Hi-fi enthusiasts often debate the very definition of hi-fi. In olden days when classical music and jazz were the mainstays of music, hi-fi systems were seen as the path to reproducing the live experience, to create a concert hall or a jazz club right there in your drawing room. But as music became created more in the studio, once The Beatles began creating music that was never intended to be performed live — well, what was hi-fi supposed to do with that?

The answer, to our minds at any rate, is that hi-fi should deliver as close to what the band and engineers heard in the studio. That’s what they made, that’s what they want you to hear.
How do bands hear their music when they’re recording it? They don’t have speakers in their vocal booths or hiked above the drum-kit. No, they wear headphones. Closed headphones, to avoid spill. Solid well-built headphones, to survive the knocks of studio life. And usually headphones with a pretty flat response, particularly during the mixing process, when any bumps and dips in response would create a final result which would have inverse dips and bumps when played on anything else.

So should you perhaps consider listening to music on a studio-style headphone?

Equipment
Audio-Technica is one company which has taken its strengths in the studio market and turned them to advantage in the consumer market. Indeed the ATH-M50x is a model which has made the jump all on its own. Introduced as a variant of the ATH-M50S after the company’s 50th anniversary in 2012, they were (and still are) listed as ‘Professional Monitor Headphones’ even when the company started releasing white, then red, then black and blue models which were surely aimed more at the street than the studio (click here for our review of those) . With those versions you still got the studio-style curly coiled cable, but also a long 3-metre minijack-terminated cable, and a shorter 1.2m minijack cable clearly intended for portable use, though a lack of inline smart controls maintained the studio illusion.

Now the consumer angle has been made entirely self-evident, by these latest ATH-M50xBT versions, which gain wireless Bluetooth operation. While there ain’t no Bluetooth in studios, out in consumer-land it’s now an essential — last year was the first ever when wireless headphones outsold cabled ones.

Quality is the question. Bluetooth remains a poor substitute for cable, even when, as here, there are higher level codecs included than the base-level SBC. The ATH-M50xBT can use the AAC codec, which lifts Apple phones to a higher level (though still not to CD quality), and also the Qualcomm’s aptX codec, which allows Android phones that support it to get even closer to CD standards with its mildly lossy compression.

There’s also the question of whether the headphone creators should adjust the voicing to compensate for the vagaries of Bluetooth sound and the internal amplification now required to deliver it — they do this at their peril, however, as there is then the risk of thereby mucking up the sound via cable. These are the things we listen for when testing wireless headphones.

The ATH-M50xBT certainly reassure in their presentation. They remain closed headphones, of course, and retain the large 45mm drivers backed by copper-clad aluminium voice coils, though the magnets are now labelled as ‘rare earth’ rather than neodymium. Gone are the longer curly and straight cables, with just the 1.2-metre minijack cable in the box, which gains inline controls. And you get the USB charging cable for the internal battery, which is quoted as delivering a healthy 40 hours of use after seven hours of charging.

The headband and ear-cushions are just as comfortable as their wired pedecessors, designed as they are for long listening sessions and durability. But new are all the controls required for Bluetooth operation — a power slider, and volume and play/pause buttons positioned around the right headshell (see below). The volume buttons double as last/next track controls if you hold them for a rather long two seconds, the play/pause button doubles as a call answering button.

There’s one last control — the central audio-technica logo on the outside of the headshell can be pressed and held for two seconds to activate your phone’s voice assistant, for which there is now a single microphone, also used for voice calls.

Performance
It all works, and is intuitive to use. We worry about power sliders as they’re easy to leave on by mistake, but the M50xBT fairly smartly shuts itself down in the absence of a connection… though not if you leave your phone nearby, as they’ll remain connected.

We had a moment of button confusion — the central play/pause/control button is marked with a thick raised dash, while the volume down button is marked by... a thin recessed dash. The difference looks clear enough when printed in the manual, but once moulded into black plastic, well, not so much. Also the Bluetooth pairing command is near unguessable — hold down both plus and minus volume buttons together for eight seconds. C’mon! And especially hard if you pick the wrong minus.

But first time you use them, they go into pairing mode automatically.

Such small ergonomic quibbles are removed by familiarity, and also because the ATH-M50xBT sounds simply marvellous. It’s a big and full and musical sound. They made Drive My Car (stereo remaster) sound rock solid and meaty. They dug out the depth and held out the hang of the big bass drum under the introduction of Hurricane from ‘Hamilton’, while the vocal sat crisp but not sibilant over the top. There’s the same combination of thrumming depth and edgy (here slightly sibilant) vocal on Birdy’s live Terrible Love, at the start of which the detail was sufficient for us to pick out words from a rather chattery pre-encore Opera House audience. Dion’s vocal on I Read It (in the Rolling Stone) tilted into peakiness — but that’s nearly the truth of it; it is a thin vocal recording, so we didn’t blame the A-Ts too much. A sweep had them sounding unbelievably smooth through the lower frequencies, from way down up to 200Hz, then a dip with the mids seeming backed off a little. Up top there’s no wide openness of blue-sky treble; of course that’s largely because these are closed headphones, and also that we were listening via Bluetooth. The result is fine indeed for a Bluetooth sound, and the most successful transition from an existing design to Bluetooth operation that we’ve heard.

They proved comfortable long term, except on a couple of 30-degree beach walks, where their big blackness raised a sweat. There’s bags of wireless level for general use, at home or for anywhere quiet. On bumpy bus rides we had enough level to drive modern recordings over the morning commute easily, but could have used a few more notches for older, quieter or less dense recordings.

As usual, switching to the cable can provide additional level. It also gave slightly improved solidity through better treatment of high frequencies. That peaky Dion vocal was bright but not offensive now, though lower male vocals — Leonard Cohen ‘Live in London’, Paul McCartney on My Valentine — went a little honky from too much low-mid next to a recessed mid-mid. It was a pattern: female vocals slightly thinned, low male vocals slightly honked. The deepest stuff remained very strong, supporting the sheer strength of sound delivered here, while the imaging and the musicality remained immensely enjoyable.

Conclusion
This is an entirely successful conversion of audio-technica’s strong monitoring headphone into a strong consumer Bluetooth headphone. It looks cool, it looks strong; its wireless sound is magnificent, and the price is very attractive.

audio-technica ATH-M50xBT wireless headphones
Price: $379

+ Entirely successful transition to Bluetooth
+ Full meaty wireless sound
+ Cable with inline controls

- Two minus buttons

Type: Closed over-ear dynamic headphones with Bluetooth including AAC & aptX
Drivers: 45mm with CCAW voice coil
Sensitivity: 99dB (cabled)
Impedance: 36 ohms (cabled)
Quoted frequency response: 15–28,000Hz (cabled)
Quoted battery life: 40 hours
Weight: 310g