Marshall Monitor III ANC review: A rocking pair of flagship over-ear headphones

It won’t have escaped your notice that the price of flagship headphones has risen considerably over the past few years. The Apple AirPods Max, launched at £549 in 2020, have given the green light to brands to push the price of headphones designed for a mainstream audience to levels previously reserved for audiophile equipment. 

However, UK manufacturer Marshall has resisted the urge to go ultra-premium with its latest flagship, the Marshall Monitor III ANC. Its new over-ear headphones cost £300, which is certainly not chump change, but still rather reasonable considering what they bring to the table. 

Although not the perfect premium package, they come with an impressive suite of features that includes ANC and spatial audio, epic battery life, and some of the most intuitive controls I’ve encountered on noise-cancelling headphones. Oh, and they’re nigh-on indestructible. 

Marshall Monitor III ANC review: What do you get for the money?

The Marshal Monitor II ANC are rugged and lightweight over-ear headphones offering a comprehensive selection of features and various customisation options via the Marshall Bluetooth app.

I’ll talk more about the design decisions that set the Monitor III ANC apart from their rivals below, but they’re archetypally Marshall, with a leather-like texture used liberally and the brand’s iconic logo prominent on both earcups. Both cups house an individual PCB and battery and this contributes to a staggering battery life of 70 hours with ANC on, a figure that rises to around 100 hours with it off.

On the features front, you’ve got adjustable active noise cancellation and transparency modes alongside a proprietary “Soundstage” spatial sound mode and wear detection. There’s also Spotify Tap and voice assistant functionality and “Adaptive Loudness”, which optimises the tonal balance of your audio according to the level of ambient noise and volume at which you’re listening.

Five preset EQs are accessible via the companion app and you can create your own EQ using a five-band equaliser ranging from 160Hz to 6.25kHz. The headphones themselves have a wider frequency range than that, with Marshall stating coverage from 20Hz to 20kHz.

Audio is delivered via 32mm dynamic drivers – a little smaller than the 40mm seen most commonly in this class of headphones – and wireless connectivity is taken care of by Bluetooth 5.3, with codec support currently limited to SBC and AAC. I was told by one of the leads on Marshall’s audio team that a third codec will join that list later in the year but he wouldn’t confirm whether it was LDAC or aptX Adaptive. 

There’s also support for dual-device pairing but not automatic source switching; you’ll need to pause audio on one device before starting it on another. The Monitor III ANC are LE Audio-ready though, meaning they’ll support Auracast audio sharing when it finally becomes available.

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Marshall Monitor III ANC review: What did we like about them?

Back in 2020, we described the Monitor II ANC as having weaker noise cancellation than the competition. I’m pleased to say Marshall has made big strides in this department, with the Monitor III able to attenuate external sound far more effectively. 

There are three levels – Low, Medium and High – and the highest setting handled my daily commute admirably. The breadth of their attenuation is decent; mid-range and high frequencies still penetrate your ears occasionally but external distractions are generally kept to a minimum. The headphones’ Transparency mode works very well too, offering an impressive level of environmental awareness at the touch of a button.

On the subject of buttons, I love how the Monitor III ANC handle controls. The multi-directional control knob found on several Marshall Bluetooth speakers looks after audio playback, with two buttons inset into the yokes that connect the headband to the earcups providing access to features.

The button on the left yoke lets you cycle through the ANC modes, while the “M” button on the right yoke can have a single specific action assigned to it in the companion app. The choice of actions covers Spotify Tap, Equaliser, Voice Assistant and Soundstage – I chose the latter so I could engage spatial sound in an instant. This clever setup was extremely intuitive to use. I never found myself fumbling around trying to find a button and had access to all the commands I needed.

Controls aren’t the only innovative aspect of the Monitor III ANC’s design. Marshall has also done something unique with the headband. Rather than using foam to pad the underside of the band, Marshall has built in an elasticated rubber bridge tied to the earcups at each end to even out the pressure across your head. It works very well, particularly if you’ve got a bald head as I do. The headband is the most malleable I’ve come across too; you can contort the Monitor III ANC in ways I wouldn’t have thought possible and this allows you to fold them into a compact bundle for storage in a pocket or inside their hard-shell carrying case.

