Focal Bathys MG Review: Evolution of Mg Precision

I have to admit my bias up front. I love Focal’s original Bathys (released in 2022), it’s become a favorite whenever I need portable headphones. Bathys came out at a time when many high-end brands released wireless ANC headphones, and each seemed to raise the bar on wireless sound quality expectations. Somewhere between the advanced higher bandwidth Bluetooth codecs and headphone designs featuring high quality drivers paired with futuristic sound dampening enclosures, each brand has surprised me by imparting some of its unique sonic characteristics through a wireless Bluetooth connection from a phone. Today, wireless convenience really can deliver a fair rendition of hi-fi sound quality. Bathys’ punchy power in its bass response paired with its refined dynamic range has made it my second favorite companion on long dog walks.

It’s been just two years since the release of Bathys and Focal already has a new entrant in the wireless ANC headphone space, Bathys MG. Thankfully Focal retained the strengths of the original by designing Bathys MG as more refinement than reimagining of a new flagship wireless headphones. But the one major change in Bathys MG answers a lingering question I’ve had; What would the driver from Clear MG sound like in a closed-back headphone? In Bathys MG we have one answer. 

Bathys MG Look, Feel, Style! 

What you’ll notice first about Focal’s new wireless headphones is the choice in color. Focal built Bathys MG as the wireless, closed-back expression of Clear MG, the passive open-back headphones that introduced Focal’s new magnesium driver to its line of high-end headphones. Bathys MG borrows shades from Clear MG’s color palette, resulting in a timeless copper that Focal calls Chestnut. 

The esthetic design is true Focal. The French speaker company likes to avoid designing the standard flat-black headphones with contrasting colored accents, a popular headphone design choice that often makes them look like a prop from a sci-fi movie. Instead, Focal designs aim to lend your head a touch of luxury and class. Original Bathys with its aluminum grey is a little closer to the movie prop than Bathys MG. Fortunately, Bathys MG didn’t forego the earcup’s backlit LED flame logo. Like original Bathys, users can set brightness or disable the backlight in the control app. It’s a silly feature that may use only a trivial amount of battery life, but I’m glad it's there even if I generally leave it off. I like knowing that a high-tech French audio company known for sophisticated design employs someone with the playful sense to put glowing LEDs on the sides of its wireless headphones.   

The structural and chassis of Bathys and its new MG counterpart are identical. Both use materials like aluminum and magnesium, real metals throughout the earcups, yokes and through the headband. Minimal use of plastic is included around the control buttons and locking mechanism inside the headband. It all comes together in a ruggedly durable pair of headphones, and I do mean durable. At 6’2” in physical height, but 5’8” in my own mind, I can rap my head on over-hanging objects with the best of ‘em. Fortunately, my original Bathys are no worse for wear from minor head bumps since 2022 and they remain fully intact. I expect no less ruggedness from Bathys MG.

No leather-bound box for Bathys MG! Focal's new Eco-Packaging is made from natural bamboo & sugar cane pulp

The one external departure from original Bathys may affect sound quality while enhancing Bathys MG comfort. Original Bathys leatherette ear cushions have been replaced with a softer genuine leather, cushioned by an even softer, cushier memory foam than its predecessor. The softness upgrade on MG is a welcome change and its real leather is even more breathable. The only potential drawback to all that luxurious comfort is the cushion may be a bit too soft for some. I’ve never had a problem with the clamp force of Focal’s headphones, but depending on your cranial circumference, any headphones could fit a little tight. The softness of Bathys MG earpads may draw the earcups closer to the sides of your head and for some this might cause inner-earcup contact with your ears which could be an annoyance.  

Updated Features

Focal’s new flagship wireless headphone has received a few incremental updates and at least one major upgrade that Focal feels has earned Bathys MG’s $1,299 asking price. That’s a price hike of $600 from original Bathys, priced at $699. If you take a look through the specs sheet you won’t find much on-paper difference between the two. One standout for Bathys MG is its updated Bluetooth to version 5.2 to offer multi-point connections that makes it easier to toggle between source devices, but like its predecessor, Bathys MG provides a 30-hour battery life.

Full View of Bathys MG

Bathys MG Vs. Bathys Comparison

The evolution of Bathys

Focal App: The Focal app provides the same controls for Bathys and MG. Toggle ANC between “Soft” (less ANC) and “Silent” (max ANC), both work reasonably well, but I wish Focal provided an option to disable ANC. The “Soft” setting is close enough and doesn’t seem to interfere with musical clarity, but we won't know that for sure until we can compare Soft with Off.

