’t make things any easier. Headphone specs are complex, and very technical, and sometimes don’t even have any meaningful effect on sound quality.

In this guide we’ll cut through the jargon and show you what the key headphone specifications actually mean, and why — or if — they matter.

1. In-ear

In-ear (canal) headphones, also known in-ear monitors, sit directly inside the ear canal. They have two main technical benefits. They sit closer to the ear drum, so can deliver excellent sound quality, and they also fill the entrance to the ear, so are effective at sealing out external noise.

grado headphones

In-ear headphones come with a selection of different sized tips so you can find one that fits your ear canal. Getting the right fit is essential for attaining best performance; using a wrong-sized tip will affect audio isolation and the earphones will be prone to falling out.


In-ear headphones are extremely portable, so are most convenient for use on the go, or at the gym How To Workout Without Going To The Gym It's hard enough setting aside time for actual exercise, but throw in your commute and it can add up to a lot of wasted time. Try these effective workouts without ever leaving your home. Read More . Their smaller size, however, means they cannot compare in all-round performance to a larger set.

2. On-ear

On-ear headphones, also called supra-aural headphones, rest on top of the ear. Like in-ear headphones, they direct sound straight down the ear canal, but don’t seal out external noises, and may also leak noise to those sat nearby.

We Are The Rhoads Client: Bose

Many find them more comfortable than earbuds, and they are less likely to trap heat on your ears than over-ear headphones are. “Clamping” can be an issue, though, where they squeeze too tightly and become uncomfortable with extended use. It’s important to find a pair that fits well.


On-ear headphones are a good compromise solution, with excellent sound quality (in higher end sets) and a good level of portability.

3. Over-ear

Over-ear or circumaural headphones encase the entire ear. Their increased size makes room for a larger driver, with louder volume and better bass performance. The driver is also positioned further away from the ear, producing a more spacious sound akin to what you hear from speakers.

beats over ear

By covering the ear, these headphones offer good noise isolation, but they are a lot less portable than the other formats.


Although it is no longer true to say that over-ear headphones are automatically better than other styles, circumaural headphones remain the audiophiles’ choice.

Open and closed back

You’ll also see headphones (over-ear ones especially) described as being either “open back” or “closed back”. This refers to whether the back of the earcups are open or sealed.

“Closed back” headphones offer better noise isolation, and tend to have a more forceful sound similar to what you get from in-ear headphones. “Open back” headphones have more sound leakage and let in more ambient noise, but deliver what audiophiles often describe as a more natural sound.

4. Drivers

The driver is the most important component in a pair of headphones. It turns an electrical signal into sound pressure — in other words, it creates the sound.


There are different types of driver, but they all consist primarily of magnets, voice coils and a diaphragm. The components cause the diaphragm to vibrate, and these vibrations produce sound waves that our ears interpret as sound.

apple drivers

On the headphone spec sheet, the Driver indicates the diameter of the diaphragm, measured in millimeters. As a general rule (but not always true), the larger the driver, the better the sound, especially for bass performance. On over-ear headphones, a driver of 40mm or larger is a good bet.

Since in-ear headphones cannot fit a large driver, a growing number take a dual-driver approach. Rather than having a single driver handling the entire frequency range, there’s one specifically for bass and another for the mid and high frequencies.

5. Sensitivity and Sound Pressure Level

Sensitivity and Sound Pressure Level (SPL) are related terms, and either may be used on headphone spec sheets. They indicate how loud the headphones will go.

headphone specs

Sensitivity shows how efficiently an electrical signal is converted into an acoustic signal. SPL is how sensitivity is measured, and is often displayed as decibels of SPL per milliwatt (although there is no absolute standard for this).

Most headphones are within the range of 85-120 dB SPL/mW. To provide some context, regular city traffic is around 80dB, a shouting voice 105dB, and a jet taking off 130dB.

The pain threshold for noise is thought to be around 120dB, while the Occupational Safety and Health Administration warns of the dangers of hearing loss with prolonged exposure to an SPL of more than 85dB.

6. Impedance

Impedance is a measure of electrical resistance and is displayed in Ohms (?). In the simplest terms, higher impedance means more resistance, which means more power is needed to drive the headphones.

