Bowers & Wilkins Diamond Surround Sound System (BMW iX) review

A sensational sound system befitting BMW’s flagship electric SUV Tested at £5000

In-car surround sound: Bowers & Wilkins Diamond Surround Sound (BMW iX)
(Image: © BMW)

What Hi-Fi? Verdict

If you want to be fully immersed in music while driving, this Bowers & Wilkins system will happily oblige. It’s talented and hugely entertaining.


  • +

    Excellent integration

  • +

    Breathtaking soundstage

  • +

    Loads of detail

  • +

    Impressive infotainment set-up


  • -

    Rhythmic drive could be better

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Testing an in-car sound system is a lot like testing a hi-fi system. It doesn’t take days of listening out on the road (or parked in a McDonald’s car park) for a good set-up to stand out. Sometimes it only takes a couple of tracks for it to get your feet tapping and let you know you’re in the presence of something better-than-average.

Of course, you still need to spend time getting to know exactly what its full capabilities are and to hear if there any chinks in its armour, but a system that makes this kind of impact tends to be heading in the right direction. And that’s the feeling you get when you fire up the Bowers & Wilkins Diamond Surround Sound system for the BMW iX. In fact, as time goes on (and as you’ll find out by the end of this review) this set-up is rather special.


The way Bowers & Wilkins systems are handled by BMW means they tend to come as part of a bigger package that can be applied to most models in a particular range. This was the case for the B&W system when the iX originally launched. It was part of the Technology Plus Pack, a £5000 option, that also includes extra features including an Interior camera option and its Parking Assistant Plus tech. At the time of writing, however, due to global supply constraints, it's been withdrawn as an option and can only be had on the top-of-the-range iX M60 where it comes as standard.


In-car surround sound: Bowers & Wilkins Diamond Surround Sound (BMW iX)

(Image credit: BMW)

The Diamond Surround Sound System features no fewer than 30 speakers, driven by a 1615 watt 28-channel amplifier. The configuration includes a 25mm B&W Nautilus Diamond Dome tweeter in each of the front doors and a two-way centre speaker on top of the dashboard. 

Because the iX is an all-electric vehicle, B&W has more options for the location of drive units. In particular it’s been able to optimally position a carbon fibre subwoofer under each of the four main seats. B&W’s even found space to include 3D speakers in the headliner and eight headrest speakers.

In the iX, the only hint there’s a premium sound option fitted to the car are the laser-etched brushed stainless steel covers for the tweeters. They have a triangular hole pattern to echo the design language of iX and their own lighting effect when used in the dark. The midrange speakers in the doors are positioned behind a surprisingly thick ‘acoustically optimised’ fabric, which is in keeping with BMW’s ‘Shy Tech’ design concept.

But the list of speakers used in the iX doesn’t stop there. The B&W system also includes what it calls ‘4D Exciters’ with two built into the backrests of each of the front seats. They’re designed to intensify how bass notes are felt, and their intensity can be adjusted via the main menu system.


In-car surround sound: Bowers & Wilkins Diamond Surround Sound (BMW iX)

(Image credit: BMW)

The cabin in the iX is a great place to sit. Not only does the front feel cavernous thanks to a lack of transmission tunnel, you’re greeted by one seriously smart-looking infotainment system.

Behind the wheel sits a 12.3in Information Display which is also connected to an even larger 14.9in Control Display, creating one huge curved display aimed at the driver. The sheer expanse of screen estate means it’s not out of reach to passengers, though - they can also get involved in controlling all the various functions without any major fuss.

The touchscreen is hugely impressive and uses a tile system to display the different functions at your disposal. Swiping through it and tapping on the various menus works pretty intuitively. There’s plenty of real estate for your fingers to make all the right presses while the crisp, punchy graphics and icons really stand out in daylight and at night time.

In-car surround sound: Bowers & Wilkins Diamond Surround Sound (BMW iX)

(Image credit: BMW)

Steering wheel-mounted controls take the form of a small nub on the right side which you push left or right to to skip track and a D-pad on the left which you press up or down to change volume. Both methods do the job, but we wouldn’t say they were particularly pleasant to the touch. Other rivals offer more tactile controls and a greater feeling of refinement.

The centre console looks interesting on the iX. The focal point is the glass iDrive controller, the look and feel of which is a definite opinion-splitter, but there’s no questioning how easy it is to use to navigate through all the various on-screen menus. BMW have used this method for a long time and haven’t tried to fix something that isn’t broken.

The rest of the panel on which the controller is mounted (it’s made from FSC-certified (Forest Stewardship Council) wood which means it comes from a sustainably managed forest) features icons for selecting different functions from Media to Navigation. They’re slightly raised to make them easier to find but we think they’re somewhat a little vague in the way they respond. You do get a scroll wheel for volume here, though, which is a welcome addition.