Bathys MG shares original Bathys’ “Transparent” button on the left earcup, away from the rest of the controls located around the right earcup, this allows relatively quick access. The button will immediately activate Transparent Mode so you can hear your environment through the microphones that Focal says have received improved positioning. Transparent mode provides a measure of situational awareness if you happen to be out for a walk and need to hear, fast. It’s a nice touch for personal security as today's wearable technology makes it all too easy to forget your surroundings. 

In-app EQ is unchanged for Bathys MG, a solid 5-band EQ that lets you save custom settings but makes available a few Focal presets including Home, Loudness and Focal’s house sound preset Dynamic is said to be coming via software update anytime now. I only tested Bathys MG flat. Dynamic is already available to original Bathys and it’s my go-to when using Bluetooth. 

Mimi Sound Personalization

Focal now participates in the trend of wireless headphone apps providing a non-medical “hearing test”. The app walks you through a few-minute test intended to find blind spots in your hearing so it can compensate for your difficult frequency ranges at volume. The Focal app uses a 3rd party app called Mimi that’s available for both Bathys and MG. After I take these “tests” I usually end up hearing some variation of too much treble, which drives me to disable it. But, I must admit that Mimi’s Sound Personalization seems to work better than most, or at least any I’ve tried, it seems to work nicely with both Bathys and MG.  

As we get older, having lived a life involving many live rock and electronica performances, we may experience some erosion to our perception of high frequencies. C'est la vie. For me, the effect of activating Mimi’s Sound Personalization is subtle, it seems to be restoring some of the missing highs in my hearing but only enough to add a sense of depth and detail to the sound, further defining separation between instruments for slightly improved imaging. Thankfully, it doesn't simply turn up the treble. The app provides a slider so you can raise or lower the intensity of the Personalization effect.  

Bluetooth Codecs

One of the best benefits of using an Android phone is access to advanced, higher bandwidth Bluetooth codecs. Unfortunately, iOS-users are still stalled at the AAC codec that peaks at 320-kbps. But for Android users, both Bathys & Bathys MG will let you take advantage of Qualcomm’s aptX Adaptive, a high-resolution BT codec that delivers a peak data-rate of 420-kbps at 24-bit/48-kHz. Fortunately both Android and iOS users have access to the mode providing the best sound quality possible from Focal’s wireless headphones. More about DAC Mode later. 

Despite the high-resolution of aptX Adaptive, all Bluetooth codecs are compressed in some way. The arguable exception is Qualcomm’s newest aptX Lossless that can deliver up to 1.2-Mbps at 16-bit/44.1-kHz, but still just .2-Mbps shy of a real lossless, CD quality stream that uses up to 1.4-Mbps of data. But Qualcomm reports that it’s found a way for its compression algorithm to deliver lossless audio at a slightly lower data rate. Unfortunately, not for Bathys. 

I’m a little disappointed that Bathys MG didn’t get the upgrade to the aptX Lossless, but I can understand not making that jump. Compatibility with Qualcomm’s "Lossless" BT codec probably would have required Focal to make changes to its Bluetooth infrastructure for compatibility to the Snapdragon Sound ecosystem, and then only to benefit a small subset of the subset of Android users. Snapdragon Sound mobile devices are still relatively rare, but I would have appreciated Focal using the LDAC BT codec and its peak stream of 990-kbps codec as an alternative. But anyone who wants real uncompressed lossless and high-resolution sound is already using Bathys & Bathys MG in DAC Mode. 

So, with BT compatibility the same, that leaves the BIGGEST difference between Focal’s wireless headphones and the hardware centerpiece of Bathys MG. The driver with a pure magnesium membrane.

Focal Driver Evolution: Aluminum to Magnesium  

Since 2016, Focal has built a veritable high-end headphone empire on its dependably high-quality aluminum/magnesium m-dome driver. It started with Elear, the high-end yet mainstream targeted headphones released alongside its first flagship $5,000 headphone, Utopia. The result of years of research and development, Utopia employs an exotic Beryllium M-dome driver while every aspect of the open-back headphones were purpose built to be as close to perfection as possible. The 40-mm driver inside Utopia was adapted from the tweeter found in some of Focal’s most exotic loudspeakers that could cost as much as a sports car. Utopia achieves the ultimate in sensitivity and detail through the Beryllium diaphragm that’s said to be only 75-microns wide, in a driver that combines for an astonishing weight of only 135-milligrams.  

Fortunately for the rest of us, Elear, Clear and many more headphones to come would be priced considerably closer to mainstream consumer budgets through its use of the aluminum/magnesium (Al/Mg) driver instead of Beryllium. Outside the drivers, Focal’s line of Al/Mg headphones all benefit from the same advances in headphone acoustics that Focal achieved building the Utopia. 

