Open-back vs Closed-back Headphones
Which one is best for you?
Over-ear, on-ear, earbuds and in-ear headphones, all have open-back variations that aim to deliver a more immersive listening experience. This is typically done by opening up the headphones' ear cups with vents, ports or a mesh grill so that the sound feels more natural and part of your environment. However, although openness provides a more spacious soundstage that feels closer to a stereo speaker set up in an ideal room than headphones on your head, it also increases leakage and lets a lot of ambient noise into your audio.
What are open back headphones? Open back headphones have an open design that allows ambient noise to seep into the ear cups. This typically creates a more immersive sound.
Who should buy open back headphones? Critical listeners who want an immersive and accurate representation of their audio. However, they usually lack a little bass and can only be used indoors or in isolated environments where leakage is not an issue.
What are closed back headphones? Headphones with a closed ear cup design that seals the ear and prevents sound from leaking or seeping into your audio.
Who should buy closed back headphones? Most listeners who want a versatile set of headphones to use outdoors and indoors. They also tend to have a deeper bass range and provide enough isolation to use in loud and quiet environments.
We compare open and closed-back headphones based on sound, leakage, noise isolation, and comfort.
|Open vs Closed Headphones||Correlation||Open||Closed|
Bass describes the deep and heavy tones in your music. It represents the low-end spectrum of frequency response and ranges from 20Hz to 250HZ.
Results: From our test results, the major difference in frequency response between open and closed headphones is with the bass range. Open headphones have a more difficult time producing the extended low-bass (sub-bass) that some closed headphones can achieve. This is due to the open design of the ear cups, which doesn't seal the ears within a contained compartment.
Typically this causes open headphones to have a roll-off in the lower frequencies that make their bass somewhat lacking and less powerful than most closed-back models. To fix that, some open models have planar magnetic drivers that have a deeper bass-range, but it still might not be enough for fans of bass-heavy music.
Soundstage describes the perceived space and environment of sound, as created by the headphones acoustics. This makes the audio you hear feel like it's coming from speakers in a room rather than headphones on your head.
Results: Soundstage is the main difference between open and closed headphones. By design, open headphones let in a lot of ambient noise so that the audio you're listening to feels like it's part of your environment, and not coming directly from the headphones on your ears. Leakage gives the listener the subtle ambiance of the room, and the openness of the headphones dictate how spacious the soundstage will feel.
This means, unlike closed headphones that have limited acoustic interaction with the objects and walls in your environment, open headphones encourage these subtle effects, which enhance sound quality and make it a more immersive listening experience. Some closed-back models attempt to provide a more spacious soundstage electronically, via app support and software presets. However, they still don't excite the acoustics of your surroundings like open-back headphones, which is significant when critically listening.
Leakage is the sound that escapes the ear cups or earbuds. Therefore, very leaky headphones require an isolated environment, to not disturb the people around you. However, leakage can sometimes be beneficial, as it helps create a more immersive listening experience.
Results: From our test results, regular, closed-back headphones aim to reduce as much leakage as possible, to keep what you're listening to private. Open, and semi-open headphones leak a lot, which allows some of the sounds that escape to bounce off the walls and objects in your environment, providing the subtle ambiance of your surroundings. This gives the sound quality a bit more of a speaker-in-a-room feel than just regular headphones on your head.
Unfortunately, this also means that open-back designs are not very practical to use as casual, everyday headphones. The leakage level needs to be quite high for you to notice the subtle effects it has on sound quality, which will distract anyone in your immediate vicinity.
Noise isolation refers to a headphones' ability to isolate you from the outside world by preventing ambient noise from seeping into your audio.
Results: Noise isolation for passive, closed-back headphones depends on the quality of the seal created in, on or around the listener's ears. This usually blocks a fair amount of high-frequency noise but may require additional noise-canceling to reduce the lower frequencies. However, even passively isolating, closed-back headphones block sufficient noise to give listeners the flexibility of listening to audio in loud environments.
