Sennheiser HD 820 review: The new benchmark for closed-back headphones

The HD 820 are the latest high-end headphones from German Hi-Fi specialists Sennheiser. They have a lot in common with the popular open-backed HD 800 and HD 800S models, but this time the company has chosen a closed-back design.

Here, the company’s new headphones have a glass panel, which by default, gives them better isolation and a better mid-bass presence This does, however, sacrifice the openness and clarity you’d find on open-back headphones. One such example comes in form of Sennheiser’s other flagship models, the HD 800 and HD 800S, which to many, are go-to reference headphones. The question is: has the German company set the bar too high with its previous iterations?

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Sennheiser HD 820 review: What you need to know

The Sennheiser HD 820 are arguably the best over-the-ear closed-back headphones to have ever existed. They’re as comfortable as the HD 800 and HD 800S, and they come with a convenient pack of three swappable 3.6m cables, terminating variously in a balanced 4.4mm plug, XLR connector and unbalanced 6.3mm jack.

But, while the HD 820’s excellent design and sound characteristics can’t be denied, their sound can’t quite drop jaws like their open-backed siblings. Whether they’re right for you or not will, therefore, depend on your priorities.

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Sennheiser HD 820 review: Price and competition

The HD 800 and HD 800S are expensive headphones, costing £1,100 and £1,400 respectively. The HD 820 raises the stakes even further, coming in at an eye-watering £2,000.

If you’re willing to spend more than a grand on a pair of headphones, there are several other flagship models to consider. The Fostex TH900 MkII at £1,150 and the Audeze LCD-XC at £1,600 are worthy closed-back rivals, while the Audeze LCD-3 at £1,600 and the Sony MDR-Z1R at £1,650 head up the open-backed competition. 

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Sennheiser HD 820 review: Build quality, comfort and isolation

The HD 820 are visibly reminiscent of the HD 800 line, but they feature a new all-black design and a concave glass pane over the back of each ear. That’s Corning Gorilla Glass, meaning you needn’t worry about scratches or accidental drops.

The glass cover has an effect on the sound, as I’ll discuss below, and it also provides much greater isolation than you’ll get from the HD 800 and HD 800S. It doesn’t match up to the isolation of the Fostex TH900 MkII or the Audeze LCD-XC, but there’s certainly a lot less leakage than with its open-backed siblings.

One area where the family resemblance is particularly strong is the comfort. Like the original HD 800, the HD 820 are a pleasure to wear, even for hours. I wore them on an extended gaming session and didn’t experience the slightest discomfort, even while wearing my reading glasses.

The plastic and metal headband sits very lightly on the head, with a lovely soft microfibre fabric on the top and around your ears. The pads are twice as thick as the ones on the HD 800S, so they clamp on a little more strongly and won’t fall off so easily when you’re headbanging to System of a Down.

The other notable design point is the proprietary connector on the outer edge of the headphones’ drivers, into which you plug your choice of detachable cable.

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Sennheiser HD 820 review: Sound quality

The HD 820 use a pair of 56mm dynamic drivers to deliver sound and have the same 300Ω impedance as their open-backed counterparts. I tested them with a wide variety of listening material, using the balanced XLR output on a Sennheiser HDV 820 headphone amp, and the sound was simply fantastic throughout the frequency range. I’d go as far as saying that these are among the most neutral-sounding closed-back headphones you can buy. Compared to the Fostex TH900 MkII and the Audeze LCD-XC, the HD 820 sound less bassy and better balanced, without an overly warm signature.

Even so, the HD820 can’t quite live up to the near-perfect mid-range reproduction of the open-backed HD 800 and HD 800S. By comparison, they sound a little restrained in the lower mids at around the 300Hz region, while the upper mids feel a little boosted. A 1KHz boost was particularly noticeable in Baby D’s Let Me Be Your Fantasy (Platform 16 Remix), in which the vocals are slightly overpowered by the instrumentation.

Similarly, bass is excellent on its own terms. The HD 820’s low end extends brilliantly, with a controlled and precise mid-bass shunt. It’s a very refined sound and a touch weightier than the HD 800 and HD 800S. Yet these drivers don’t provide the same level of excitement as other closed-back headphones. For example, the Fostex TH900 MkII’s Japanese cherry birch wooden cups provide a meaty sound to Chris Brown’s Loyal, while the HD 820 sound tame in comparison. If you enjoy a precise, heart-pounding bassline punch, I’d lean towards the Fostex.

One of the HD820’s strongest suits is its high-end reproduction. You’ll be rocking your head from side to side as you listen to Great Spirit by Armin van Buuren vs Vini Vici featuring Hilight Tribe. Like their open-back siblings, the HD 820 provide an exceptionally clean and crisp treble response that isn’t fatiguing for your ears – and there’s not a hint of the sibilance that afflicted the original HD 800.

For me, though, the HD 820’s most impressive trait is its soundstage reproduction. It’s wide and deep, thanks to those large drivers, and presents really excellent instrument separation. Positional cues in games are exceptional, while the instruments and vocals in Bruno Mars’ Locked Out Of Heaven were flawless. Naturally, the HD 800 and HD 800S sound even wider and airier – it’s what differentiates open-back and closed-back headphones – but the HD820 comes amazingly close for a closed-back design.

I also tested the HD820 with Chord’s Hugo 2 headphone amp, via an unbalanced 6.3mm connection, but this didn’t provide the same degree of detail as Sennheiser’s own offering. Clearly, like its predecessors, the HD 820 perform best when paired with the right amp and DAC.

Sennheiser HD 820 review: Verdict

The HD 820 deliver exactly what you’d expect from a closed-back variant of the HD 800S. They’re supremely comfortable, produce an impressively neutral sound and offer better isolation than their open-backed siblings. 

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Personally, I find myself gravitating back to the HD 800S for their cleaner mid-range reproduction or to the Fostex TH900 MkII for their meatier sound signature. But, if you’re looking for an excellent soundstage, near-flat sounding mids and some form of isolation from the outside world – and are willing to pay for the privilege – then you’ll struggle to find better than the Sennheiser HD 820.