There are three different types. There is the neckband type (such as the Sennheiser Momentum In-Ear Wireless), and the cabled type, which has a single cable between each IEM (such as the Sennheiser Momentum Wireless Free). 

But for those who need the ultimate in portability, we have the third category, considered 'True Wireless'. With no cables at all, these IEMs are completely free and unhindered. They are often bundled with a charging pouch or case, which allows for both easy storage and topping up the battery.

This style of headphone has been around for a while but enjoyed an increase in popularity when Apple released its Airpods. On the back of this, brands scrambled to create competing products that would be more suited to the discerning audio enthusiast.

Samsung gave it a crack with their Gear Icon X, a sports-oriented release which suffered nasty battery life and connection issues. After trying them out for a few months myself, I eventually returned my pair, losing hope that a decent true wireless IEM was even possible to produce. 

Until now ...

SENNHEISER

Momentum True Wireless In-Ear Monitors

£279.99

With the Momentum True Wireless IEMs, Sennheiser has eliminated the cables entirely and has put forward an audiophile alternative to the household Apple version of the wireless earbud: the Sennheiser Momentum True Wireless. 

Does this new release have what it takes to poke its way into the ever-expanding wireless IEMs market? 

Build

Straight out of the box, one thing is made abundantly and instantly clear: this isn’t just a run of the mill wireless earphone. There are no cables, no wires, nothing. Unlike the Apple Airpods, these sit inside the listener's ear. Despite being relatively small and lightweight, these are absolutely packed with tech.

The IEMs are stored in a small case which is wrapped in an Alcantara-like fabric which has been so well designed and crafted, that it feels like it really should be housing expensive jewellery. 

Upon opening the lid of the case, the two IEMs are revealed; snugly perched into perfectly cut holes, they are firmly latched onto their charging pins with snap-in magnets. Thanks to this magnetic system, the IEMs are easy to remove from the case and even easier to put back in. Another example of German engineering at its finest. 

The IEMs themselves are satin black with bold silver faceplates bearing the Sennheiser logo. Due to their relatively small size, they don’t look ridiculous when being worn in the ears. According to Sennheiser, they're also splash resistant.

Aesthetically, everything about the Momentum True Wireless is stunning. From the classy looking case to the IEMs themselves, every single detail has been well thought out, and I honestly can’t fault them at all. They look and feel superb.  

Internals

Inside each unit are a 7mm single dynamic full-range driver, a microphone, and a metallic touch panel on the outside for user interaction. 

Using AAC/APTX/APTX Low Latency codecs, the IEMs will automatically decide which is best for your source device upon connecting. 

The storage case contains a 12-hour battery (which gives the IEMs around 4 hours of juice per use) and is charged via USB-C. It’s worth noting that this is the first Sennheiser product I’ve seen which accepts USB-C, and I’d love to see more of this in future. 

Without NFC, the pairing process is a fairly standard Bluetooth affair. Once the pairing process is complete, they have no trouble at all picking up a fast and reliable connection. 

In Use

One thing I need to emphasise straight away: these IEMs are remarkably intuitive to use. Just open the case, place them in your ears and tap the left side. This sends a “resume” command to your smartphone, and you can go about your merry way instantly. When you reach your destination, just put them back into the case which will pause your track and switch them off. Easy!

Despite all the technology built into each earpiece, they are surprisingly small and lightweight, and even after lengthy sessions (including watching full movies), I had no comfort issues at all.

The True Wireless IEMs have more bulk compared to the other Momentum in-ear wireless offerings, but this also gives them an edge on the isolation front as well. Thankfully, this added bulk didn’t make them heavy or unwieldy. 

They can be used in one-ear mode, but puzzlingly this can only be the right ear. Removing the left ear will cause them to switch off.

To control volume, press your finger against either the left or right unit. Tapping the right ear will activate Siri or Google Assistant (depending on your smartphone model). 

I had no significant complaints from call recipients when I was using the Momentum True Wireless as a hands-free device. However, one or two callers did note that I sounded a  little quieter compared to using just a phone.

