Okay, I’ll admit the title of this post is a little click-baity, because I’m not going to tell you which set of headphones is better. I am going to tell you about the factors that make them different from each other, and hopefully that information will help you make a wise decision when you go looking for a new pair of really damn good cans.
Because these ARE both really good headphones.
The big deal about these new Audeze headphones are that they are “[t]he world’s first on-ear planar magnetic” headphones. First, we need to unpack the tech-speak there. Turns out, there isn’t just one technology for headphones these days. This entry at Wikipedia will give you many of the details, but rather than the traditional moving-coil technology common to most speakers and headphones (including the Sennheisers), the Audeze Sines use a membrane with wires embedded in it, suspended between two oppositely-poled magnets. This is supposed to deliver more detailed sound, and indeed many of the more expensive audiophile-grade headphones on the market use this technology (or something even weirder). Which is why having this tech in a pair of sub-$500 headphones is a big deal.
I’ve spent quite a few hours listening to both pairs of headphones, and here’s the thing: the sound coming out of each of these it so good, and so similar, that the choice between them comes down to non-aural issues. Sonically, they both deliver highly-detailed sound; picking out separate instruments in orchestral pieces is a no-brainer, and even hearing the musicians taking breaths or moving pages is easy. They’re both pretty darn neutral, meaning if you’re listening to them without any equalizer (EQ) fiddling, there’s no part of the scale that stands out more than the other. These aren’t bass-thumpers by themselves, though if you’re running them through a DAC like I was, you can add your own personal boosts. They both produce sound that feels clean, and just slightly warm (which I like). The only significant difference I could hear was, when I added some boost on the higher end, the Sines picked up more of the hiss inherent in the recording I was listening to. Which really meant it probably didn’t need as much EQ on the high end.
So, since they’re very comparable when it comes to just the sound, how are they different? That comes down to their two main physical differences: on-ear versus over-the-ear, and closed-back versus open-back (the Sines are the first, in each case).
The Sines, being closed-back headphones, are more intimate. When you listen to music with them, you are hearing a concert just for you, inside your own cocoon. They keep exterior sounds out to a large extent (being on-ear helps there are well), so they are good for listening outdoors, on on a bus or plane, where you want to minimize outside noise and just enjoy your tunes. The negative to this are that your ears will build up a bit of heat, such that long-term listening can get a little oppressive after a while.
The Sennheisers are open-backed, meaning you aren’t shut off from the rest of the world. That means they’re not good for noisy environments, or for places where you don’t want what you’re listening to to be overheard. However, the benefit here is a much wider soundstage. Where the Sines make you feel like you’re getting a private concert in a cocoon, the open-back Sennheisers make it feel like your sitting in a chair in the middle of the orchestra on stage at the concert hall. The sound is bigger; and your ears will stay cooler as well.
Other minor notes: the Sines are about 20% heavier than the Sennheisers. They feel sturdier, like a higher-end product. But they do sit heavier on your head, and were a bit tight on my rather large noggin. The Sines are better designed for mobility, folding up smaller. They also come with an optional lightning cable so you can listen to them straight from your iPhone. What’s special about the cable is that it includes a built-in DAC, taking advantage of the iPhone’s ability to deliver high-quality digital files directly, and allowing for users to customize their sound via app. This is a pretty big value-add.
The bottom line for me is that I’ll keep listening to my Sennheisers when I’m plugged in at home, in a reasonably quiet environment, because I can wear them comfortably for extended periods. But if I were going to be traveling, I’d grab a pair of Audeze Sines. They sound every bit as good, but keep the noisy world outside, are much easier to pack, and feel like they’d survive the trip easily. If I could have (and afford) both, I’d be a pretty happy listener.
The Sennheiser HD6XX were a special limited-edition run from Massdrop, and are not currently available (though they may come back). However, they are pretty much exactly the same as the Sennheiser HD650, which you can find at Amazon for $316.
All equipment in this review was either purchased by me, or on loan from the manufacturer.