On each side of the Sennheiser HD 700 there lies cause for raised expectations. Below it in price are the Sennheiser HD 650, extremely popular headphones with a bassy, dark sound and above it the HD 800 - which are some of the most intensely detailed-sounding headphones in the world.
True to form, the Sennheiser HD 700 fall somewhere in-between. These headphones are darker sounding and warmer than the bright-ish HD 800 and better-resolved and more detailed than 650s.
Having given Sennheiser a great many plaudits over the past year, part of us wanted to be able to announce it had finally mucked-up. That the HD 700 weren't worth the money, and aren't a patch on the HD 800. Sadly, we can't.
Superb balance and a smooth run from low bass to the top of the frequency spectrum give them a simply wonderful sound that makes them good for all-day listening. At our original preview during CES, there were points where we seemed to encounter some harshness, but we're yet to hear any with out review units. If anything, the warmer, darker sound makes them less tiring to listen to than the breathtaking HD 800.
Bass character is similar to the Sennheiser HD 800. It's lean and muscular, with plenty of attack and enough volume to lend excitement to tracks that rely on a pounding bass line. However, if you're upgrading from the HD 650 or other lower-end HD-series open-back headphones, you'll need to get used to the reduced level of bass on offer here. As a result, though, clarity is much, much improved - there is zero sense of mid-range muddling here.
The character of the sound is nevertheless on the dark side, which is one of the key things that differentiates these headphones from the HD 800. Well, that and the less-wide soundstage and overall lesser detail - although this should be viewed from the perspective that the Sennheiser HD 800 are the outliers in their field on both these fronts. These are still highly-detailed headphones with a wide sound that you'd expect given their open-back design.
To find out how they compare closer to their own field, we pitched them up against the Shure SRH1440 and HiFiMAN HE-5. They offer greater clarity and sonic integrity than the SRH1440, and perform on a similar level to the HE-5, but with greater warmth and thickness - perhaps not an entirely good thing, depending on your outlook.
However, they are also less warm and bassy than a great many Sennheiser headphones. We found this helped to get rid of the tendency to sound slightly dull, seen most recently in the otherwise-great Sennheiser RS 220.
With great mid and treble crispness, the texture of driving instruments like guitars and synths is rendered with great verve - they can and do sound exciting. As such, we prefer them to the lower-end models for rock music, much as you might assume their weightier bass might hand them the win. This same crispness does wonders for dialogue in films too.
Easy to drive?
The 6.3mm jack at the end of the HD 700 cable should be enough to tell you that these headphones are not there to be plugged into your MP3 player. Most of our testing was done with the basic Fiio E9 desktop amplifier and the more powerful HiFiMAN EF-5, but these headphones are not particularly hard to drive. At 150ohm impedance, they should in theory be easier to handle than the 300ohm Sennheiser HD 650.
Once you get into the land of serious headphones, the notion of value becomes hard to quantify. The best we can do is to compare the Sennheiser HD 700 to their rivals. They significantly outperform the Shure SRH1440, and are a definite upgrade over the Sennheiser HD 650. These aren't the magic headphone that manages to surpass all its more-expensive rivals, though - the Beyerdynamic T1 and Sennheiser HD 800 are better in several respects. However, they do deserve their place on shelves, even at the high price.
The Sennheiser HD 700 are serious £600 headphones that sit between the long-standing HD 650 and HD 800 models. Tonally, they sit somewhere in between too, melding the dark-leaning tone of the 650 with the more refined detailing and superior bass balance of the HD 800. If you want plenty of detail without a bright sound signature, they're an excellent choice.