Reviewed on: SoundStage! Solo, November 2022
I measured the Focal Bathys headphones using laboratory-grade equipment: a GRAS Model 43AG ear/cheek simulator/RA0402 ear simulator with KB5000/KB5001 simulated pinnae, and an Audiomatica Clio 12 QC audio analyzer. A Reiyin WT-HD06 Bluetooth transmitter was used to send signals from the Clio 12 QC to the headphones, and for the USB input measurements, I connected the headphones directly to the computer. For isolation measurements, I used a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface. These are “flat” measurements; no diffuse-field or free-field compensation curve was employed. If you’d like to learn more about what our measurements mean, click here.
This chart shows the Bathys headphones’ frequency response with the wired connection in Silent mode. There’s an unusual bump in the response centered at 500Hz (which I didn’t notice in my listening tests), less energy at 2kHz than we usually see, and a lot of treble energy between 2.5 and 8.5kHz (which I did notice in my listening tests).
This chart shows the difference in response between the Bluetooth connection, the DAC (USB) connection, and the wired connection, all in Silent mode. There’s basically no difference. You can see a bit of a dip in the bass with the Bluetooth measurement, but that may be because I had to gate it more aggressively because of the added latency. Although it’s not shown here, the response was not affected when I switched noise-canceling modes, which is impressive—most headphones show some change in response in this case.
This chart shows the Bathys headphones’ response in wired mode with ANC on compared with the Mark Levinson N⁰ 5909 (which are said to be very close to an ideal Harman curve response), the DALI IO-6, and Apple AirPods Max headphones. There are a lot of very different-looking curves here, and the Bathys headphones sit somewhere in the middle. Probably not a bad thing.
The Bathys headphones’ right-channel spectral-decay plot (measured with the wired connection) looks clean, with no significant resonances.
Here’s the THD vs. frequency, measured using the wired connection in Silent mode at 90dBA and 100dBA (both levels set with pink noise). The distortion’s a little high in the midrange, but as it doesn’t rise with output level, this might be an artifact of the latency in the digital signal processing. The distortion in the bass is real, because it rises with output level. However, considering that 10% THD is a generally accepted threshold of audibility of bass distortion, I doubt it’d be noticeable.
In this chart, the external noise level is 85dB SPL (the red trace), and numbers below that indicate the degree of attenuation of outside sounds. The lower the lines, the better the isolation. The Bathys headphones are competitive with some of the best noise-canceling headphones on the market. That’s impressive—I might expect a high-end brand that sells mostly on sound and reputation to just slap a noise-canceling chip in there and call it a day, but they really worked on the noise canceling here. (This is with all models set for maximum noise canceling, by the way.)
This chart shows how the different noise-canceling modes in the headphones compare, and what the passive isolation (with the headphones turned off) looks like. This is about what I’d expect from these modes.
Latency, measured with the Reiyin Bluetooth transmitter in aptX mode (my transmitter has aptX Low Latency, but not the aptX Adaptive codec included in the Bathys headphones), in DAC mode (USB connection), and wired mode, averaged about 285ms, 110ms, and 38ms, respectively.
The impedance magnitude, measured in wired mode with power on, measures 1530 ohms, and the phase is flat. This is typical of active headphones.
Bottom line: The Bathys headphones’ measured performance is generally excellent. The noise canceling is nearly world-class, and the frequency response looks pretty normal, although the measurement does seem to confirm my impression that these headphones sound a little bright.
. . . Brent Butterworth