Early last month, Sennheiser revealed a successor to the highly-regarded – but now quite old – PXC 450 noise-canceling travel headphones. The stylish PXC 550s come with an integrated rechargeable battery instead of two AAA-sized replaceables, touch panel control to replace the physical buttons and Bluetooth wireless capabilities to give the mobile business users they're aimed at a choice of connectivity options. The German audio house isn't the only company looking to get its high-end wireless over-ears onto the heads of business class travelers, so is the promise of high quality sound, proprietary active noise cancellation and long-haul battery performance enough to guarantee a place in carry on luggage? We've spent a few weeks roaming around to find out.

The PXC 550 headphones come in a D-shaped fabric travel pouch, with supplied cables and adapters tucked away inside, and a multi-language quick start guide. Though we found this guide to be sufficient to get us up and running, we'd recommend downloading the full user manual to get the most of the headphones.

The circumaural closed back headphones are a tasteful mix of stainless steel, matte black plastic and soft PU leatherette, and hinges at either end of the headband allow them to be collapsed down for transport. We found the shaped pads offered a snug fit around the ears, which is particularly important for noise-canceling headphones, though folks with large ears might struggle to tuck them in comfortably.

The headphone circuitry is activated by twisting each earcup, from travel mode through 90 degrees to ready for wearing – a voice prompt kindly confirms that the PXC 550s have been powered on. Though the rotating joints do look and feel solid enough, we did wonder whether this could prove the weak point in the design as far as long term use or rough, on-the-road handling is concerned.

"Sennheiser is known for the high reliability and durability of our products – and the PXC 550 Wireless is no exception," a company rep told us. "Before our products are brought to market, they are subject to a range of tests to ensure excellent durability of every function and the longevity of the product."

Putting the brakes on background noise

The active noise-canceling technology at the heart of the PXC550s is called NoiseGard, which was initially developed for Lufthansa pilots in the 1980s and first released to consumers in 1992. The current flavor uses four pick-up microphones – two inside and two outside – and is reported capable of wiping out up to 30 dB of ambient noise, allowing for a more immersive listening experience or just a way to cut out enough of the background din to get some shut-eye.

"The two microphones with openings to the outside of the headset work in the Feed-Forward ANC system to reduce noise at the ear for the high frequency spectrum, while the additional two microphones inside the headset in the Feed-Back ANC system reduce noise at the ear in the low frequency spectrum," explained Sennheiser. "The result of this combination is a broad reduction in ambient noise covering from both low frequency (eg. engine rumble) to higher frequency noise (eg. air-condition systems) up to 30 dB of total noise attenuation."

A switch about half way up the rear edge of the right earphone housing is used to engage NoiseGard. The lower-most position if off, followed by adaptive noise cancellation and then up once more for maximum attenuation of ambient noise. The over-ear design does provide some isolation from ambient noises beyond the cups when NoiseGard is inactive, but pushing the switch up a notch makes the private listening cocoon even better.

In use, the NoiseGard tech did an excellent job of blocking out the unwelcome rumble of a car or bus rolling along the road, a train trundling down the tracks while packed with sun-seeking holiday makers and the constant whine of the jet engines of the A320 taking us to our next trade show.

The tortuous roar of our Dyson vacuum cleaner was also reduced to a breezy whimper, the grumble of the air conditioning units in our local consumer electronics shop disappeared completely and walking through traffic-heavy streets proved less thunderous.

The headphones did reduce, but didn't completely block, the chatter of passengers or the piercing screams of bored kids during peak hour train journeys, though when music was played at a comfortable listening level, such things were only really noticeable during pauses or very quiet moments.

Wireless wandering

The Bluetooth 4.2 technology is activated using a switch top front on the right earcup, and offers a wireless range of about 10 meters (33 ft), depending on such things as the thickness of walls between the source device and headphones. When wearing the headphones or when folded flat for storage, this switch is hidden under the arm, and revealed by tipping the earcup forward at the top.

The PXC 550s are also NFC-capable for quick connect, and boast aptX codec support for "CD quality" wireless playback potential (though a good number of source devices don't support this technology). Pairing via Bluetooth search and NFC proved pain-free, and the connection profiles of up to eight devices are saved for reconnect ease.

