KEF Muo (2nd Gen) Review

Design

Its dimensions, relatively light weight and very promising IP rating would tend to indicate the KEF Muo is a go-anywhere, do-anything kind of Bluetooth speaker. And it’s true, it’s built to survive in any realistic environment and to be no kind of hindrance when it comes to getting there or coming back again.

But bear in mind the majority of the Muo is built from smooth, tactile and exquisitely finished aluminium. The sort of material, in fact, that it’s not especially difficult to mark or scratch or even dent. So if you do intend to take your speaker with you into the Great Outdoors, be aware that there are devices that lend themselves much more readily to being slung into a backpack and bounced around in there than this one.

And you’ll want to keep it pristine, because in any of the available finishes the Muo (to my eyes, at least) looks the business. I wouldn’t necessarily choose the Midnight Black of my review sample, but I’d happily take any of the Silver Dusk, Moss Green, Blue Aura, Cocoa Brown or Orange Moon alternatives.

There are some physical controls integrated into the rubber end-cap at the top of the speaker – they cover power on/off and volume up/down, and there’s a multifunction button that takes care of skip forwards/backwards, play/pause and answer/end/reject call (the mic that turns this into a speakerphone features noise- and echo-cancellation technology). There’s also a button to initiate Bluetooth pairing at the rear of the speaker – it’s just next to the USB-C slot.

Features

• Bluetooth 5.4 with aptX Adaptive
• 40 watts of Class D power
• Auracast-enabled

There are a couple of ways of getting audio information on board the Muo. The USB-C slot at the rear of the cabinet can be used for data transfer as well as charging the battery, and wireless connectivity is dealt with by Bluetooth 5.4 that’s compatible with the SBC, AAC and aptX Adaptive codecs. These options can deal with 16-bit/48Hz and 24-bit/48Hz resolutions respectively.

And there are further connectivity options. The Muo is Auracast-enabled, so can be part of an extremely expansive system as long as it’s partnered correctly. Two Muo (Muos?) can form a stereo pair. And both Microsoft Swift Pair and Google Fast Pair are available, too.

Once the digital audio information is on board, it’s delivered by a two-driver array powered by a total of 40 Class D watts. A 20mm tweeter takes up 10 of those watts, the other 30 is taken by a 117mm x 58mm racetrack mid/bass driver that features the company’s P-Flex technology – this arrangement, says KEF, results in a frequency response of 43Hz – 20kHz.

There’s an accelerometer built into the Muo which allows it to detect its orientation and adjust its sound output accordingly. In portrait position, the tweeter is above the mid/bass driver; put the speaker into landscape orientation (it is fitted with four small rubber feet for this purpose) and obviously the drivers are now side-by-side.

You can also exert control over the Muo by using the KEF Connect app. In this guise it deals only with input selection and volume control, but it does at least give access to five EQ presets and an indication of battery life too.

Battery life is quoted at 24 hours from a single charge (at moderate volume levels, naturally), and should the worst happen you can go from flat to full in around two hours via the USB-C input. A quick 15-minute burst should be enough to get another three hours of playback (again, provided you’re not going for it where volume levels are concerned).

Sound Quality

• Nicely shaped and varied low-frequency response
• Sizeable and detailed presentation
• Can sound slightly strident, especially through the midrange

For a relatively compact speaker in physical terms, the sound the Muo makes is anything but discreet. No matter if you give it a bog-standard 320kbps MP3 file of Private Life by Grace Jones to deal with or a bigger 24-bit/44.1kHz FLAC file of By Storm’s Dead Weight, the KEF sounds big and spacious, and delivers a presentation that easily escapes the confines of its cabinet.

It extracts and reveals plenty of detail, both broad and fine, at every stage of the frequency range – which goes a long way to convincing you, as the listener, that you’re getting a full account of what’s going on.

Down at the bottom end there’s a lot of information regarding texture made available, and bass sounds are nicely shaped and controlled too – so as well as an impressive amount of variation at the low end, rhythms are expressed with genuine positivity. It’s a similar story at the opposite end, inasmuch as treble sounds have shape and substance to go along with a fair amount of bite – and harmonic variation is apparent at every turn.

As well as the more understated dynamics of harmonic fluctuations, the Muo is also quite adept at dealing with the big dynamic variations that come when a recording ramps up the volume or the intensity. It has no problem tracking changes in attack, and maintains the distance between quiet and loud even if you’re listening quite loud in the first place.

Turning the volume up doesn’t alter the evenness of the frequency response or harm the natural, neutral tonality the speaker demonstrates at either end of the frequency range, either.

In the midrange, though, things aren’t quite so clear-cut. There’s still an admirable amount of detail available, and the transition from the midrange to the stuff going on either side of it, is smoothly and naturalistically achieved.

But there’s not a huge amount in common where tonality is concerned – the way the KEF hands over the midrange in general, and voices in particular, isn’t in absolute sympathy with the bass or treble reproduction. There’s a mild abrasiveness to the tonality here, which can result in voices becoming slightly strident or, in extremis, actually rather hard-edged and unyielding.  

Should you buy it?