Sennheiser HDB 630 review

No matter how sophisticated the engineering behind wireless headphones, their wire-free performance is inherently bound by the Bluetooth technologies they, and the smartphone (or other audio source) they are used with, support.

Sennheiser recognises this, and with its latest flagship wireless noise-cancelling over-ears, the HDB 630, has sought to improve things. How? By bundling in a clever little accessory that blesses your phone (or other audio source) with the same high-quality Bluetooth codec the headphones themselves support.

It’s a simple yet ingenious idea that pays dividends. Allow us to explain…

Features

You see, every Bluetooth-toting audio source, such as a smartphone or laptop, supports one (SBC) or more Bluetooth codecs. In the context of wireless headphone listening, these are software formats that compress and encode/decode music so that it can be efficiently transmitted wirelessly from, say, a phone to wireless headphones.

The most efficient, highest-quality codecs – aptX Lossless, aptX Adaptive and LDAC – retain the audio signal best (albeit not perfectly) during this process, allowing more of your music to be heard, but they aren’t universally supported by audio sources and headphones alike.

For example, iPhones, the audio source of choice for many people using Bluetooth headphones, only support SBC and AAC, the most basic, compressed, ‘lossy’ codecs. Android phones typically fare better on this front, although many don’t support the full codec suite. The flagship Samsung Galaxy S25 Ultra in our best smartphones buying guide, for example, supports LDAC and ‘only’ standard aptX – not the superior aptX HD, Adaptive or Lossless codecs.

As for laptops and computers, Apple’s MacBooks don’t natively support aptX (like iPhones, they typically prioritise AAC) and only select Windows machines do.

Bearing in mind that both the device and headphones must support the same codec to benefit from its optimal transmission, you can understand that the scenario in which one lets the other down is common.

Finally, we get to Sennheiser’s solution. The HDB 630 bundle in a BTD 700 USB-C dongle that you simply plug into your device’s USB-C to give it aptX Adaptive superpowers.

Pop it into an iPhone 15, for example (older iPhones will need to use the Lightning-to-USB-C adaptor too), and you suddenly have a true aptX Adaptive handshake between it and the HDB 630. For audio transmission integrity, that’s far superior to the AAC one you would get between these devices otherwise.

The dongle is tiny – roughly the size of the top part of your finger – and upon being plugged in connects to the Sennheiser headphones automatically, with a solid white LED light indicating a successful connection, and a purple one displayed during music playback.

On an iPhone, the BTD 700 and HDB 630 both show as ‘Connected’ in the Bluetooth menu; on an Android phone, the dongle simply appears as a ‘USB’ device in the Bluetooth menu below the connected HDB 630.

You can check the quality of the signal path in the Sennheiser Smart Control Plus app’s settings (see the screenshot below). Here, you’ll want to ensure the ‘Audio mode priority’ is set to ‘Hi-Res 24bit/96kHz’.

Sound

The dongle proves a valuable accessory. When connected to an iPhone 16 and old Samsung Galaxy S21, upgrading their respective AAC and aptX connectivity with the headphones to aptX Adaptive, the presentation gains in clarity and solidity.

It’s a good advert for the Bluetooth technology, demonstrating that higher-quality codecs do make a difference with hardware that is revealing enough to highlight them.

Indeed, the HDB 630 are such examples of capable hardware. The headway they make over Sennheiser’s former wireless flagships, the Momentum Wireless 4, somewhat take us aback during our first comparison. The HDB 630 are miles ahead when it comes to detail, dynamic expression and refinement.

These are wonderfully smooth and natural sounding headphones, full of shape and dynamism across the frequency range, and we’re no more than a song into our playlist before we begin to suspect that the Award-winning Sony WH-1000XM6’s days at the top of the leaderboard could be limited.

That song is Christine And The Queen's Mountains (we met), a piano ballad about a yearning for a past relationship that’s never coming back, and the Sennheisers pull you into Héloïse Adelaïde Letissier’s vocal longing with an incredible amount of midrange texture and dynamic attention to her inflections.

The sparse piano notes drip with harmonics, while the percussive rhythmic pattern comes through with precision and purpose. Through the Sonys, the emotional impact is still there, but the presentation is that bit flatter, the percussion and vocal delivery less shapely and dynamic within a more compressed soundstage.

It’s a similar story with Bon Iver’s S P E Y S I D E: the Sonys capture the textures of the acoustic strings and rich vocal and ably track their dynamic variety, yet the Sennheisers' more emphatically pursue their rises and falls, telling you more about how the strings are plucked. The viola gliding through the middle is thrust more into the spotlight, too.

Their bigger canvas and the more precise placement of, and greater separation between, musical elements within it make the dense production of Public Service Broadcasting’s Spitfire more easily digestible, and that commitment to space and scale never comes at the expense of musical cohesion either.

Here, precision and analysis go hand in hand with drive and vigour, making for the most informative and entertaining sound we’ve heard from wireless headphones at this price.