The travel headphones come supplied with an audio cable with inline remote, for listening to a non-Bluetooth player or when having to go into airplane mode while traveling – the Bluetooth circuitry is immediately deactivated when the audio cable is plugged in.

When cabled to a music source and with Sennheiser's NoiseGard hybrid noise cancellation engaged, the built-in 3.7 VDC, 700 mAh Li-Pol battery is reported to offer around 30 hours of playback for every 3 hours on charge over USB. Interesting side note: music can be routed through the USB cable while charging, allowing files at up to 16-bit/48 kHz resolution to be played.

Sennheiser promises over 20 hours when listening wirelessly with NoiseGard activated. We actually got around 22 - 23 hours during cable-free ANC stop/start music sessions, which is pretty impressive. As of writing, we're coming up to 30 hours of non-continuous cabled listening with a little voice prompt telling us that we still have over 20 percent of battery life remaining. Again, color us impressed.

The touchy subject of control

The outer egg-shaped face of the right earphone housing is home to a touch-enabled control surface. A single tap starts or stops music playback on a Bluetooth-connected source device, swiping forward and backward skips tracks and volume level is increased by pushing a finger up vertically. A voice prompt tells you when max level is reached.

The touch surface is also used to take calls via three beamforming microphones. A double tap accepts a call, a long press rejects it and a swipe mutes/unmutes. On the few occasions when music playback was interrupted by the need to make or take a call, the person on the other end of the "line" reported that my voice came through loud and clear, and I found the audio quality through the headphones to be far superior than when just having a smartphone resting against my ear.

Above an LED battery status indicator to the rear of the right earcup is a button for scrolling through EQ fx presets. There's one to add a little more lower end, another tailored for movie audio and a third for enhancing the spoken word. The final option is off.

The Club mode doesn't produce nearly enough extra bass to smack down Beats, but proved welcome when listening to 70s funk, fast-paced metal and driven rock. Movie fx mode dials in a touch of reverb, opens up the audio image and boosts the lower registers. Because activating the Speech setting really messed with the mix, making much of our sample music sound terrible, it was tempting to only dial it in when listening to audio books or podcasts. But flipping the switch for acoustic tracks like Ciel by Eric Johnson or Highway Man from The Damned and the Dirty brought some extra sparkle to the unplugged six-string.

Another feature we found very useful was TalkThrough. Rather than having to remove the headphones when a friend wants to chat, or at least reluctantly lifting an earcup, a quick double tap on the control surface pauses the audio when in Bluetooth mode (or mutes the music when cabled) and activates the microphones so you can hear what's being said as though you aren't wearing any headphones. And it worked very well indeed

Fine tuning? There's an app for that

Though the PXC 550s work just fine straight out of the box, Sennheiser gives users the opportunity to customize and optimize the listening experience via a free mobile app for iOS/Android. CapTune has its own built-in music player that can be used with any headphones or the host smartphone/tablet speakers. But when connected to the PCX 550s over Bluetooth, more is on offer.

In addition to giving us a choice of nine EQ presets or the ability to set up our own custom option, the app also allowed us to add an extra EQ fx mode to those already cooked into the headphones. The Director setting can be used to dial in the rumble, add some tasty reverb and spatial effects. Music streaming services like Tidal can also be played from within the app.

The level of active noise cancellation when in adaptive ANC mode can be adjusted from within the app, and Smart Pause can be activated. The latter auto pauses playback when the headphones are removed from the head or when a call is received.

Elsewhere, other functions like altering the voice prompts or turning them off completely, enabling/disabling the Call Enhancement feature and viewing actual remaining battery life of the headphones (rather than the rough LED status/voice prompt estimates) all help to make the app well worth downloading.

Time to face the music

There's little point in stuffing headphones to bursting point with fancy, whizz-bang technology if they sound rubbish and are uncomfortable to wear. Happily the PXC 550s don't fall through either of those trapdoors.

Sennheiser's new travelers sport the same SYS 32 dynamic drivers as used in the Momentum 2.0 headphones, with a frequency response of 17 Hz - 23 kHz, less than 0.5 percent total harmonic distortion, 110 dB SPL and what the company describes as a balanced sound signature. We'd say the delivery will suit modern ears looking for something a little more musical than reference headphones, with enough attention to detail to satisfy classical music lovers and modern audiophiles alike.

