Sennheiser PXC 550
Sennheiser PXC 550     Sennheiser looks to have been imbibing some Parrot juice, delivering here a pair of Bluetooth noise-cancelling headphones loaded with Zik-like features that not so long ago the company might have considered gimmickery — effects modes, spoken status alerts, touchpad controls, and wild EQ options via an accompanying app for iOS and Android. All this complexity is not assisted by a pictorial quick start guide which is difficult to follow, because the captions are positioned closer to the wrong pictures than the right ones. We had trouble, for example, working out why the headphones were already powered up when we took them out of the box, until we untangled the caption juxtaposition issue and found that powering up occurs when you pivot the headshells from flat to operating position.
Clever? Well yes, in that it’s easy to turn them off when you put them down, though it happens whether you mean to or not. Often. 
This is also a design which over-uses voice prompts, a pet dislike for us — they even announce when they’re powering down, though given the pivoting headshell turn-off method, you couldn’t possibly be wearing the headphones at the time. 
Their fit will be dependent on your ear-size; their earpads are comfortable but strangely small, so that while the PXC 550 is nominally an overear design, the aperture was too small to accommodate our whole rear ear unless tucked inside. 
The labels on the right earshell buttons are teeny-tiny, but on close inspection under bright lights one button has a little music note on it, and this turned out to control the ‘effect mode’, shuttling through ‘Club’, ‘Movie’, ‘Speech’, and finally ‘Off’, each announced in turn not by the nicely spoken lady who turned your headphones on and off, but by a voice with a curious choice of Kate Moss-like Cockney accent, so that you might expect the announcement ‘Effects Mode – Club’ to be followed by a Dick van Dyke-like ‘Owlright Mary Poppins’. 
This button also controls call enhancement when making a call using the integrated microphones. 
Sennheiser PXC 550  The other visible control is a three-position slider for noise-cancelling, offering 0 (off), I (on) or II — this last being adaptive, varying the amount of NC depending on the level of noise. 
There is a third button to turn Bluetooth on and off — this is rather strangely hidden under the right hinge, so you likely won’t find it when looking for it, though you certainly won’t accidently use it when wearing them.  
So off we went, but there was a false start. ‘No device found’ announced the better-spoken of the two lady announcers into our ears, and this was mutual from our iPod touch, which couldn’t see the PXC 550s under its Bluetooth settings (it probably didn’t help that while handling the headphones we kept turning them off accidentally as one earcup or the other pivoted flat). They can pair via NFC, but for other devices it turns out you don’t put them in pairing mode using the Bluetooth button, which might seem sensible — instead they only pair if you press that ‘effects mode’ button for four seconds. How obvious!
The sound
Unusually unintuitive, then, poorly labelled, a confusing quick start guide — we were having trouble believing this was a Sennheiser product… until we started them playing. They redeem themselves entirely in their sound performance, which is both rich and accurate, and remarkably consistent whether noise-cancelling was on or off. Spoken word was given richness without overemphasis, podcasts were highly enjoyable and, unlike the Bose QC35s, you can turn off the NC if the mild suck-out feeling gets uncomfortable. They are beautifully musical, with usefully mild bass emphasis, a lovely midrange which serves both male and female vocals to near perfection, and a treble that may not extend into airy sparkle territory but is highly satisfying in portraying detail and ambience entirely in keeping with the overall sound balance.  And the ultralow bass on Neil Young’s ‘Walk With Me’ came through  as a big resonant bass guitar, not merely crazy bass blur, a perfect result. 
The emotive strings of ‘Gabriel’s Oboe’ from ‘The Mission’ soundtrack did the hair-raising thing as they built, our favourite Mozart symphony (K183) didn’t get its full dynamics or airy heights delivered but was nothing but enjoyable in warmth of tone. The PXC 550 represents another excellent and musical Sennheiser performance from a Bluetooth connection.
Those modes — ‘Club’ well overemphasises the bass, ‘Movie’ massively overemphasises bass, ‘Speech’ puts everything into a boxy midrange, and ‘Off’ brings it all nice again. Choice is good, we guess, but since Sennheiser gets sound balance so excellently spot-on to start with, why offer so many ways to spoil the engineers’ work? We would avoid this button entirely. 
Those earpad controls paused our music if we so much as brushed the earcup (putting an arm behind our head, or repositioning things to get our ear back inside etc), and often paused as we were raising or lowering volume when swiping; we much preferred the straightforward volume control on the Bose QC35s. You can make this activity even more virulent by activating SmartPause in the app; they then pause when you take them off too.
We assumed that tapping the earpad twice would move forward a track, as per the increasingly universal implementation of inline controls, but no, two taps activates Talk Through, which usefully pauses the music and feeds the external mike through, so you can converse without removing the PXC 550s. For track forward and back you slide sideways on the earpad; this did work flawlessly. 
Sennheiser PXC 550  The app 
There’s an app to go with these headphones — it’s called CapTune (there’s another CapTune app, for a music video community, but Sennheiser’s is clearly labelled). It offers far more extensive EQ, including an eight-step preference-building ‘SoundCheck’, though this only operates on music played through the Sennheiser app itself (not, for example, from an iPhone’s own Music app). Through the app you can access on-device music, including playlists, and Tidal, but that’s currently all. The SoundCheck procedure offers eight steps each offering a pair of possible EQ curves (see screenshots left) — you choose A, B or flat on a track of your choice, and can store the result. For us, not a single A or B curve was preferable to the flat response, so this was really presenting 16 more ways to muck up the excellent original balance of the PXC 550s. Again, we say no! You can mess with parametric sliders too, if you want to alter the sound that way instead.
More usefully you can change the language of voice prompts and (cue choirs of angels singing hallelujah) turn voice prompts off altogether. Aside from this, and the SmartPause function, CapTune is an app that primarily gets in the way of high quality music reproduction.  
Cable playback (an unusual right-ear connection) sounds even better than Bluetooth, with more level available, the bass just a little hot, but that can be useful on a noisy commute even with the NC available to drop the background noise. The volume earpad sliding and effects modes still operate, also the two-tap Talk Through, but transport controls shift to the inline lozenge on the cable, which reverts to the usual two-taps-for-next-track system. Much better.
As a nice bonus, these can also playback via USB from a computer while charging. 
Familiarity will aid enjoyment of the PXC 550s. The controls are unintuitive to a new user, but if you digest the full manual they certainly deliver an excellent sound. Play with the many EQ options, but always compare the results with flat performance, because we thought that was by far the best sound. And they fold into a wonderfully compact carrycase. But really, throughout this review, we were screaming KISS KISS KISS — Keep It Simple, Stupid. If Sennheiser could strip out a lot of the gubbins and thereby deliver these headphones $100 cheaper, say, it would be an excellent call. 
Sennheiser PXC 550