Headphones designed for mobile devices tend to have lower impedance (below 32?), so they use less power. High-end and pro-quality headphones have very high impedance (300? or more), and require a dedicated amplifier to power them.

The downside to lower impedance headphones is that, while they use a lower voltage, they require a higher current. An electrical current creates vibration, which in turn creates sound. The result is that lower impedance headphones may emit an audible background hiss.

Impedance mismatch can also cause this and other performance issues. Mismatch can occur when using high impedance headphones with a smartphone, or low impedance headphones with a high-end audio system. It’s important to have the right type of headphones for the audio equipment you are using.

7. Frequency Response

Frequency response indicates the range of audio frequencies the headphones can reproduce. It’s measured in Hertz, with the lowest number representing the amount of bass, and the highest treble. Most headphones have a stated frequency response of around 20-20,000Hz, which matches that of human hearing.

The numbers are not really a good indicator of sound quality, though they can help you choose the right headphones for a particular type of music. For instance, if you want lots of bass, then you should look for headphones that support a low bass frequency.

8. Total Harmonic Distortion

Total harmonic distortion (THD) shows the level of distortion there may be when using headphones at a high volume.

As we’ve seen, headphones produce sound via a vibrating diaphragm in the driver. At high volumes, the diaphragm may not be able to vibrate fast enough, resulting in distortion. THD is expressed as a percentage, and lower is better. Most headphones have a THD of less than 1%, and high-end sets considerably less.

9. Noise Cancellation

Noise-cancelling headphones have embedded microphones and electronic chips. They record ambient noise, then create an inverse sound wave and feed it back into the headphones to effectively cancel out the sound. And they’re one of the best office gadgets to aid your creativity.

It works best for constant, low frequencies, and is less effective for mid-range frequencies and above. So, if you’re on a flight, you may find engine noise is reduced, but not the sound of the crying baby in the seat in front.

Noise cancellation requires battery power. Its effectiveness can vary considerably from one headset model to the next. For more on how noise-canceling headphones work How Do Noise-Cancelling Headphones Work? Want to get the most from your music collection? Noise cancelling headphones are a good option, but how do they work? Read More , check out our guide.

10. Noise Isolation

Noise isolating headphones physically block external sounds. This is either with over-ear, closed-back headphones encasing the entire ear, or, more effectively, in-ear headphones sealing the ear canal.

ultimate ears

In this respect, in-ear headphones work like earplugs, and it is important that you get the tightest possible seal by using the correct sized eartips.

Noise isolation is passive – doesn’t require an external power supply – and isn’t limited to certain frequencies. It also tends to appear in more affordable headphones than noise cancellation technology.

Understanding Headphone Specs

Headphone specifications are a surprisingly complicated business, and you need a good grasp of physics, electronics, and math to be able to really drill down into what they mean. Even then, the simple fact is that you cannot discern the quality of a pair of headphones just by a series of numbers on a spec sheet.

And don’t be discouraged when you encounter new terms and specs we haven’t mentioned above. For example, did you know about bone conducting headphones The 5 Best Bone Conduction Headphones Bone conduction headphones keep you to comfortable stay connected to the outside world. Here are the best bone conduction headphones available today. Read More ?

You can use specs to narrow down your choice, and identify those that suit your favorite style of music, the environment you’re using them in, and the audio gear you’re using them with. Once you’ve done that, you should check reviews and user reports to find out exactly how well they perform.

Interested in headphones for working out? Check out the best wireless sports headphones The 7 Best Wireless Sport Headphones The best wireless sports headphones let you enjoy music in the gym or while exercising outside. Here are several great options. Read More . If you’d rather go for a wired option, try these top wired headphones The Best Wired Headphones 2019 Looking for the best wired headphones? Here are our favorite options, ranging from ultra-budget to high-end! Read More . And if you’re looking for a cheaper solution, check out our recommendations for the best cheap headphones The Best Cheap Headphones You Can Actually Afford Cheap headphones worth your money can be hard to find. We've rounded up the best cheap headphones for every occasion. Read More . Finally, we have a compilation of the best headphones for kids The 9 Best Headphones for Kids Some headphones are designed with smaller ears in mind. So, here's our rundown of the best kids headphones available today. Read More .

