There's no denying it: the Sennheiser HD 800 is an iconic headphone.
When it debuted back in 2009, it was a seriously radical looking and sounding upgrade over Sennheiser's previous flagship model, the HD 650. The HD 800 is still in the line, along with the slightly revised HD 800S, and they're both open-back designs.
Now we have something new -- the HD 820. It's the first closed-back 800 series headphone, designed to block external noise better than the HD 800 and HD 800S. All three are very expensive headphones with a similar quality look and feel. They're built to last decades.
For the HD 820 review Sennheiser also sent along a HD 800S, and I'm glad they did! It didn't take long to discover the 800S and 820 sound more different than I expected. They look so similar and share the exact same 56mm ring radiator driver. Both are high-impedance 300 ohm designs, but the HD 820's concave Gorilla Glass covers seal out external noise. The covers also prevent the headphones from "leaking" sound to anyone nearby. By contrast the HD 800S is an open-back design that has a metal grille that lets in external noise, and people nearby can hear sound from the headphone.
One other noteworthy difference, the HD 820's ear pads are thicker than the HD 800S', so the HD 820 produce a better ear seal. This headphone's noise isolation from external sound isn't on par with other high-end closed-back headphones like the Audeze LCD XC or Sony MDR Z1R, however. Those two headphones noise blocking abilities handily exceed the HD 820's. On the other hand I found wearing glasses was more comfortable with the HD 820 than it was with the LCD XC or MDR Z1R.
The HD 820 comes with three sets of 11-foot (3.6-meter) long silver-clad OFC copper cables; one with a standard 6.3mm plug, another cable with a 4.4mm Pentaconn plug, and the third cable is equipped with a four-pin XLR plug. The last two cables are provided for use with balanced headphone amplifiers. The HD 820 comes packed in a beautiful storage case, Sennheiser's warranty runs to two years.
The Sennheiser HD 800, HD 800S, and HD 820 are all high-impedance headphones, so ideally you'll want to pair them with a good headphone amp. They are all hand-built in Germany. The HD 820 retails for $2,400, £1,999 an AU$3,500; the HD 800S is $1,700, £1,395 and AU$1,894; and the HD 800 is $1,400, £999 and AU$1,238.
I streamed standard and high-resolution music files via Tidal and Qobuz subscription services and listened via a digital converter and a Pass Labs HPA1 headphone amplifier. Sadly, I didn't have the HD 800 on hand for these comparisons.
Ernst Reijseger's Cave of Forgotten Dreams soundtrack album was recorded in a church with magnificent acoustics so it's loaded with real, not artificial, ambience. I could hear the instruments and choir's voices reflecting off the walls and ceiling over the HD 800S, but those spatial cues weren't as clear via the HD 820. Voices sound more natural, so it's more of a you-are-there experience over the HD 800S; the HD 820 forfeits some of that quality.
The HD 800S' treble is airier than the HD 820's, I think that's part of the reason why the HD 800S' soundstage feels more open and spacious than the HD 820. Then again, bright or harsh recordings can be irritating over the HD 800S, the HD 820 takes some of the edge those recordings. The HD 820's low-end is richer and fuller than the HD 800S.
So your taste in music and genres may influence which Sennheiser headphone sounds best to you. Acoustic or any quiet, well-recorded music is better suited to the HD 800S; loud rock, pop, and dance music worked better on the HD 820.
I next pulled out a set of Audeze LCD XC closed-back planar magnetic headphones ($1,799, £1,299, AU$2,599). They are larger and much heavier headphones, and they have a weightier tonal balance than the HD 820. The LCD XC really kicks butt; it's more rock and roll than the HD 820!
Still, the soundstage narrowed over the LCD XC, pulling the sound inside my head, but the LCD XC produced superior transparency and resolution than the HD 820. Thanks also in part to the LCD XC's superior noise isolation, it was easier to hear quieter details of my recordings, and the LCD XC's bass was considerably more powerful. On the upside, the HD 820 was a lot more comfortable than the LCD XC, and that counts for a lot.
Sony's flagship MDR-Z1R closed-back headphone ($2,300, £1,650, AU$2,399) is a much warmer and fuller sounding headphone than either Sennheiser. It also does a better job hushing external noise than the HD 820, and I'd credit the MDR Z1R's thicker, more enveloping ear pads for its superior quietude. The HD 820 sounds clearer, more vibrant, and more open and spacious than the MDR-Z1R.
The HD 820 may be a closed-back headphone, but due in part to its just so-so ear pad seal, this headphone doesn't do a great job hushing external noise. The MDR Z1R and LCD XC are both superior in that regard. The LCD XC's bass dexterity and potency exceed the HD 820's and Z1R's; the LCD XC is the most alive and transparent-sounding headphone of the three closed-backs in this review. Nice, but the HD 820 is the most comfortable to wear for extended periods of time. Sorry, but you just can't get stupendous bass, uber-transparency, wide-open soundstage, class-leading noise isolation, and ultimate comfort all in one headphone.
Then there's the matter of price: the HD 820 runs $2,400 in the US, while the HD 800S is $1,700. Is the HD 820 worth the extra $700? The HD 800S sounds better overall, but the HD 820 will still be the preferred option if you crave meatier bass, and/or you need to hush external noise.