Design & comfort

If the sceptic in you has been waiting for a ‘but’, it doesn’t come here. The HDB 630 adopt the design language of recent Sennheiser Momentums, defined by chunky, ovular earcups free of any decoration. They’re probably not far off what a primary school child would draw if given the task to draw headphones.

That may not sound particularly inspiring, and those looking for blingier headwear at this premium price range will undoubtedly be more impressed by the Bowers & Wilkins Px7 S3 and Apple AirPods Max. But fans of discreet, minimalist design will more readily appreciate their subtly shiny matte finish and quality construction.

What arguably matters more about any headphones’ physicality is comfort levels, and the Sennheisers nail this criterion. Their grip is secure yet not too tight, the positive seal of their pleather earpads isolates well, and the aptly cushioned headband ensures that the relatively heavy (311g) headphones aren’t burdensome on the top of your head.

You won’t ever forget you’re wearing them, as you might with light, slimline over-ears like the Bose QC Ultra Headphones (2nd Gen), but they don’t feel oppressive either, even during longer wear.

While headphone manufacturers seem to be torn as to whether to deliver key functionality with buttons or gestures, Sennheiser has stuck with a touch-control affair here, the only button on the right earcup launching your phone’s voice assistant.

We wish it turned Transparency mode on/off instead, which is activated by tapping the right earcup twice, but at least the touch controls are responsive and work across a generous surface area.

We like that every touch action is signalled by a sound, and they can be turned off in the app to prevent accidental touch when, say, you’re lying down or wearing a scarf.

That single button and touch-capacitive area aside, the right earcup simply houses a 3.5mm jack and USB-C charging socket, both of which can be used for wired listening with the supplied 1.2m cables, though do note that the headphones require battery life for either method.

You have limited excuse to be caught short, however, with the HDB 630 offering a liberal 60 hours of audio playback with ANC on, reducing to 45 hours when the dongle is in the equation.

The app offers a generous suite of functionality beyond assuring you of the audio quality you’re getting, including activating on-head detection, smart pause and auto-answer call features for hands-off playback control; one of the most comprehensive parametric EQs we’ve seen for such a product; and noise cancellation adjustment.

Noise cancellation

Truth be told, there isn’t a ‘but’ to be found; the HDB 630 are a well-rounded package. That said, they aren’t class leading everywhere. Their active noise cancellation qualifies for ‘good’ rather than ‘great’ in a market where Bose and Sony are dogged in their pursuit of silence, though it should be said that the HDB 630’s physicality goes further than most designs to isolate you from the outside world in the first place.

Their ANC system certainly takes the sting out of disruptive surrounding noise, reducing the rumble of traffic and bus engine noise – those kinds of low-end frequencies are typically the most distracting in your everyday life. Set ANC level to maximum and play music at a decent volume, and you’ll likely find yourself satisfyingly isolated.

But during a comparison, the Sony XM6 block noise slightly more effectively. You can more clearly detect revving engines through the Sennheisers, and we find that traffic whizzing by us catches our attention more. The Sonys (and more so, the Bose QC Ultra 2) provide a more intense feeling of ‘dead air’ between the earcups, and it’s easier to switch off from the noise world while wearing them, particularly when listening to low/mid-volume piano pieces.

Price

More features, improved sound and the unique inclusion of an audio-enhancing Bluetooth dongle understandably translate to a pricier pair of headphones than the Momentum Wireless 4, which arrived in 2022 for £300 / $349.95 / AU$549.95.

Sennheiser has been much more ambitious in both designing and pricing its latest flagship wireless over-ears this time round, reflected in the HDB 630’s name and positioning within the lineup – they’re the first wireless pair to be included under the ‘Audiophile’ 600 Series umbrella – and their £400 / $500 / AU$1000 launch price.

That doesn’t put them beyond their closest rivals, mind you. In fact, they’re squarely in the firing line of the Sony WH-1000XM6 (£400 / $450 / AU$699), Bowers & Wilkins Px7 S3 (£399 / $449 / AU$699) and Bose QuietComfort Ultra Headphones (2nd Gen) (£450 / $429 / AU$649), all of which are only notably more attractively priced than the Sennheisers in Australia.

Verdict

Sennheiser has reestablished itself within the noise-cancelling headphones market with the HDB 630, moving on from its competitive Momentum model to create something bolder, more ambitious and altogether better.

They move the goalposts for wireless sound quality at this level, while going the extra mile to upgrade iPhones and other audio sources to make it easier for people to benefit from it. And they also score well enough in the design, features and noise-cancelling departments to be considered a highly attractive all-round package.

For sound-conscious folk looking for convenience and audio quality, the Sennheiser HDB 630 are serious best-of-both-world propositions.

Review published: 3rd December 2025

SCORES

• Sound 5
• Build 4
• Features 5

MORE:

Read our review of the Sony WH-1000XM6

Also consider the Bowers & Wilkins Px7 S3

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