In-car surround sound: Bowers & Wilkins Diamond Surround Sound (BMW iX)

(Image credit: BMW)

Bowers & Wilkins provides you with a handful of sound profiles to choose from to help find a balance you like. On Stage attempts to put you right in the middle of the music. It feels like you’re the lead singer with different elements branching off from you and it also seems to give low frequencies a slightly heftier kick.

‘Rear’ shifts the focus of the sound to the rear of the car, so it’ll probably be the least used out of the four, unless you want to send the Teletubbies greatest hits to younger family members in the back.

Concert Hall does exactly what it says on the tin. This mode seems to add more in the way of echo and reverb and gives you more of a feeling of being sat in a large hall. One to try, perhaps, if you’re into classical, but not our favourite.

Which brings us on to the Studio setting. It’s the most neutral and authentic of the lot and music sounds more natural, solid and convincing. We’d recommend doing the bulk of your listening in this mode.


In-car surround sound: Bowers & Wilkins Diamond Surround Sound (BMW iX)

(Image credit: BMW)

Before we press play on our favourite playlist, to give you a tease of what’s in store, the system sports a demo mode which plays a 5.1 FLAC track inside the car, complete with HD video to give a bit of visual impact. Think of it like the longer version of the Dolby Atmos or THX splash that you get in the cinema before the main event. It’s a clever showcase – sounds fly across and around your listening position, but it’s no substitute for music, so we fire up the system for a listen…

And the first thing that hits you is the soundfield. It’s expansive, far-reaching and filled with detail. We haven’t heard many systems deliver so many layers and serve them up in such a wide window. The iX is an electric SUV and the lack of an internal combustion engine definitely has benefits when it comes to cleaning up a lot of background noise and allowing the music to take centre stage.

You can’t help but be impressed by the level of integration from the system. With 30 speakers on the go, it can’t have been easy, but you’ll struggle to find any chinks in this system’s armour. Highs and mids work in unison but even more impressive is the way bass notes are handled. Some systems struggle to sew low frequencies into the rest of the sonic tapestry, but in the iX everything can be digested in one piece.

We start with Kanye West’s Black Skinhead and see how the system handles its rolling, probing bassline. There’s plenty of drive and power on tap – the system can be cranked high without ever buckling under the sonic load.

In-car surround sound: Bowers & Wilkins Diamond Surround Sound (BMW iX)

(Image credit: BMW)

The 4D speakers bring vibrations to the proceedings and shake in time to the bass frequencies, enhancing the leading edge of notes and rumbling along to the end. Try them out by all means, but for us, the novelty wore off quite quickly and we’d only use them on one of their very lowest settings. Any higher and we feel they actually distract from the sound instead of adding to the experience.

While we’re talking about the seats, we also prefer dialling down the personalised surround intensity of the system, i.e. the headrest speakers. Set this too high and in our opinion too much information is pumped out of them, which spoils the soundfield.

Play something a bit more revealing such as the acoustic version of Yonaka’s Rockstar and the Bowers system does a great job of communicating the intimacy of the track. That immense soundstage comes to the fore once again, the vocal positioned high up in front of you like a shining beacon. As each piano key is pressed, the system extracts loads of detail; each press is superbly defined and precise and the system does a superb job of revealing the tremors in the singer's voice. There’s a delicacy to the layering of detail that some systems just can’t reproduce.

Switch to End Credits from Pirates Of The Caribbean: On Stranger Tides and the B&W system powers the track along. Drums hit hard and provide a solid foundation for the rest of the orchestra to build on. The speed at which the strings are played adds to the drama, rising and falling with impressive speed and agility. A lot of car systems seem to struggle with timing and although not completely perfect, this set-up does a good job of locking onto and tracking rhythms.


We’ve tested a few BMW-based Bowers & Wilkins sound systems over the years and we have to say this is arguably the best of the lot. The imaging is excellent, detail levels are impressive across the board and the whole thing is glued together thanks to the top-notch integration of all those speakers. It’s a shame the system is only available on the flagship iX M60 at the moment, because if you were ordering one, then this is the one option we'd have at the top of our list.


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What Hi-Fi?, founded in 1976, is the world's leading independent guide to buying and owning hi-fi and home entertainment products. Our comprehensive tests help you buy the very best for your money, with our advice sections giving you step-by-step information on how to get even more from your music and movies. Everything is tested by our dedicated team of in-house reviewers in our custom-built test rooms in London, Reading and Bath. Our coveted five-star rating and Awards are recognised all over the world as the ultimate seal of approval, so you can buy with absolute confidence.

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  • Bloke
    WHF should consider separating its car audio content into a separate entity, or failing that, do a round-up every 6 months, say. If you don't have the car being reviewed, it's basically irrelevant. That and the table/phone/multimedia reviews and you're effectively T3.