What do you look for in a Bluetooth speaker? Is it sophistication in design? Is it smart voice control? Or it brutal bass and a lighting rig that puts that tricked-out Ford Escort XR3i to shame?

If it's the last, then the Sony XB40 won't have escaped your attention. The XB stands for "extra bass" - a line that Sony has been successfully following through in its headphones and speakers for a number of years.

We've been getting heavy with the Sony SRS-XB40. Here's how the party speaker fares in among today's Bluetooth portables.

  • 279 x 100 x 105mm; 1.5kg
  • Rubberised finish in red, black, blue
  • IPX5 water protection
  • Strobe and line lights

The XB40 is one of the larger Bluetooth speaker models, so although it's portable, it's probably more likely to be something you throw in the car rather than your backpack. 

With rugged looks and water protection, the XB40 comes with an IPX5 rating, meaning it will survive getting caught in the rain, splashes from the pool or sitting in a puddle of spilt beer.

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There's a rubberised finish to the body too, which gives it that tough look: it's less of a sophisticated statement about industrial design and more a lairy plaything.

There are plenty of speakers that take this approach - the UE Megaboom for example - although this Sony speaker dwarfs that example with its sheer size, even if Ultimate Ears goes a step further in offering more comprehensive water protection. 

The front of the XB40 gives way to a grille that's encircled by a ring of illumination, adding a light show to the speaker, which is paired with strobes that illuminate the cones behind the grille - if that's how you want it to play. 

The top offers chunky controls with a solid power button and an "extra bass" button. If you want the XB40 to offer less bass then this button also has you covered - although it's a little like pulling the V8 out of a Ford Mustang, but if your neighbours are complaining about the shaking walls, then this is one way to deal with it.

Other controls offer phone answer/hang-up, play/pause, the essential volume control, and an "add" button that gives you the chance the pair this speaker with another XB model for a brutal bass stereo pairing.

Pocket-lintSony SRS-XB40 image 3

There's nothing subtle about the design of the XB40; but this isn't a speaker that's designed to be subtle. It's the sort of speaker you might choose to rock your house party, provide the soundtrack for your dance studio or just use to brighten up your room. It's also perfectly suited to sit on a mantelpiece or shelf, powering music into the room.

  • Strobe lighting
  • Coloured lighting ring
  • Light control through app 

Core to the XB40's offering is the light show. It's not unique to this model - the XB20 and XB30 offer lighting too - but it's a pretty unusual offering on a Bluetooth speaker. Sony has long been producing some crazy bass systems with lights incorporated and this foray into smaller devices makes for something a little different. You can't call it boring, you might call it bizarre.

It's also the only thing that people talk about. While the likes of Libratone will diversify with cloth finishes, or other manufacturers with voice control, it's the XB40's light show that gets people excited. It's an immediate novelty that big and little kids will love, because it's an instantaneous portable disco.

Sitting across the room with those lights constantly flashing can be a little overbearing, however, so we thank the maker that a long press on that Extra Bass button will shut the lights off.

You can also switch from the default light mode - called "rave" - to a more ambient colour illumination with no strobe. To do this you'll need to use Sony's Music Centre app. Once your phone is connected to your speaker - which is a breeze with NFC pairing - you'll be able to change the speaker's settings, including the illumination.

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If you want it more ravecore, there's a straight strobe option for the lights too. Unique? Yes. A bit of fun? Certainly. But it's also one of the biggest talking points about this speaker. The other talking point, of course, is the bass. 

  • Brutal bass delivery
  • Offensive volume potential
  • 24 hours of banging out tunes 

With Extra Bass in the name, you're naïve to think this Sony will deliver anything less than almost overpowering bass. It sets the XB40 up as a speaker that's specifically for those people who want the bass to reach out and kick them in the gut, which is what you get. You can't criticise it for doing what it says on the box.

There's a wonderful richness that comes with this bass when turning it up loud and letting the passive radiators do their stuff. While the main left and right drivers fire to the front, the bass seems to pour out of the front and back. The good thing is that it doesn't distort and there's no vibration from the casing, so it can deliver that bass without distraction.

Pocket-lintSony SRS-XB40 image 5

As it's not a reference "balanced" delivery, that means that the XB40 leans towards dance and urban music a little better than it might classical or something where the vocals are more subtle. It doesn't really let voice shine with the bass muddying things - and even if you're just listening to the radio, while Katy Perry's Swish Swish sounds wonderful with added drive to the bass, the adverts that follow sound like a mess.

Switch off the bass and you're left with a speaker that feels like something is missing, but we like that it's so easy to do this. It adds versatility, so if you happen to be listening to a programme on BBC Radio 4, you can settle things down the normal.

Stream your favourite albums from Spotify and the chances are, if you're a bass lover, you'll be perfectly happy with the results and the volumes that you can achieve. This is a loud speaker.

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The battery life is also impressive, with 24-hours of playback. There's also a USB connection on the rear so you can charge your phone from the speaker, because the chances are that your phone won't last that long. But it does use the sort of power pack you'd expect to find with a set-top box for your TV, so there's no chance of charging this with the USB charger you might have for your phone.

  • LDAC support
  • Sound customisation through the app
  • Lacks any sort of smart functionality

Aiming to boost the performance of Bluetooth is support for LDAC. This is Sony's answer to boosting wireless music, transmitting three times the data that regular Bluetooth does. The aim is to get your Hi-Res music sounding great, because it sends over more of the data that regular Bluetooth might lose. 

That's good in principle, but we found the LDAC transmission wasn't as reliable as regular Bluetooth. When using the app, you'll be able to see the LDAC indictor appears, with settings in the app that will let you enable or disable when compatible hardware is detected. LDAC does give a noticeable lift, with clearer overall delivery in the mids and highs, providing a little more escape from the bass for more dynamic performance.

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However, as tested with the Google Pixel XL, we found some breaks in LDAC transmission, leading us to disable it for a smoother Bluetooth experience. We suspect that some devices might fare better, like the Sony Xperia phones built with LDAC in mind - although we didn't have a device to test this, which might be the case for many other potential users.

What's missing for a 2017 speaker is any sort of smart functionality. With a lot of makers turning to the likes of Google Assistant or Amazon Alexa, the XB40 is cut from a different cloth. This is about balls-out bass thrills, rather than smart AI fun.

Verdict

Exuberance is the XB40's raison d'être, which is exactly what you get - unapologetic extroversion. Brash bass and big beats, serious volume, plus the lights fantastic. And all that wrapped up in a rugged-looking and colourful design.

For that we can't fault the XB40, because it delivers that funky light show and brings a lot of fun with it. Strip away the bass and you don't have the cleanest sound you'll find on the Bluetooth speaker, nor the greatest degree of sophistication, but that wasn't the aim here. The 'Extra Bass' button being a big clue.

Someone has to bring the fun to the party and, in this case, it's the Sony XB40.

Pocket-lintAlternatives image 1

We've been impressed with Ultimate Ear's Boom speakers. Offering 360 degree sound, there's plenty of volume delivered from this Bluetooth speaker and recent updates have added Alexa skills to the mix too. UE will also let you pair up multiple speakers in party mode boosting already good sound quality. On top of that, the chunky design really does offer protection, so this really is a take-anywhere speaker.

Read the full review: UE Boom 2

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Libratone's groove comes from the zip that gives this speaker a distinct look. While the design serves up some fun, it's a serious sound that comes from this speaker. There's 360-degree sound and excellent performance from this speaker, along with a range of useful features, like the ability to tap to mute it. Alexa has recently been added to the list; it's also Spotify Connect compatible and has recently added AirPlay 2 too.

Read the full review: Libratone Zipp