Sennheiser HD 820 Headphones Review

The Sennheiser HD 820 look similar to the HD 800 S but have different, closed-back ear cups. The headband and yokes are essentially the same, although the HD820 has slightly thicker hinges, most likely to better support the slightly denser ear cups. The ear cups have the same overall shape as the 800 S', but they are a bit denser and thicker with gorilla glass backplates that let you see the dynamic drivers inside. They look great, and most audiophiles and critical listeners will love the cool glass back design. However, like the open-back 800 S, they may be a little too bulky for some listeners, and even though they are closed-back headphones, they're not made to be used outdoors with your mobile phone but will look great sitting next to an amp in your listening room or on your office desk.

The Sennheiser HD 820 are comfortable but a little bulky. Their ear cups are the same size as that of the Sennheiser HD 800 S, which will be a bit too large for some listeners. You may feel slight gaps in the fit around your ears which may a bit bothersome, but on the upside, the cups are exceedingly well padded and very spacious. They have thicker and softer pads than the HD 800 S which feel slightly more comfortable and somewhat helps with the seal issues. The headband isn't as well padded as the ear cups but since it's fairly wide and the HD 820 overall are surprisingly lightweight for their size, you do not feel the absence of padding much. You can easily wear the HD 820 for hours at a time and not feel any fatigue.

These are critical listening headphones that do not come with any control schemes.

The Sennheiser HD 820 are fairly breathable and have large, spacious ear cups. However, since they are closed-back headphones, they will make your ears a lot warmer than the HD 800 S. On the upside, the ear cups are fairly large and do not always create the best seal around your ears, which does let a bit of air enter the closed-back enclosure and cool your ears. Unfortunately, they will not be as breathable as most open back headphones, on-ears, or in-ears so you may have to take a few breaks especially if you have really long listening sessions.

Like the Focal Elegia and most critical listening headphones, the Sennheiser HD 820 are not made to be very portable. They have some of the largest ear cups on any over-ear design that we've tested so far, and they do not fold or lay flat to make them easier to carry around in a case. This is to be expected though as most likely you will use your headphones in a dedicated listening room or at the office, but not out and about with your high-res audio player or with your phone.

Unfortunately, the Sennheiser HD 820 do not come with a dedicated case. Like the HD 800s, you can use the box that they are packaged in as a case but, it's more than double the size of the headphones and not practical to carry around unless you have a dedicated bag or suitcase. As expected though, these are not headphones that you will be carrying around often.

The Sennheiser HD 820, like the HD 800 S, have a good build quality that feels premium and well made. The ear cups are a mixture of dense plastic, metal and gorilla glass (for the see-through backplates). They look great and feel very high-end but less durable than some of the cheaper headsets we've reviewed. On the upside, the headband is also well made with a thin metal for support but plasticky yokes. The plastic does feel very durable and make the headset lighter than a solid metal frame but the yokes and swiveling hinges do not feel as durable as the rest of the design and are most likely the most susceptible parts of the HD 820. For even better built closed-back critical listening headphones, take a look at the Focal Stellia.

These headphones are not designed for use during sports or any physical activities. The ear cups have a large enough surface area that they will maintain their position during casual listening sessions even when tilting your head. However, they are not meant and will not be suitable for physical activity. Their cable is detachable but locks into the ear cups and will yank the headphones off your head or potentially damage the ear cups if violently removed.

• Sennheiser HD 820 Headphones
• 1/4" to 1/8" Adapter
• Audio cable (x2)
• Carrying pouch
• USB memory drive

The frequency response consistency of the Sennheiser HD 820 is sub-par. The bass delivery across our 5 human subjects was quite disappointing. The maximum deviation in bass response measured at 100Hz was more than 9dB, and at 20Hz more than 15dB. This is quite significant and noticeable. We noticed that not only wearing glasses could cause a big drop in bass, but people with different head shapes and sizes also experienced significantly different amount of bass. This is a big contrast to the very consistent bass of the HD 800 S and is probably due to the closed-back design and large ear cups, which left gaps around the narrower sides of the subjects' heads. On the plus side, their treble delivery is very consistent, even above 10KHz.

