Headphone Reviews

Bluetooth headphones have brought me joy for years—sometimes a little too much. Once, while waiting for a flight at my regional airport, I switched on the active noise cancellation, closed my eyes, and got so sucked in by Elvis Costello's album Imperial Bedroom that I didn't hear the boarding calls. It was no fun texting my client that I'd missed my flight. I fibbed that I'd been stuck in traffic, because blaming Costello for delivering such an immersive triumph would've been uncouth.

Kind of blue
For all their convenience, Bluetooth headphones and earbuds have fundamental problems. Take their batteries (please). They're only fully rechargeable 300–500 times, which means that after just two or three years of moderate-to-heavy use, most people toss their depleted wireless ear-fi in a drawer and buy a new pair.

The regular, non-Bluetooth 'phones I find the most captivating are open-backed planar magnetics like my Audeze LCD-4 and HiFiMAN HE1000se. That means I'm out of luck when I travel, because those cans are big and dorky-looking, and the planar Bluetooth products I'm aware of are all closed-backed. That's understandable—indeed essential—due to the need to block out high levels of background noise, and because in public, your music shouldn't bother others.

More problematic is that the Bluetooth codec is only capable of playing lossy, worse-than–CD-quality files (footnote 1). Not even Bluetooth 5.3, the latest version, supports lossless audio on its own, although chip maker Qualcomm has a Snapdragon microprocessor that allows the playback of hi-rez files within the Bluetooth standard (footnote 2).

Among the first to take advantage of this option was Edifier, the Chinese mid-fi brand, which offers an honest-to-goodness Bluetooth planar headset, the $400 Stax Spirit S3. (Edifier bought Stax in 2012.) The company says that the S3 supports hi-rez music up to 24/96. That ticks an important box for me. But the S3 has no active noise cancellation or customizable EQ. I consider that a shot and a miss. Bluetooth headphones are made for being out and about, including on planes, so ANC isn't optional.

I'd like to be under the sea
With the Bathys, French high-end company Focal took a different approach to bridging the quality gap between Bluetooth cans and wired ones. The $699 Bathys can be enjoyed with or without a cable. Plugged into a music source, the headphone's built-in DAC supports PCM audio up to 24/192.

The name Bathys (team Focal pronounces it Bah-TEECE) comes from bathyscaphe, a 1930s deep-sea submersible, and is intended to conjure the kind of stillness you might find if you journeyed beneath the waves (footnote 3). A trip to the ocean's depths in a hollow steel ball less than 5' in diameter doesn't sound super relaxing to me, but I like the pretty name; and thanks to its onboard ANC, it does provide a sense of ease and calm.

The Bathys's silver-accented design is on the blingy side but keeps things classy. The headphones are slightly bigger and probably draw more attention to themselves than most over-the-ear wireless competitors, such as the $999 Mark Levinson 5909, the $699 Bowers & Wilkins Px8, or the $1600 T+A Solitaire T.

Focal's designers placed the main controls along the rim of the right cup, where your thumb naturally finds them. Near the headband yoke is a springy volume-up-and-down rocker switch, centered by a small multifunction button that you long-press to pair the Bathys to a playback device via Bluetooth. After that, the button is a pause/play toggle when you press it once, and a next- or previous-track button when you hit it two or three times respectively. If a call comes in, a quick press of the same control lets you take it; a longer press sends the caller to voicemail.

Further down the bezel is a three-way power switch. Flicking it from off to on connects you to one of up to eight devices you'd previously linked to the Bathys—whichever one is active and closest. You select the third (middle) position, marked DAC, when you connect the USB-C cable to your portable source. Then there's a small round button that summons Amazon Alexa, Google Assistant, or Apple's Siri—your choice.

Finally, a single switch on the left earcup offers three options, starting with maximum or medium noise cancellation. The third choice is transparency mode, which lets you keep an ear on your environment without turning the music off. That's good if you're having brief conversations in meatspace, and for staying alert to traffic when you're out enjoying your tunes.

In the white room with black curtains
I found the Bathys more comfortable than most headphones I've tried. For my largish head, it has just the right amount of clamping force and earpads that create a tight enough seal for the bass to remain solid and consistent even when walking briskly.

The Bathys's black-on-black plastic buttons don't feel substantial, but they get the job done. The Focal logo on the earcups is backlit, which is cool, but I'd prefer the power switch to be lit up. That way, before donning the 'phones, you could tell the right channel from the left in a dimly lit space. As it is, even in decent light, you have to feel along the cups' ridges to locate the (right-hand) side that sports the buttons. Competitors like B&W and Bose print a large R and L on the fabric inside their earcups. I ended up sticking a piece of thin bright masking tape on the Bathys's right yoke—not pretty, but pretty handy.

By the way, in the Focal-Naim smartphone app, you can dim or turn off the backlit logos I mentioned. The dimming function was introduced in a firmware update. Focal is good with this: Even just during the three months I spent with the Bathys, it got better thanks to several over-the-air improvements.

Another example is the Mimi hearing test, which became a Bathys feature last September. Mimi measures the acuity of both ears separately via a series of fading beeps at different frequencies. The moment you can no longer perceive the sound, you release an on-screen button, and so on through the audio spectrum. After about five minutes' worth of testing, Mimi applies a digital profile that aims to correct your hearing deficiencies. Think of it as an automatic EQ , no slider-fiddling needed. (The app also has a separate EQ function though, if that's your preference.)

Neither the idea behind Mimi nor the technology are particularly new. In late 2017, I bought a $175 pair of Bluetooth headphones from a company called Even. The H2s, which Even touted as "glasses for your ears," came with very similar hearing-correction tech built into the right earcup. The resulting "earprint" added a little pop and sparkle. Mimi does too, but better, because it measures a wider range of frequencies. And where the Even fix was either on or off, the Focal app lets you adjust Mimi's proposed correction from one to 100. For me, the 15–20 range yielded the most enjoyable result. At higher settings, cymbals and violins often sounded too sharp, and voices occasionally bore some gauziness, as if they'd been processed with a slight phaser effect.

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Footnote 1: The compact disc is 42 years old; Bluetooth, almost a quarter-century. That they're still natively incompatible in 2024 shows that technology doesn't necessarily move at the breakneck speed we think it does!

Footnote 2: To clarify how all this fits together: Bluetooth itself is a technology of wider scope. Audio codecs are part of the Bluetooth package. The default audio codec—supplied with every Bluetooth installation—used to be terrible but is much better in recent Bluetooth versions. This default codec, though, is supplemented by several proprietary codecs, including those from Sony, Apple, and Qualcomm. For an audio codec to be useful, it has to be supported by both the sending and receiving device. Apple devices, to cite an example, support only their own "AAC" Bluetooth—plus the default Bluetooth audio codec.—Jim Austin

Footnote 3: If I were French, I'd have preferred a name inspired by my homeboy Jules Verne's Twenty Thousand Leagues Under the Sea—such as Nemo, the submarine's captain, or Aronnax, the narrator and scientist. After all, the original bathysphere was developed and manned by a couple of Yanks: William Beebe and Otis Barton. See atlasobscura.com/articles/bathysphere.