My favourite part of using these IEMs in day to day use is the “Transparent Hearing” feature. Simply double tap the right ear, and all outside noise is allowed in via the built-in microphone. I’ve tried this feature on other brand headphones before, and it has been hit-or-miss. However, I would call it “almost perfect” on these and in use, I can almost forget I’m wearing IEMs at all. Very cool.

Smart Control App

Sennheiser also has a Smart control app which allows your smartphone to controls the IEMs directly. It features a built-in EQ system which updates immediately upon making adjustments, and stores the EQ setting within the IEM itself. It might a very basic (non-parametric) EQ, but it's still a very cool feature to add.

The app will also give you information about battery life, transparent sound settings, and let you adjust phone call settings and the like. It took a bit of fiddling to get it talking to the IEMs but overall is a great inclusion.

Sound

A fantastic test track to wake up the Momentum 7mm drivers is Wir by Stephan Bodzin. The track starts off with some upbeat, heavy midbass kicks, which are delivered by the IEMs with plenty of body and slam. Around 40 seconds in, the haunting synthesised samples start floating through the track, demonstrating a surprisingly detailed and airy soundstage for a single driver dynamic IEM. 

Speaking of surprising, for a large IEM enclosure which carries with it a battery and Bluetooth technology, I expected these to sound slow and sluggish as a result. I was wrong. The sharp stabs of Stephan’s custom-made synthesisers are presented with reverb tails, which shows off the lightning fast and accurate decay of these drivers. The sheer speed and dynamic nature of these drivers are showcased perfectly, especially when all of the electronic layers mesh together at the 3:20 mark.

To take a step in a slightly unusual direction, I decided to listen to the unique stylings of Animosity by Johnny Rain and James Blake. This track marries up the unusual combination of generic 2018 rap music with the eerie Radiohead-esque stylings of James Blake. The bass slams in the first minute of the song highlighting the power of the low end of these IEMs in the 30-100hz range. They can move substantial amounts of air when required. After the 2:00 mark, the rest of the song is peppered in gentle waves with both distant and upfront vocals, with plenty of tucked away details. With the older Momentum In-Ear Wireless, this section of the song is a little shrill and harsh, but this peak seems to have been tamed with the newer True Wireless format, despite keeping a fairly similar signature overall. 

I’m also happy to report that the only audible hiss I heard while using these was when the “Transparent Hearing” feature was switched on. In normal listening modes, these were as quiet as a mouse.

Conclusion

After using Sennheiser's Momentum True Wireless for two weeks, there is no doubt that this is the best product I’ve tested all year. They're a zero compromise In-Ear Monitor, which isn’t held back by the fact that it’s a wireless product. It offers a fantastic feature set, terrific battery life, and stunning looks. They are remarkably intuitive to use, all while delivering powerful, detailed and fast sound, with a programmable EQ to boot. 

I never thought I could feel so strongly about a Bluetooth audio product, but it's finally happened. 

Without hesitation, I put forward this review with the stamp of a StereoNET Applause Award, and give my strong recommendation for Product of the Year. I love it. 

For more information visit Sennheiser.

Manufacturer's Specs

• Dimensions- 78.6 x 45 x 35 mm (charging case)
• Microphone- MEMS
• Bluetooth Version- Bluetooth 5.0 compliant, class 1
• Supported Profiles- A2DP, AVRCP, HSP, HFP
• THD, total harmonic distortion - <0,08% (1kHz / 94dB)
• Ear coupling- Ear Canal
• Weight - 69.8 g (earbuds and charging case), 13.2 g (both earbuds), 56.6 g (charging case)
• Charging time - Approx. 1.5 hrs
• Frequency range - 5 Hz to 21 kHz (earbuds), 100 Hz to 10 kHz (microphone)
• Sensitivity - 107 dB SPL (1 kHz / 1 mW)
• Speaker type - Dynamic
• Battery time- Up to 4 hrs (A2DP) with rechargeable batteries of the earbuds, Up to 12 hrs with a rechargeable battery of the charging case
• Water Protection Code - IPX4, splash resistant (earbuds)
• Type of Codec - SBC, aptX™, aptX™ Low Latency, AAC