Open headphones, on the other hand, are designed to let in as much of the room ambiance as possible. This gives the audio reproduction a more natural sound quality that feels like it's part of your environment. Unfortunately, this also means that open headphones are very sensitive to noise and not as practical to use in loud settings. Unless you listen to your audio in isolated environments, open headphones may not be versatile enough for you.
Comfort refers to a headphone’s ability to provide a physically pleasant listening experience. This means they shouldn't cause any soreness, pain or excess heat during extended listening sessions. However, comfort is subjective and does not have a strong correlation between open and closed headphones. A headphones' comfort level will depend more on your taste and preferences.
Results: Open and closed headphones could have very similar designs. Some manufacturers even offer the same models in both closed and open-back variations. Breathability is the most noticeable difference between open and closed headphones. This means that the other aspects of comfort will depend more on the materials used for the padding, the tightness of the headband, and the size of the ear cups or earbuds.
However, from the headphones we've tested, we've noticed that the open-back models were slightly more comfortable. Their open fit dissipates heat a bit better and makes wearing open headphones for long periods of time pleasant and less clammy. They also typically have larger, more spacious ear cups to further enhance soundstage, which translates into a better fit for most listeners.
Open-Back Headphones are ideal if you are looking to experience a more immersive audio reproduction that feels like it's part of your environment. These type of headphones are typically geared toward critical listeners or audiophiles who prefer a natural and neutral sound quality that imitates a good speaker set up in an ideal room. However, this also means that they're not the most practical headphones. They can't be used outdoors in loud, noisy environments like being on a metro or a bus. The leakage level is also an issue in quieter settings which can be distracting to those around you. Check our recommendations for the best open-back headphones.
Closed-Back Headphones are the most common variations for headphones. They're geared towards the average listener who wants a good listening experience in a versatile design that can be used in both loud and quiet environments. This means closed-back headphones are less likely to be distracting to those around you and will prevent the ambient noise of your surroundings from seeping into your audio. They also cater more to fans of bass than open-back models. However, they can't create a soundstage as immersive. They also can't replicate the subtle effects and ambiance of the room that significantly improve sound quality. Check our recommendations for the best closed-back headphones.
Questions & Answers
First of all, let me say that I mostly agree with the way your highly rigorous headphones tests are conducted. You are, by a large margin, the most scientific, data-driven headphone review website that the Web has to offer, and that is absolutely amazing. Keep up the good work!
That being said, I'm the nitpicky type… and while I fully agree with most of your metrics, especially your target frequency response curve which is based on the latest research (Sean Olive be praised), some of them leave me a bit… sceptical, to say the least.
Specifically, the section that worries me most is the "Soundstage" section. This statement in particular:
"This means, unlike closed headphones that have limited acoustic interaction with the objects and walls in your environment. Open headphones encourage these subtle effects, which enhance sound quality and make it a more immersive listening experience. [closed-back models] don't excite the acoustics of your surroundings like open-back headphones, which is significant when critically listening."
Do you have a citation for this? Because that's the first time I've heard such claims, and I am quite skeptical of them. Quick back-of-the-envelope calculations suggest that the leakage from even a very open pair of headphones is far, *far* too weak to produce audible reflections off the surrounding environment. (I arrived at a -40 dB figure for a reflection off a wall 1 meter away in the most optimistic scenario, a level that has been proved to be inaudible in a number of studies - the threshold is more like -20 dB. See Toole, Floyd E. "Sound reproduction: Loudspeakers and Rooms", chapter 6 "Reflections, Images and the Precedence Effect" for a good summary of the research on the perception of acoustic reflections.)
In fact, there is evidence to suggest that the perceived differences between open-back and closed-back headphones can be explained purely by differences in frequency response (e.g. open-back headphones typically have less bass). For example, one of Olive's AES papers, "A Virtual Headphone Listening Test Methodology" (51st AES conference, 2013) shows that it is possible to make open headphones sound like closed headphones (and vice-versa) simply by equalizing them to the frequency response of a target headphone. The results are quite convincing.
