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Monitor Audio Platinum 300 3G

To celebrate its 50th birthday, UK speaker stalwart, Monitor Audio first turned out a remarkable concept speaker (originally called - hey! - ‘Concept 50’ but latterly known as  ‘Hyphn’) and then, by way of an encore, thoroughly overhauled its flagship Platinum range. These Platinum 300 3G are the flagship model of that flagship range, and as befits their position in the pecking order they are a) imposing and b) expensive.

Of course, these are not the first big, pricey speakers ever launched by a storied British loudspeaker specialist. But they represent the state of the Monitor Audio art, both where acoustic engineering and furniture-making is concerned - and what a big, lavishly specified and extensively varnished state of the art it turns out to be.

Some of Monitor Audio’s favourite technologies are deployed here. Three of the four drivers (the 102mm midrange and the pair of 203mm bass drivers) utilise the Rigid Diaphragm Technology that the company’s been refining for a while now - a Nomex honeycombed core sits between a very thin, very rigid ceramic-coated aluminium layer and a twin layer of carbon fibre that’s been layered and bonded at 90-degree angles for optimum strength. Big, powerful Neodymium magnets, a rearranged motor system and an underhung edge-wound voice-coil give great power-handling but better pistonic control at the same time - or, at least, that’s the theory. The tweeter unit, meanwhile, is carried over almost entirely unchanged from the Concept 50/Hyphn design study - it’s the third generation of Monitor Audio’s ‘Micro Pleated Diaphragm’ high-frequency transducer (or, as it’s more commonly known, a ‘ribbon tweeter’). The company’s acoustic engineers claim it features the lowest distortion and most even frequency response they’ve delivered so far, thanks in part to a newly finessed waveguide that delivers highly controlled directivity, consistent in both the horizontal and vertical planes, and consequently more convincing soundstaging. 

In every other respect, too, from the position and proportions of the rear-firing bass reflex port to the cross-over network and beyond, Monitor Audio has compromised as little as possible. If the company has a ‘statement’ product that’s on general sale, the Platinum 300 3G is it.

Sound quality

Of course, the Monitor Audio Platinum 300 3G are extremely talented loudspeakers, and in many ways - that’s hardly a spoiler, now is it? But what’s perhaps most gratifying about the way they go about delivering sound is the sort of effortlessness they embody, the utterly unarguable authority they demonstrate, the sort of instinctive correctness that’s more readily associated with statements like ‘2+2=4’.

From the bottom of the (deep, lavishly textured and detailed) frequency range to the (crisply attacking, equally detailed) top, the 300 3G are tonally convincing and entirely naturalistic. Despite the numerousness of driver (and, consequently, of cross-over) they sweep from bottom to top in an even, smooth and entirely plausible manner - and this equitable nature contributes plenty to the overall sensation of control and confidence. And in the midrange, where human hearing is at its most analytical, the Monitor Audio communicate almost torrentially - their eloquence and articulacy where vocalists are concerned is difficult to overstate.

Dynamic headroom is considerable (of course it is, you can tell by just looking at them), but these speakers are no less adept with the low-temperature harmonic variations that result from repeated presses of the same piano key. As far as detail retrieval and retention is concerned, the 300 3G are getting on for fanatical. But it’s the positivity of the way these speakers present music, as well as the amount of information they impart, that makes each listen an event.

Rhythmic expression is good, and even tricky tempos and twitchy time-signatures can’t throw them out of their stride. The balance they strike between intensity and analysis is deeply impressive - and the fact that they sound just as full, just as potent and just as persuasive at low volumes as they do at ‘party on!’ levels just adds to their appeal.

Yes, you can nudge them towards the boundaries of their comfort zone if you really want to - but only by setting you mind to it. Play some music that’s compressed, that’s mixed to sound good on the radio whereby everything is as loud as everything else and the soundstage is two-dimensional) and the level of control the Monitor Audio want to assert becomes inappropriate. But then, if you listen to stuff designed to sound good on the radio, go ahead and listen to it on a radio.   

Living with

At 1131 x 430 x 524mm (HxWxD) each, these are considerable cabinets and will dominate smaller listening rooms both sonically and visually. Monitor Audio has gone to great lengths to ensure they’re as decorative as furniture like this possibly can be - but 16 layers of flawlessly applied lacquer, etched inlays, some graceful curves to the cabinet itself, and a choice of piano ebony, piano black or matte white finishes can only mitigate the bulk so much. A per-speaker weight of 53.6kg tells its own story.

Once out the box and sitting on their spiked outriggers (don’t imagine this is anything less than a two-person job), the Platinum 300 3G prefer to be out in some open space, at least a metre away from a rear wall and toed in just a little towards your seated listening position. A redesigned spike arrangement means they can be adjusted from above using an Allen key, rather than the speaker having to be tilted while someone attempts to manipulate the spike without being pinned to the floor - which is nice.

Nominal impedance is 4ohms, and sensitivity is a bog-standard 88dB - but naturally you haven’t just spent five figures on some loudspeakers in order to drive them with anything less than heroic.     


Monitor Audio Platinum 300 3G ownership is not, as should be obvious, to be entered into lightly. They demand decent money to be spent on the rest of the system they’re involved in, and they demand plenty of space in which to operate. Accommodate them properly, though, and it’s difficult to know how you’re meant to identify a shortcoming in the way these speakers perform. 

Listening notes

Lost Girls Love, Lovers
One of the more concise 15min+ tracks you’ll ever hear, and given the works by these Monitor Audio speakers. It’s by turns intimate, wide-open, punchy, tender and quite startlingly fierce, and the 300 3G track it all faithfully and with no little enthusiasm.

Amon Tobin Get Your Snack On
A recording as snappy, good-natured and as dancefloor-adjacent as this may not seem ideal for a pair of big, expensive floorstanders to show what they’re made of. But it turns out the Platinum 300 3G can turn their hand to more-or-less anything. 

Scott Walker Farmer in the City
A tune that sounds as portentous as the 300 3G look - unlike the speakers, though, the song has no relief in it whatsoever. But its theatricality, its Bible-black humour and its extraordinary dynamism prove to be right up the Monitor Audios’ street. 

What the press say

Why you should buy it

Because you have the space to spare, the system to cope and a desire to hear every scrap of information in your favourite recordings delivered in a balanced, judicious and hair-raisingly immediate manner.

Video review

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