Image credits: Grado in-ear headphones via Jonathan Grado, Beats over-ear via Fofarama, Apple drivers via, Ultimate Ears via Nan Palmero

Related topics: Buying Tips, Headphones.

Affiliate Disclosure: By buying the products we recommend, you help keep the site alive. Read more.

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  1. Ayush kumar
    October 25, 2019 at 5:02 pm

    This article is to the point and informative, great piece of work.

  2. Rosie Beckett
    November 14, 2018 at 5:20 pm

    I am in charge of getting new headphones for the computers in my fifth-grade classroom and I did not realize there are so many considerations and options to choose from! It is interesting that you say over-ear headphones are great for noise-cancellation and are typically not as portable as other options. This would actually be a great benefit for my classroom because this way my students are less likely to take the headphones away from the computer and lose them.

  3. Amzadvali
    October 18, 2017 at 1:09 pm


  4. Nikhilesh Dabhi
    July 31, 2017 at 12:16 pm

    can you tell me the specs of skull candy xtPlyo and what to choose between sony MDR XB510AS and skullcandy xtPlyo

  5. noel
    June 8, 2017 at 5:57 pm

    I found one headphone which has Closed ear, 50mm drivers, 10-25khz frequency,
    32impedance, 1/8 to 1/4 gold platted adapter.

    So I wanna know is it a good headphone for studio for such genre as EDM in bass,beat clear sound.

  6. DjPhase
    September 21, 2016 at 1:46 pm


    What I would like to see from headphone manufacturers is specs related to the mainstream music genres. So, I I listen to EDM or Hip Hop, I would like to know which headphones would be preferrable for this AND differentiate between casual listening and DJing.

  7. Anonymous
    August 16, 2016 at 3:41 pm

    Meant to say which over ear headphones do I need for iPhone app pain.2. Thanks

  8. Anonymous
    August 16, 2016 at 3:37 pm

    Overear for iPhone app pain.2

  9. Amtej Bhullar
    May 9, 2016 at 5:16 pm

    Im looking for headphones that are good for a lot of bass, and i will probably listening to hip hop and rap, with decent bass. Price doesn't matter. What headphones do you reccomend

    • JW
      December 17, 2016 at 8:12 am

      You should probably look at skullcandy crusher!

    • Dylan
      August 27, 2017 at 4:44 pm

      I know this is old, but I thought I'd give my input. I just recently got a pair of Sennheiser HD6 Mix headphones, paid $180 after getting an extra 2 year full warranty, and they sound absolutely amazing, and the bass response is insane. Before these I had a pair of $100 AudioTechnicas, and I'd say they were the best headphones I'd ever had up to that point. In comparison, they suck. If you're looking for another set of headphones, I'd definitely recommend the HD6 Mix.

  10. K8
    April 19, 2016 at 2:23 pm

    I'm looking for closed back fair isolation headphones for voice recording. Fit comfortably snug on small head.
    small head.

  11. Anonymous
    August 19, 2015 at 10:25 pm

    So then, if I'm looking for a headphone with the best audio quality, what should I be looking for?

    • Anonymous
      August 20, 2015 at 1:42 pm

      What's Your Budget?

      • Anonymous
        August 20, 2015 at 10:07 pm

        Preferably, under $700

    • Jackson Chung
      August 21, 2015 at 10:56 am

      It depends on what you'll be using it for.

    • Anonymous
      August 22, 2015 at 2:37 am

      I just listen to music but wanted a better quality.

      • Jackson Chung
        August 25, 2015 at 11:26 am

        No one can tell you "the best headphones" without knowing your preference for open/closed back, around/on/in-ear style and budget.

        • Anonymous
          August 26, 2015 at 10:50 pm

          I thought those preferences are for style. I wanted to have an in-ear headphone and not over $300

    • Chax
      September 2, 2016 at 11:00 pm

      Low total harmonic distortion and flat frequency/phase response.

  12. Anonymous
    August 19, 2015 at 8:01 pm

    Thank you for this. The clarification is helpful.