The bass is good. LFE (low-frequency extension) is at 10Hz, which is excellent. Also, low-bass, responsible for the thump and rumble common to bass-heavy tracks, is within 0.5dB of our neutral target. Mid-bass, responsible for the body of bass guitars and the punch of kick drums is also flat and within 0.7dB of our target. However, high-bass, responsible for warmth is overemphasized by about 2dB, making the overall bass of these headphones a bit muddy. It should be noted that this is the average bass response across 5 human subjects, and as you can see in the frequency response consistency section, the amount of bass delivered by these headphones can vary quite significantly from user to user.

The mid-range of the Sennheiser HD820 is decent. The overall response throughout the range is quite even, which is good. However, the dip in low-mid around 300Hz makes the vocals and lead instruments noticeably thin sounding. The wide bump across mid-mid and high-mid makes their mid-range noticeably prominent and forward, which brings the vocals and lead instruments to the front of the mix.

The treble is good. The overall response is decently even and well-balanced. The only remark here is the 5dB dip around 3.5KHz which will have a small but negative effect on the amount of detail and articulation of their sound. This will be mostly noticeable on vocals and lead instruments.

The imaging is great. Weighted group delay at 0.52, which is decent. However, the graph shows a deviation in group delay at 60Hz which is beyond the audibility threshold. This can result in a bass that is a little slow and loose around that frequency. The group delay performance in the mid and treble ranges is excellent. Additionally, the L/R drivers of our test unit were exceptionally well-matched in frequency, amplitude, and phase response, ensuring an accurate placement and localization of objects (voices, instruments, video game effects) in the stereo field.

The soundstage of the HD 820 is decent. Their PRTF response shows a decent amount of pinna activation and interaction, however, the accuracy of the interaction is not very high. They also have a closed-back enclosure. This and the low accuracy of their PRTF response make their soundstage less natural and open-sounding compared to open-back headphones like the HD 800 S. On the plus side, they have deep notch present at the 10KHz region which helps with moving the soundstage out of the listener's head, similar to that of the HD 800 S.

The isolation performance is average. Since these over-ear headphones don't have active noise cancelling, they do not achieve any isolation in the bass range. This means that they will let in all the low-frequency rumbles of airplane and bus engines. In the mid-range, important for blocking out speech, they provide more than 14dB of isolation, which is above-average. In the treble range, occupied by sharp sounds like S and Ts, they isolate by more than 32dB, which is good. Compared to the open-back HD 800 S, the HD 820 is noticeably more isolating.

The leakage performance is sub-par. Even thought these are closed-back headphones, they have a relatively loud and broad leakage partially due to their large drivers. However, they are significantly more quiet than their open-back counterpart, the HD 800 S. The significant portion of their leakage is between 300Hz and 6KHz, which is a broad range. This means their leakage will sound fuller than that of in-ears and earbuds. Also, the overall level of their leakage is relatively loud. With the music at 100dB SPL, their leakage at 1 foot away averages at 48dB SPL and peaks at 64dB SPL, which is noticeably louder than the noise floor of an average office.

The Sennheiser HD 820 do not come with a microphone. For a wired headphone with a good in-line microphone, check out the Bose SoundTrue Around-Ear II, the Bose QuietComfort 25 or the Apple EarPods.

These headphones do not have a microphone so the recording quality has not been tested.

The Sennheiser HD 820 do not have a microphone so the noise handling has not been tested.

These headphones do not have any active components and do not require a battery.

These headphones do not come with an app or software for added customization options.

These headphones are wired and do not have a Bluetooth connection. If you want a good-sounding wireless headset, then consider the Bose QuietComfort 35 II.

The wired connection of these headphones has negligible latency which is suitable for gaming and home-theater use.

They have a simple 1/4" TRS audio cable with no in-line remote/microphone, so they will only provide audio when connected to your PS4, Xbox One or PC.

The Sennheiser HD 820 do not have a dock. If you need a headset with a dock that also has a wired connection for gaming or watching movies, then consider the SteelSeries Arctis 7.