KEF X300A review - Solid sound that adds real weight to music yet remains acoustically neutral

Active powered loudspeakers that are built for sound

There are desktop speakers. And then there are loudspeakers that will also fit on the desk. The difference? It all comes down to the sound quality.

In the case of the KEF X300A, we have a pair of active powered loudspeakers that were built for the best sound at a reasonable budget. That’s not a KEF marketing quote, but our judgement based on extended listening.

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They also happen to fit on the desk, helped by smart and tidy build, and by a custom adjustment switch on the back that optimises the acoustic characteristics for that kind of positioning away from free space. 

On first sight, the KEF X300A looks like a regular bookshelf hi-fi speaker, albeit one with an unusual concentric driver arrangement. Instead of the classic tweeter above mid-bass driver layout, the tweeter is embedded at the centre of the main driver. This KEF UniQ unit should help create a more even tonal balance from different listening positions, and assist stereo imaging – and this is demonstrably the case, as we found an unusually consistent sound from different locations.

XEF 300A: Build and design 

The KEF X300A may resemble the long-standing brand’s typical fare of high-fidelity loudspeakers from the last few decades, but this particular speaker is self-powered, with four separate channels of amplification. It also features active crossovers, working in the analogue domain, for splitting the sound into treble and mid/bass frequency bands before it hits the amplifiers.  

This is a crucial step, one used in professional PA and studio monitors, which really optimises the signal that reaches each speaker driver, as well as being a more efficient way to power any speaker. 

In this system, the amps live inside the speakers, along with the associated electronics – and that includes D-A convertors (DACs) so that you can feed the X300A speakers with a digital signal, up to the 24-bit/96kHz standard, through a single USB input.

It’s also notable that the amplifiers used are high-fidelity Class AB designs (50W for mid/bass, 20W for treble), and not the music-crushing Class D type that is found in cheap mass-market audio products. 

Build quality is essentially faultless. These speakers feel incredibly solid and they’re very weighty too at 7.5kg each. The front baffle is devoid of any grille or cover and is finished in matt black, with matching black trim rings. The main carcass of the speaker box resembles course-grained metal, although it’s likely a vinyl wrap over thick-walled MDF. Even so, it feels very tough.

On the back of the left speaker – the control unit of the pair – there is a Mini-USB 2.0 port for the digital audio input from a computer, as well as a 3.5mm mini-jack analogue input. A second USB port sends the signal to the right-hand speaker over an included USB cable. To tailor the sound for Desk or Stand use there’s the small slide switch here, while a rotary trim knob lets you adjust overall volume gain.

XEF 300A: Performance 

These are incredibly revealing loudspeakers, and yet tonally very neutral – sometimes ‘revealing’ can be a euphemism for overly enthusiastic treble, for example, which gives a false impression of ‘detail’. We ran them from a MacBook Pro and various iMacs over USB, playing a variety of 16-bit CD-ripped lossless files, as well high-resolution 24/96 material.  

Regular CD music had a clarity and sparkle that we’ve not heard at this price level before – the overall grip and cohesiveness of sound outclassed what you might have expected from, say, a traditional stereo hi-fi amp and loudspeaker combination of £300 each. 

Voices were fixed naturally in the space beween the speakers, and free of unwanted chestiness from the cabinet or sibilance from the all-metal drivers. Acoustic music played convincingly, capturing the air and space around instruments while showing authentic timbre of guitars or violins, for example. And the Uni-Q helped lock the sound such that the soundfield remained consistent in size and spread. 

Steady stereo soundstaging was a creditable strength, which let us enjoy music from a wide range of listening positions. 

Given weightier music material, the X300A could also step up and keep up. In fact their tight, focused bass made them great for rock and jazz material, remaining in control even at higher volumes where other speakers start sounding messy. The rear-ported acoustic design allowed them to go relatively low in the bass, and without troubling low-frequency port or box resonances.

OUR VERDICT

As a self-contained speaker system, the KEF X300A stands clearly above the style-first speakers that are usually sold to accompany a PC or laptop. These KEFs have a solid sound that adds real weight to music yet keep acoustically neutral with barely any coloration from the box or electronics. A majestic achievement.

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