Lightweight yet strong, aluminum has been used as a driver material in many great loudspeakers and headphones. But Focal pushed the sonic limits of aluminum alone with its Al/Mg alloy using only 10% magnesium. The Al/Mg driver is also used in some of Focal’s more accessible loudspeakers because it strikes a balance between rigidity to combat distortion but lightweight and sensitive to the minute electrical impulses that create detailed sound. Focal says its patented m-shaped dome diaphragm extends the surface area of the driver itself and the open space inside the headphone’s earcups. These properties add up to a line of headphones known for incredible detail, dynamic range and a punchiness that swings for the fences. Focal brought a similar R&D cycle to perfecting the closed-back headphone. Focal built a no-compromises closed-back and named it Stellia, complete with Beryllium driver and a $3,000 price tag. Just like their open-back counterparts, Elegia and Radiance and more closed-back headphones were all priced closer to mainstream affordability than Stellia, the crucial difference being the Al/Mg driver instead of Beryllium. 

Before Focal introduced Bathys' new slim form factor with swivel earcups that can lie flat, Focal’s line of high-end headphones were known for being a little bulky compared to competitors. But the French speaker company’s closed-back headphones used the bulky space inside the ear-cups to achieve unheard levels of sonic isolation. A system of dampening cells were developed for the inner earcups of Stellia to reduce sonic reflections while acting as passive noise cancelling. The same isolation and dampening technology has been used in all of Focal’s closed-back headphones ever since, including in the new compact form factor used for Bathys and Bathys MG, but at a slightly smaller scale. 

The 100% MG Breakthrough 

In 2021 Focal launched Clear MG and the debut of a new headphone driver with a 100% magnesium diaphragm that brought performance surpassing its Al/Mg counterpart. Magnesium is an interesting element for a driver. It has slightly lower yield and tensile strengths than aluminum, which would make magnesium a little more difficult to shape into Focal’s M-dome driver and probably why it’s more expensive. But for the effort, magnesium offers a better strength-to-weight ratio. So, for the same amount of strength and rigidity as aluminum, Mg will be thinner and lighter, carrying less mass gives the Mg diaphragm faster transient responses than aluminum and superior damping properties to suppress unwanted resonances that result in distortions.

Focal MG driver exploded

The sonic effects Focal was able to achieve with its new pure magnesium driver places it somewhere between its Beryllium and Al/Mg drivers. If you haven’t heard Clear MG, its sensitivity is stunning and may be the headphones that even hi-res audio skeptics might say warrants a high quality studio master at 24-bit/96-kHz.

Bathys MG Subjective Sound Quality 

As much as I love the results from many of Focal’s headphones that use the Al/Mg driver, the benefits of the new pure magnesium driver in Bathys MG are tangible. I took a comparative listen to both original and MG using aptX Adaptive with a flat EQ and no Mimi Sound Personalization. Bathys MG shares the original’s overall warm tonal character and punchy dynamic range. The subtle differences in detail is especially noticeable on the higher end, upper midrange and treble and when I listen specifically for sonic imaging, the difference becomes especially tangible. 

I put on Philadelphia's melodic indie rock band The War on Drugs, Tidal’s lossless recording of Under The Pressure with all of its unique instrumentation. Guitars, paino and even the feedback that blends into the song's intro and outro all sound layered and spacious in way that was noticeably just a cut above Bathys. Generally, these attributes aren’t an easy feat for closed-back headphones, Bathys MG provided space that lets you close your eyes and localize each instrument. The soundstage isn’t especially wide, even for a closed-back, but clear sonic imaging compensates with a strong sense of depth and space. 

After toggling back and forth between original and Bathys MG, as great as original Bathys sounds, the advantages in imaging and detail are just a small cut-above using Bathys MG.

When turning it loud for a track to exercise bass response, what better song could there be than Underworld, River of Bass? Electronic low frequencies are layered on this track with a lot of simultaneous activity from sub-bass to lower-midrange. Bathys MG didn’t flinch, even at higher volumes. This is a song where original Bathys' one weakness in being a little forward in the upper bass range becomes an asset, it’s just a fun song to hear on Bathys with all of its meandering bass tones and random sound effects beneath the constant rhythm. Bathys MG brings a thickness to the bass, especially the drum beats while taking nothing away from the choppy upper-midrange voices in the song that sound as if they’re cutting in and out, it's as if Underworld's producer dared you to be annoyed. Still, a fun song and musical style to hear on original Bathys, even if it doesn't sound as accurate to the original recording as it does on Bathys MG.    

Overall, the result in my own subjective comparative listening is that Bathys MG provides a little more detail and slightly better imaging at similar levels of punch and slam achieved by the original. Original Bathys was going to be a tough act to follow, and Bathys MG makes for a suitable evolution of the original. 

