When Fatboy Slim named his record You've Come a Long Way, Baby, it was in no way referencing the technological evolution of headphones. Dated references aside, for some reason that album was the first thing that popped into my head when I cast my mind back over Sony's audio journey from the late 70s to the present day.

Continuing Sony's progression through the audio ages, the WH-1000XM4s are the freshest Sony headphones on the market. These XM4s are the successors to the WH-1000XM3s and in my original writeup about the XM4s I suggested that they 'might just redefine smart audio'. And you know what? They are pretty darn smart.

Build

My review kit included the grey XM4s, a flight adapter, USB-C charging cable, a functional grey carry case, and AUX cable.

The headphones are made of high-quality plastic, with flexible padded earcups that twist to fit into the case. They're fairly weighty at 254g, so if you headbang a lot you might find that they move around quite a lot - or they might fall off your head.

The earcups can feel a little stuffy after hours of use, so let your ears breathe regularly. The protective case is made of reasonably sturdy fabric-covered plastic – look after the headphones and your case, and you'll be fine.

How they work - features

I'll briefly translate Sony's minimalistic, visual approach to user instructions: Tap the right earcup two times to pause/play, swipe up – volume up, and vice versa.  Swipe left to jump back a track and right forward. Tap the right earcup twice to answer a call, and twice to end a call.

One of the defining features of these headphones is Speak-to-chat. It's an awesome feature that will pause the music if it hears you speak, and then use the microphone to amplify your voice, as well as the voice of whom you are talking to.

This was a feature I was most thrilled about – and it works a gem. You still have to say ‘sorry? Could you repeat that' (or some variation thereof) because you missed the first thing someone said to you, but it means you don't have to constantly remove the headphones or pause the music.

There is a downside though – if you have a habit of singing along to your favourite tunes, you might want to turn speak-to-chat off. There's nothing like your headphones turning off when you get swept up in the chorus of your favourite song.

Sony has finally incorporated multipoint Bluetooth 5.0 connection into its headphones, which means you can connect to two different devices at the same time.

Sony also says the Bluetooth range is around 10 metres – I managed about 16 metres outside one end of the house before sound cut out, and just seven metres outside the other end in the house.

The headphones also have a sensor that turns the music off when you remove the headphones. It's a useful feature that can help to preserve around 30 hours of battery life with noise cancelling on, and around 200 hours with noise cancelling off.  Charging from flat to full takes a few hours.

Sound

Sony's DSEE Extreme sound engine is the successor to DSEE HX. That means a dash of AI in the processor will try its best to upscale music to the highest resolution possible – with varying results, but generally, I found it to significantly improve even the most terrible 128kbps MP3 files.

Unsurprisingly the sound quality across low, mid and treble tones is excellent, with a range of 4-40,000Hz. I couldn't fault these when it came to music, playing games, or watching TV shows on Netflix.

There is one major drawback to the XM4s: External noise bleed. When the volume is either loud or medium. I couldn't find a way to fix this, and it's super unfortunate because for me it is a major blow to what is otherwise a good pair of headphones.

I found the microphone to be of average quality, after testing through Zoom and Hangouts. You'll get clearer sound through a dedicated business or gaming headset but the sound isn't too bad.

Sony | Headphones Connect app

I've mentioned Sony's headphones app in my review of the WF-1000XM3 earbuds, but there are a couple of notable features associated with the XM4s – namely, the ability to turn Speak-to-chat on or off, and The ability to connect to two devices simultaneously (e.g PC and phone). You'll know if this is working if you hear a voice say Bluetooth second device connected.

The voice assist function can be programmed into the Custom button on the left earcup so you have direct access to Alexa, Google Assistant, the Google app, or Siri.

I won't go into the other features in great detail, but you'll find adaptive sound control that detects if you're walking or running or sitting down, noise-cancelling optimisation, ambient sound control, the equaliser, battery life, and other settings.

Verdict

At around $500, these headphones are available in black and grey. They are a fantastic piece of kit with good sound and good tech. Noise bleed was an issue for me but if you don't mind noise escaping the cups and carrying the tune on the wind, the XM4s are worth a look.