For these reasons, I hope you can understand that I'm not convinced that your "Soundstage" section conveys useful information. I don't believe the "Openness" and "Acoustic space excitation" metrics are perceptually meaningful; I'm having trouble understanding PRTF (isn't that redundant with your target curve?); and there doesn't seem to be much point in measuring crosstalk since all the headphones that you've measured show very low values for that metric, as one would expect.
So, if you could provide your references for your claim that the perceived differences between closed-back and open-back headphones are caused by acoustic interactions of the headphones with the listener's surroundings, I would be curious to peruse them. Thanks!
Thanks for your question. In general, we do agree that some of our tests are more theoretical than empirical. This is something we want to improve, however, this is also a relatively new field, and sometimes we had to come up with our own tests because we couldn't find something similar in the literature. So I'm going to briefly describe the theory behind our soundstage section, and we would be interested in hearing your thoughts on them.
The "gold standard" for our headphone sound measurements (i.e. a device that would get 10/10 in our Sound section) is "the perfect stereo system in the perfect room", whatever perfect means! So our headphones are measured against a theoretical perfect loudspeaker setup. For localization tests, our approach is to divide them into two: Soundstage and Imaging. Note that these are our definitions of soundstage and imaging, and others may have different definitions.
Imaging qualities are inherent to the audio content, the headphones have to 'reproduce' them rather than 'create' them. They determine how accurately the objects are positioned in the stereo image. In other words, the localization cues that are already in the music (ITDs and IIDs).
Soundstage qualities are not inherent to the audio content, the headphones have to 'create' them rather than 'reproduce' them. They determine whether the sound is perceived to be coming from inside or in front of the head, how open and spacious the soundstage is, how much the headphones acoustically interact with the environment, and how strong the phantom center is.
So basically the combination of HRTF, room/reverb effects and crosstalk is what we put under Soundstage. In other words: the difference between a pair of loudspeakers in a room and a pair of headphones. To test for these differences, we have developed 4 tests: PRTF, Openness, Acoustic Space Excitation, and Correlated Crosstalk.
The metric that we call PRTF (pinna-related transfer function), is derived by measuring the headphones on the dummy head, once with the pinna attached and once with the pinna removed (we have an extra ear with the pinna cut off specifically for this test). The difference between the two frequency response measurements is the PRTF. This result will be scored against our reference PRTF which was derived by measuring a loudspeaker with and without the pinna, in a simulated anechoic environment, more than a meter away, at 30 degrees in front. This shows how much of the FR at the DRP (eardrum) was created using the pinna. As you can imagine, in-ears do not interact with the pinna at all and therefore their two measurements are identical. On the other hand, the HD 800 S and the Edition X show the most interaction.
We do agree with you that this is not the best way of measuring the HRTF effects of a pair of headphones, since all the information we need is already in the impulse response (FR+Phase) and there's no real need for measuring the headphones without the pinna. But for that we would need to be able to isolate the HRTF information in the impulse response, and we don't know how easy that is to do. But this is something that has been on our radar for some time, since we know in-ears that simulate HRTF using DSP are just around the corner and we can't measure that with our current method.
Openness, which is the inverse of our isolation test, is there account for the subjective feeling of the music being part of the environment. We don't have research to backup our hypothesis, except for the listening tests that we have performed internally, and for us there was definitely a difference in the perceived openness and spaciousness of soundstage.
We also agree with you that the effects of Acoustic Space Excitation (i.e. the inverse of our leakage test) are very minimal, and in most cases barely perceptible. But we included it in the spirit of being thorough. That's why it's only 10% of the soundstage score. However, in our internal listening tests we have been able to detect it with very loud and very open headphones (e.g. Listen to loud percussive music on a pair of Grados and then walk in and out of a bathroom and see if you notice the bathroom reverb being mixed with the music).
Same for crosstalk. It's been included in the spirit of being thorough and true to our "gold standard". But we haven't measured a single headphone so far that produces any useful crosstalk.
Looking forward to your thoughts.
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