There’s a reason why I like to refer to Bathys and Bathys MG as “hi-fi headphones with wireless capability” and not just “wireless headphones”. DAC Mode. As mentioned earlier, I'll often use Bathys in DAC Mode on go-to for long dog walks outdoors, it has largely superceded my previous but less convenient portable hi-fi rig. I find I don’t use my older system as much anymore, it includes an iFi xDSD Gryphon DAC/Amp using a balanced 4.4-mm TRRRS connection to my closed-back Focal Radiance with its excellent 40-mm Al/Mg driver. It's still a great system, but it's easier to just plug-in DAC Mode on Bathys.

Radiance positively radiates classic rock and metal. Bathys DAC Mode simplifies the "high-end portable headphone rig".

Bathys MG DAC Mode

DAC Mode works the same on both models, accessed on Bathys and Bathys MG using the right earcup switch that features: Off - DAC - On. Use the middle position "DAC" when connected between smartphone (or other streaming digital source) and the headphones using a USB cable. I mostly use an Android phone using USB-C-to-USB-C. Access your favorite streaming app or if you have some locally stored music or have some locally stored music on a NAS over wifi, the USB Audio Player Pro app will detect the headphones and playback everything in bit-perfect purity from a local storage or network music library. Bathys MG DAC will decode the raw stream at lossless or hi-res up to 24-bit/192-kHz using Focal’s undisclosed DAC. I’ve asked Focal in past and apparently the precise DAC is a trade secret. But given the French speaker company’s close ties with British high-end audio company NAIM, they’re not wanting for expertise in the construction of a DAC/Amp. The results are stunning! 

After listening to the aforementioned songs over aptX Adaptive, I switched over to a locally stored lossless 16-bit/44.1-kHz copy of 1994 trip-hop album by Massive Attack, Protection, the title track featuring Everything But the Girl's Tracey Thorn. As good as aptX Adaptive sounded, DAC Mode really delivers the extra detail in every thump of the bass-line. Each hit of the deep electronic tones, key of the piano and breathy vocal of Thorn. I hear the edges around each boom of the repeating bass-line and its unique characteristics through its decay-time cycle, from start, peak and finish that clears before the next boom. The clear separation in these details that come alive in DAC Mode just aren't available in Bluetooth. It's my humble opinion, DAC Mode makes Focal's portable ANC headphones transcendent.

Conclusion 

Focal Bathys and Bathys MG are both great headphones - period. No headphone can ever be perfect, but the original Bathys seemed close to perfect as I'd ever heard in a portable, wireless headphone. Fortunately, Bathys MG didn’t stray too far from the original Bathys formula. Bathys MG introduces a refinement in detail, imaging and the added comfort of softer, real leather earpads that make it a tangible but slight upgrade. I don’t see anyone prioritizing Bathys MG's improved microphone placement or BT 5.2's multi-point Bluetooth as a deciding factor in buying or upgrading. But if you’re reading this you’re probably mostly interested in sound quality. If you’re already a proud owner of original Bathys, I personally wouldn’t run to upgrade to Bathys MG, unless you’re a completist with an extra $1300. No doubt, the price is high. But if you really want a justification for making your first foray into a Focal wireless headphone... Don't think of Bathys MG merely as a portable, Bluetooth headphone. 

Bathys and Bathys MG's DAC Mode raises Focal’s wireless line to a true hi-fi enthusiast product category rather than just another pair of Bluetooth headphones. For the hi-fi headphone enthusiasts among us that are known to use separate DAC/Amp accessories with our favorite passive headphones, Bathys MG makes a compelling case for a one-stop portable hi-fi experience with an excellent built-in DAC & Amp that you’ll use in both DAC Mode and Bluetooth.

Bathys & Bathys MG, case is included

So, if you’re in the market for high-end portable closed-back headphones that adds the flexibility and convenience of wireless mode, Bathys MG could be seen as a relative bargain. Bathys MG is Focal’s first closed-back headphone to feature its 40-mm pure-Mg driver. The driver puts it second only to Stellia in its closed-back lineup. Bathys MG brings a fair rendition of Clear MG’s ($1500) detail and imaging to a narrower soundstage, along with the tighter bass response and sonic privacy of the closed-back form factor. Plus, you get all of Bathys ($700) wireless and portable capabilities that easily fits into a backpack or carry-on luggage. It's a portable, multipurpose headphone. 

Bathys MG continues Focal’s foray into true hi-fi & wireless headphones, it's not a complete overhaul, just a tangible step up in certain aspects of sound quality built on the original Bathys formula. Considering the new frontiers in wireless technology on the horizon, I suspect Focal isn't finished delivering excellent wireless headphones. After hearing how good Focal’s new Mg driver sounds in a closed back, I also suspect a Focal high-end passive closed-back headphone with MG in the title will be coming sometime in the near-future.