There was a welcome depth and authority to Sonny Landreth's Elemental Journey (MP3) streamed over Bluetooth, for example, and a warmness to the sound of glass on metal that less capable wireless headphones can miss. Swapping instrumentals for powerful vocal harmonies, it was a similar story for Atom Bomb by the Blind Boys of Alabama (MP3 over Bluetooth), with aptX support on our Note 8.0 treating us to pleasantly rich and full-bodied gospel tones.

Sticking with Bluetooth, but replacing lossy MP3s with a CD loaded into a laptop, we didn't detect any discernible loss of sonic detail when playing a CD of Paganini's Violin Concertos in the hands of Salvatore Accardo. The PXC 550s somehow managed to draw out instrument detail that even top performers like V-Moda's Crossfade Wireless headphones can miss. And with the Director EQ fx mode set to extend the spatial effect, the orchestra was given even more room to excel.

We've spent a good while cabled to the living room hi-fi, too, where the impressive detail lent an in your face quality to Neil Fallon's throaty growl and an in-the-room feel to instruments on a vinyl spin of Psychic Warfare by Clutch. We'd say that the PXC 550s offer enough to low end impact to satisfy most modern tastes, though nowhere near enough for Beats lovers, which isn't necessarily a bad thing. And if you're looking to wallow in deep mud or bask in sonic boom, you'll need to look elsewhere. The bass is tight and funky.

The PXC 550s were totally unfazed by adding extra musicians to the stage, when a CD of Cicada from Hazmat Modine was popped in the hi-fi, for example. There was a pleasant richness to the sassy brass, a healthy dose of vitality and punch to the rhythm section, lots of air to the tuba bass and no uncomfortable sharpness to the high frequency percussion. Vocals remained well defined in the mix, even when faced with some stiff competition from instruments in the same frequency range.

Travel headphones are not just for listening to music while globetrotting of course, many folks use tablets – and even smartphones – to watch movies and rerun TV favorites. Even with the EQ fx disabled, the audio of DVD and stored content was well balanced, detailed and clear. Audio track quality of online entertainment can vary widely from source to source, but the app's movie EQ mode did help in this regard – making the mediocre more bearable and bringing a bit more depth and spatial spread to higher quality audio.

At 227 g (8 oz), the PXC 550s felt very light on the head, with little to no marathon session top of the head pain being registered. There was no pinching either and the ear pads proved to be very comfortable against the head, though during long-haul sessions our ears did get quite toasty. And even with some quite enthusiastic head-bopping to the speed-driven grind of Motörhead, the PXC 550s stayed put.

When used with the CapTune music player on the Note 8.0, the volume range was greater than when we played music through the stock Android player or USB Audio Player Pro – topping out at an only-just-bearable listening level. Max volume turned out to be a fairly low distortion affair, only really starting to creep in a tad at the upper reaches of CapTune-assisted playback.

When the output was rocking at its loudest, I asked a few commuters if the PXC 550s leaked any music their way. Only those standing uncomfortably close could detect a little music escaping from the confines of the earpads during lulls in ambient noise. And they were quite surprised by just how loud the caterwaul thundering down my ear canals actually was.

The bottom line

When we covered the launch of the PXC 550 headphones last month, we called them Sennheiser's response to the release of the QC35s from Bose, the latter forcing us to seriously reconsider our relationship with Sennheiser's excellent Momentum 2.0 Wireless cans.

Cards on the table – the NoiseGard circuitry active in the PXC 550s simply doesn't hold a candle to the market-leading Bose tech. Sennheiser's ANC is good, just not Bose good. We do prefer Sennheiser's sound signature though, and when excellent sonic clarity and detail, battery performance, touch panel control and the CapTune app are added to the equation, the Sennheiser offering is an impressive all-round package that's hard not to like.

In fact, the PXC 550s are among the very best Bluetooth headphones we've tried, but at a suggested retail price of US$399.95, they are a little more expensive than the QC35s. They're about on par for wireless ANC circumaurals from Parrot and Denon, however, and about 50 bucks cheaper than Bang & Olufsen's premium cans.

Sennheiser's latest travel companions are available now. Have a look at the promo video below.

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