With a close proximity in price and an origin with brands well-regarded for audiophile-quality products, the Sennheiser HD600 and the HiFiMan HE400i seem perfectly poised to compete.  While both are open-back models, the Sennheiser model utilizes a dynamic driver design, while the HiFiMan uses the less-common planar magnetic design.  And while both share certain similarities, there are an equal number of differences.

Sennheiser HD600

Build Quality

Where build quality is concerned, both of these headphones hold up well.  The HD600 features a plastic headband and earcups with aluminum extenders and velour padding.  The cable is of a standard Y design, with a removable connector at each earcup.  The 3-meter cable terminates in a 3.5mm stereo plug that fits a snug 1/4” adapter.  The HE400i also uses a substantial amout of plastic in the earcups, while the extenders are part of a larger bar that arch over the wearers head, holding a suspension-style pleather band.  The earcups feature a pleather casing with a velour surface resting against the wearer’s head.  The HE400i also features a Y cable design, with the two 2.5mm connectors for the earcups and a 1/4” adapter available for the normal 3.5mm stereo plug at the other end of the 1.5-meter cable.

Both headphones give a strong impression of quality.  The Sennheiser HD600, by virtue of it’s stylish blue-ish marble-y plastic exterior, may win in the Looks Category.  However, the less-rigid feel of the HiFiMan HE400i can give one the impression of being a more high-end set of ‘phones.  The cable is twice as long on the HD600 as it is on the 400i – and since we don’t see much need for such a short cable on a pair of open back headphones, we’ll give Sennheiser the point on this one.

Winner:  HD600

Comfort

With velour padding a tight headband, the HD600 isn’t a totally uncomfortable headphone.  There’s a bit of give and swivel on either earcup and the whole thing sits securely on my head.  There’s some slight pressure from the cups and the band – not something that would suck when compared to most other headphones, but when stacked up against the HE400i, it does seem a little less optimal.  The HE400i, thanks to that rather flexible suspension-style headband, sits on your head like a dream.  The fact that the HE400i’s earcups also rotate a complete 180 degrees also helps in this regard.

Winner:  HE400i

HiFiMan HE400i (old version with screw-in connectors)

Design

The Sennheiser HD600 features a frequency range of 12-40500 hertz and a nominal impedance of 300 ohms.  As previously noted, it features a dynamic driver design and is open-back.  In theory this would lend itself to a high-power setup where a user could hear a wide range of detail, without much muffled sound.  It would also allow for a very realistic sense of space within music.  The HE400i, by contrast, offers a frequency range of 20-35000 hertz and a nominal impedance of 35 ohms.  It is of the planar magnetic design and is also open-back.  This design is noted for imparting greater bass detail and would (in theory) work well with both low- and high-powered setups.  Some planar magnetic headphones require significant damping which can lead to a more muffled sound, especially in the mids and highs.

Both headphones have their pros and cons on this point, and objectively stated (without a true impression of sound), it would be stupid to attach any worth to which one boasts the better specifications.  Compared to other headphones with the same designs, both are seen as capable performers in their own classes, so we’ll leave it at that.

Winner:  Both

Sound

The HD600 sounds fairly clean with some slight compression, and a decent level of detail throughout, but particularly in the mids and highs.  Bass is rich and full, but not necessarily full of detail.  The HE400i picks up the slack here, and delivers much much more bass detail (exactly as we suspected, what with the planar magnetic design and all).  Where the HE400i might falter is in its offering of overall detail, which seems just a little less comprehensive, and this headphone doesn’t compete as well with the HD600 when it comes to mids and highs.  However, the sound still seems a little more articulate and sharper in attack than the Sennheiser.

Winner: HE400i

By no means is one headphone necessarily inferior to the other.  When people ask me what headphones are best, I usually tell them “Different strokes for different folks.”  It all depends on what you’re looking for.  In many respects, all headphones are equal.  And these two headphones are so damn close to one another that either one would probably justify the costs.  But I’ve seen a lot of people asking for a comparison between these two headphones, and my boss told me to come up with some comparison reviews, so voila! some fodder about how one awesome headphone is subjectively better that another awesome headphone.  For those seeking more detailed bass in a comfortable package, look no further than the HE400i.  For those seeking something a little more middle-of-the-road, the HD600 offers some great performance (and usually at a lower price-point, too).