Sennheiser HD 4.50 BTNC Wireless: In Your Sonic Bubble

23rd June 2017

Noise cancellation can often be a useful solution when wanting to listen to music in noisy environments. Paul Rigby reviews the latest in this burgeoning genre, the Sennheiser HD 4.50 BTNC Wireless headphones

This closed-back wireless headset features Sennheiser’s NoiseGard active noise cancellation (a system that was developed by the company) for mobile use in lively environments. How does it work? The company stated that, “Tiny microphones pick up low-frequency ambient noise near the ear. The NoiseGard electronics use this noise to generate a sound wave which is the exact opposite, the effect being that the polarity reversed signal cancels most of the outside noise.”

A wireless connection is made via either Bluetooth or NFC to connect the headphones to your mobile music source. Quite comfortable with a foldaway design for easy storage, the HD 4.50s let you enjoy NoiseGard-protected music for up to 19 hours on a single Li-ion Polymer battery charge (it lasts up to 25 hours with NoiseGard switched off).


Arriving with a carry case and a plug-in wire when wireless is not possible (plugging the cable into the chassis effectively turns off the active state of the headphones), the chassis includes integrated microphones, a power button, phone-related multi-function button, volume control, access for the headphone cable and USB port for charging.

An app can be downloaded for use with mobile phone and tablets from both iOS and Android devices. Called Captune, it offers a range of EQ settings and can be used a fully fledged music player.


I approached the testing of these headphones with a slight degree of trepidation. I find that active noise cancelling is a two way street in that it might stop noise entering upon the headphone’s soundstage but it can restrict dynamics too. Would these new headphones buck that trend?

I began by teaming up the 4.50s with the company’s own Flex 5000. After all, if you’re going to listen to headphones as part of a TV experience, the reason is often because you don’t want to disturb others in the same room or, indeed, have their chatter disturb you in terms of their sound leakage into your ears. To access the Flex 5000, I began testing the headphones in wired mode. That is, the headphone wire connected the headphones to the Flex’s wireless module. I accessed a music TV station and played Culture Club’s Karma Chameleon.


In this mode, the 4.50s lacked any bass character or form, with lower bass frequencies noticeable by their absence. The soundstage was pushed way back to provide an almost detached presence for the music with appeared to live in the midrange and treble areas only.

I then utilised the Bluetooth mode and connected the headphones to my iPhone 6S using the pairing button on the right ear cup without any Sennheiser app in control. Don’t try to pair a Bluetooth device with the cable still connected because the Bluetooth will not work in this mode.

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Once connected, a quick and simple process, I played an MP3 version of Marvin Gaye’s Mercy Mercy Me. Once again, bass was largely absent during play, with lower mids or upper bass being the best I could hope for. The lack of bass did damage the overall symmetry of the soundstage, of course, although midrange was detailed and didn’t intrude in a bright or strident fashion. In this mode, the mids were clear and open with enough instrumental separation to provide a clear playback. Moving to Paul McCartney’s My Very Good Friend The Milkman did provide good textural tracking of the mature McCartney vocal with a slight rasping successfully portrayed while the jazz-like (and largely bass-less) backing instruments such as piano, muted trumpet and acoustic guitar providing an attractively complex arrangement that gave the track a light and energetic presentation.

I then decided enough was enough and turned to the company’s Captune app, I realised where all the bass had gone: it was hidden in the app! Apart from acting as a music player, the app also gives you a selection of varying EQ types, eight in all plus a custom option so that you can save your own sound modified preference. Tapping on the EQ list brought out the previously hidden bass and a far more tonally balanced presentation which, depending on the music type (a bit of Nina Simone here, and U2 there), enhanced the overall enjoyment. The standard of sound quality was not as in depth or as rich as a pair of similar hi-fi-centric audiophile, wired headphones. The sense of midrange insight, clarity and bass impact was good via the 4.50s but never reached the heights of the similarly priced HD579s, for example. Then again, the 4.50s are not designed to connect to a hi-fi, they are mobile-centric. Even so, 4.50 use is limited as the best part of the sound quality comes from the app’s prodding which restricts the best use of the headphones to those devices which can power the headphones with the Captune app in harness. Hence, the headphones are best used with a smartphone or tablet as opposed to a general music player or DAC.

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As for the noise cancellation? Very good. Not absolute, mind you. I used the headphones next to a pretty loud hifi and the headphones were not 100% in rejecting external noise but they did a pretty good job. Shall we say around 90-95% of all noise was rejected? Depending on the type of noise being played outside of the headphones themselves. Pretty good for the price, especially as the headphones were able to continue to provide a decent degree of sound quality.


A neatly designed and easy to use pair of wireless headphones that requires iOS or Android to work at its best and, specifically, the Captune app to bring it to life and to arm the design with a swathe of useful EQ curves. Providing a good quality noise cancellation performance, for the price, the Sennheiser HD 4.50BTNC performs well as a mobile design.


Price: £170


GOOD: easy to use, good noise cancellation, admirable overall sound quality, compact

BAD: performance dependent on the Captune app



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