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PSB M4U True Wireless Micro Planar Earphones

Canadian audio company PSB recently celebrated its 50th birthday, but despite its audio legacy the brand is a relative newbie to the headphone market - it dropped its first pair of cans only 12 years ago. It wasn’t until 2018 that PSB joined the true wireless bandwagon, and now - some six years later - it has unveiled its second iteration of true wireless headphones. 

The PSB M4U True Wireless Micro Planar Earphones are an unassuming pair of earbuds. Gone is the over-the-ear hook found on the original TW1 - it’s been replaced with an upside-down teardrop design and a sleek black aesthetic that’s in keeping with the majority of the true wireless market. 

It’s not a case of style over substance, though. Under the hood, the M4U’s are loaded with modern technology designed to provide a great listening experience. They are the first true wireless earbuds from the brand to feature a dual driver, which leverages Magneto-Static technology more usually found in loudspeakers. One transducer is dedicated to higher frequencies, while the other is solely for low frequencies - but they work together to offer good audio. 

Then there’s the Audiodo Personal Sound technology, which calibrates each earbud based on the results of a short hearing assessment taken in the app, to ensure the sound is perfectly suited to the wearer. 

Sound Quality

The PSB M4U True Wireless Micro Planar Earphones offer a pleasant listening experience. The sound is clean and detailed, with the top end and vocals sounding bright and clear. We Can’t be Friends by Ariana Grande sounds crisp, with the electronic tones balanced nicely alongside the soulful vocals. There’s also a subtle sense of bass audible both when the volume is turned down low and when cranked up high, and it doesn’t become muddy at louder levels either.  

The Personal Sound technology, which is built into the headphones, works well - in fact, it turns the good listening experience into a great one. The three-minute hearing test, which is available through the PSB Headphone control app, is simple to complete and calibrates each earbud independently. Before taking the hearing assessment and applying the subsequent sound profile, Beautiful Things by Benson Boon sounded a little dull and lacked sparkle - but with the sound profile switched on it is clear, with equal weighting given to the gently lilting vocals, and rhythmic guitar as the track reaches its crescendo.  

Podcasts and calls both sound good through the headphones, too. The earbuds reproduce the low frequencies of Chris Ramsey, and the higher tones of wife Rosie, equally as well when listening to the Shagged, Married, Annoyed podcast, making it feel as though the conversation is happening in front of me. Meanwhile, when making calls though the M4U both voices are clear and there is no distortion during the conversation. The microphone on the earbuds only picks up the occasional external sound, such as a car driving past, during the call - which helps make for a very pleasant experience. 

The audio isn’t perfect, however, and that’s down to one gripe when it comes to bass. There’s no denying lower frequencies are clear, but they sound a little too hollow for my personal taste when played through the M4U. Alibi by Ella Henderson and Rudimental has powerful bass, but the rich warmth that finishes the notes is lacking, and the overall effect isn’t quite as powerful as I know it can be.

Living with 

The PSB M4U True Wireless Micro Planar Earphones are a similar size to other true wireless earbuds on the market but, though they protrude further out of my ears than my Apple AirPods Pro, the upside-down teardrop design and the sleek black finish make them appear more discreet than others I’ve reviewed recently.  

Tapping the physical button on either earbud once pauses and plays audio, while additional taps on the right earbud control the volume, and the same taps on the left earbud skip forwards and backwards through tracks. 

When it comes to the smarts we’ve come to expect in modern headphones, the M4Us are a bit of a mixed bag. As I’ve already mentioned, they offer a hearing assessment - and when using the results the sound is automatically tweaked to suit you. Alternatively, an in-app equaliser means you can manually choose from presets that prioritise dialogue or tighter bass (among others). However, I am disappointed that the headphones lack simpler features, such as automatic pause (which is activated when one, or both, of the earbuds is removed) and the ability to customise the actions performed when tapping on the earbuds. This can make a world of difference to wearers. 

There’s also no active noise-cancelling built into these headphones, which is a little disappointing given that many competitors in the same price bracket include it. Consequently, I’m not fully immersed in the music as quite a lot of ambient sounds are audible when using the headphones while walking through a busy weekend thoroughfare. 

The earbuds last around eight hours before they need charging, which is usefully longer than the six hours the majority of competitors offer. The case, which is slightly more compact than other true wireless earbuds, offers an additional 24 hours and can be charged by the included USB-C cable or on by a Qi wireless charger, too.


The PSB M4U TWM Planar Earphones are a solid-sounding pair of wireless earbuds, although the bass is a little hollow for my taste. That said, the headphones boast good battery life and a useful hearing assessment, which can tweak the sound to suit your ears perfectly. However, they lack noise cancelling and a few other features other more affordable earbuds have as standard.  

Listening Notes

Michael Marcagi Scared to Start 

The PSB M4Us make this track an extremely pleasurable listen. The soulful vocals shine, while the well-rounded bass and the gentle strum of the guitar are perfectly balanced. 

Madonna Borderline 

With plenty of sparkle in the high-end, and the subtle percussion audible, this track from the Queen of Pop’s debut album sounds clear and just as fresh as it did in the early 80s. 

Sam Smith Money on my Mind 

The upbeat electronic sounds of this 2010s dance anthem sound sublime, with Smith’s melodic vocals really shining through over the pumping bassline. 

What the press say

Why you should buy it

Well-suited to anyone looking for a long-lasting, discreet pair of true wireless headphones that offer the ability to personalise the sound to suit your hearing. However, at £199 they’re a bit pricey and best suited to those who prioritise sound quality over  noise-cancelling technology, auto-pause and customisation of the controls.

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