The case itself is a massive improvement on the Monitor II ANC, which only came with a canvas carrying bag. Not only does it provide superior protection, but it’s the smallest I’ve encountered on any premium headphones and looks great. The inside is lined with a red fabric that’s a welcome call back to some of the brand’s legendary guitar amps and an eye-catching flourish that contrasts the predominantly black headphones. 

If you’re a fan of the Marshall aesthetic you’ll appreciate the Monitor III ANC’s design, too. It encapsulates the brand’s rock and roll roots and complements the staple uniform of band t-shirt and a full sleeve of tattoos perfectly. That’s not my vibe, but I rather like the appearance of the Monitor III ANC. It’s a much more durable design than most too, with the cups said to be scratchproof. I stopped short of taking a knife to them but clawed and pawed them without any negative consequences. 

Like the design, the Monitor III ANC’s audio is tailored for a specific audience. I found their tuning agreeable for the most part, but they’re at their best when dealing with genres that have been the brand’s bread and butter over the past sixty years. The guitars and drums on Slash’s Apocalyptic Love had a well-judged timbre and energy to them and the vocals were articulated with a pleasing level of clarity. I thoroughly enjoyed the Monitor III ANC’s rhythmic expression across most genres and appreciated the speed with which they attack.

I was also impressed by Marshall’s new Soundstage spatial sound. This was created in-house and works with all types of content across any platform. There’s no head tracking, but, unlike most spatial sound modes, you can tweak it in a couple of ways. 

Sliders in the companion app allow you to increase or decrease the intensity and the size of the room you want to feel like you’re in and I was convinced by the virtualisation to the point I had it engaged more often than not. It’s a less vertical virtualisation than other spatial modes I’ve tested but the additional breadth added to Jimi Hendrix’s All Along the Watchtower enhanced the experience considerably without compromising quality to any tangible degree.

Finally, it would be remiss not to mention the Monitor III ANC’s bountiful battery life. The dual-battery system is said to deliver up to 70 hours of playback with ANC on and after a week of solid use, they’ve only just hit the 40% mark. They also support some nifty battery preservation tools, such as the ability to limit the maximum charge to 90% and to extend the batteries’ lifespan.

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Marshall Monitor III ANC review: What could they do better?

Codec support is the first thing that comes to mind. For this kind of money, I’d expect support for a lossless format such as aptX Adaptive or a high-resolution option for Android users like LDAC. As mentioned previously, there will hopefully be movement on this in the coming months but, at present, it’s a big omission.

I’m also not totally convinced about the Monitor III ANC’s long-term comfort. Their unusual headband works brilliantly and the padding on the earcups, which contains a combination of soft and performance foam, is supremely supple. It moulds against your head very well to create an effective passive noise-cancelling seal, but my ears started to feel a bit cramped and warm after an hour or so of use. I could have done with another centimetre or so of breathing room, though your mileage will vary.

For £300, I think the Monitor III ANC should feel and look a little more premium. That said, I understand Marshall’s commitment to the design language that’s served it so well for decades; it would be unwise of the company to disrupt this when it already has such a committed audience. 

Similarly, I’d like to have seen the Monitor III ANC’s low-end reproduction shown a bit more love. I listen to a lot of electronic music and found the headphones less satisfying when handling bass-focused genres. This isn’t just about how prominent bass is within the mix, but also how well-defined the lower frequencies are.

On Jarki Monno’s excellent Boys Still Cry, the guitar and vocals sounded spot-on but when the bass kicked in during the chorus I wanted a bit more punch and low-end definition. This was even more evident as the bass dropped on Kove’s drum and bass roller Searching. Engaging the Bass Boost EQ and creating an EQ with the lower registers enhanced helped with impact a bit, but did little to allay my feeling that I wasn’t getting the full low-end picture.

Marshall Monitor III ANC review: Should you buy them? 

I’ve openly admitted that I’m not Marshall’s target market aesthetically or musically, but I still rate the Monitor III ANC pretty highly. Their noise cancellation is to the level it should be given the asking price, sound quality is great for certain genres and the control options you have at your fingertips are among the best around. The content and platform-agnostic spatial sound mode is a welcome and immersion-enhancing addition, battery life is off the charts and the headphones themselves are incredibly durable. 

With a bit more breathing room in the earcups, support for a couple more codecs and slightly more attention paid to the low-end rather than mid-range they’d be a smash hit. As it is, they’re still worth considering as a cheaper alternative to options from the likes of Apple, Bose, Sonos and Beats and a no-brainer for Monitor II ANC owners looking to upgrade.