Focal Bathys Wireless HiFi Headphones with Active Noise Cancellation - Official Discussion Thread

Maybe @Immersive_Sound_Tech can chime in and tell us if you still don’t hear a noticeable difference between those two OTG options?

That’s interesting. Is there a technical explanation as to why that’s the case? A loss in signal quality?

Sebastien, you are definitely asking the wrong guy. The quality of the OTG is really very good. But I consistently heard a small but meaningful difference. I wonder if that experience might change from OTG cable brand to brand.

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I certainly have no idea as to the specific cause, but variation in sound quality between different cables is definitely real, so from a super high level, I wonder if the 3rd party OTG cables simply aren’t very good. Usually it’s not so much an issue with 1’s and 0’s, but other junk that somehow makes it into the signal (or doesn’t get drained out).

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I redid my comparison of the Apple Camera Adapter and Meenova lightning->USB-C cable, this time I used a higher-quality and shorter USB-cable with the Apple adapter.

Sturosen is spot on with his description, the Meenova cable makes the sound stage a tad less vibrant, less detailed, and the stereo panorama is not as coherent. We are talking small differences here, but with a pair of headphones with this level of clarity, it is audible.

Also, the low-end becomes a little less defined and woolly, but don’t read too much into the ‘woolly’ part, because I’m splitting hairs really.

Interesting, I am a ‘cable guy’ and it never seize to amaze me what cables and connectors can do to improve the sound quality (or rather, have a less detrimental effect on the sound).

If I allow myself to speculate, maybe the Apple Camera USB-adapter acts as a ‘buffer’ between the iPhone and Bathys headphones. I wonder if that might have a positive effect on the sound quality. But I have no knowledge of the actual design to back that up.

Sturosen, thanks for pointing me in the right direction and redoing my test. :+1:

Guess it’s back to using the Apple Camera Adapter then.

I wonder if there’s any portable products on the market to isolate two USB units - like an iPhone or laptop, and a pair of USB-connected headphones?



It certainly makes me happy I wasn’t imagining the small differences. Thanks for weighing in!


Thanks, guys. Appreciate the context, and no worries! Good to know.

Since you guys do have such excellent hearing capabilities, would you be so kind and tell me if you hear a sound difference between the USB-C from the Mac/Laptop and the Apple-Car-Kit from the iPhone?

I don’t have both setups to compare - sorry!

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For those willing to use EQ APO, give this a try and let me know what you think:



This is pretty similar to my own EQ settings, except I don’t have as much sub-bass boost and I keep fluctuating my 900 Hz boost from 1-2.5 dB haha. Overall I can recommend this profile.

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@Sturosen @Immersive_Sound_Tech

So I am curious how there could be any difference in quality in the OTG solutions you were comparing. I am a low level digital guy that does reverse engineering of wireless and USB protocols. While your claims of differences in cabling definitely a place of the analog world, it is just not the same in the digital world. Any loss of single bits would cause a corruption of the USB control packets resulting in either a USB data disconnection or possibly a retransmission depending on the usb client coding, both most likely resulting in pauses or complete failure of communications. If you were hearing continuous music through headphones in DAC mode, then all of the bits are making it through the OTG cable to the DAC built into the Bathys, and therefore should be identical.


I’m with you and personally have little faith in digital cable upgrades. However, the quality and accuracy of connectors varies in the real world. Sometimes those tiny, tiny little electric pads don’t line up with a socket or don’t receive even pressure. This applies to simple TRS analog jacks and sockets too. It follows from out-of-spec products and stacked errors. Sometimes a molded plastic cable cover is too long or too thick to fit in a similarly bad plastic socket surround.

Over the years I’ve experienced nothing but errors and degradation with every USB cable over 2 meters long. Poor connector designs may result in marginal connections and thereby simulate the digital errors typical of a long USB cable.

Beats me, but that was my experience twice, months apart, and (to the extent listener bias is a factor) really wanting the OTG solution to work for me.

I wouldn’t argue against your far more informed position, but I do know what I heard. Twice.

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One would think so, and I expect that for short runs your analysis is correct. I’m one of those who is rather skeptical of many cable claims, and like @generic pay attention to quality of connectors.

That said, even in “digital” cable, there are not little zeros and ones passing through it. There are not even electrons passing through it. It is a signal, not that different from other signals. And I’m beginning to understand that it’s not even precisely through the wire, but in a magnetic field along the wire. And that is subject to a number of different real physical constraints and conditions. Not only resistance, but capacitance, materials, and other physical factors can play a part, particularly over longer runs.

What gets through that cable still has to be recognizable as an on or off bit by the hardware at the other side. This is not at odds with your description of packet corruption.

Not being a physicist, or even an EE, I am not being precise, but there is a lot on the subject of electron vs energy flow. Like Here. So this is what makes me open to thinking that there may be something not always considered when discussing cables.


Thanks for this! This is super helpful and gives me more context on how these things work.

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I wish this were the case, and I started with some deep skepticism in this hobby regarding digital cables and power cables being able to make a difference, but trusting my ears has completely changed my mind. In a resolving-enough system, not only is it possible to pick out differences, but they can be rather obvious.

I am not an engineer, but have done hours and hours of reading and watching on the subject, and the most basic points I can make are that it’s not simply about bits making it through to the other side uncorrupted. You’re right - it’s quite rare for a 1 or 0 to be misinterpreted in the amplitude domain, but it is frequent for there to be issues in the time domain which are not relevant in non-audio applications. In almost all other applications, if the bit makes it across in the correct order, you’re good. In audio, femtoseconds matter.

Additionally, there can be DC interference that rides along on digital (and other) cables which ends up polluting the sound as it goes from component to component. The bit can make it through just fine, but at the end, you’re just listening to voltage swings moving a driver, and if you have dc interference riding along, that’s going to change what the driver does, even if the bit was correct.

Hans Beekhuyzen has a super informative YouTube channel that discusses such issues from both a subjective and objective perspective. Here is a good video to get you started.

At the end of the day, people who are extremely skeptical tend to have never had the opportunity to just try it in real life, and if you’re in that camp, I can’t recommend anything more than hearing it for yourself. Find a friend or a showroom that has different cables on hand and demo it. We may not always know why a certain component makes a difference, but the differences are often so obvious that they’re impossible to deny.


Hi guys!

Just tried the Sennheiser BTD 600 adapter on my andoid phone (s22) to get atpx adaptive out of it with the Bathys. Its really small and works like a charm. A clear step up in audio quality!

It also remembers the last connected so its verry smooth just plugging it in the laptop as well to get atpx adaptive out of it as well.


Is there something similar for iPhones?

That was a good question. Looks like there is, even APTX-HD

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