These are not beryllium driver headphones. Slate has a FAQ page where you can find more technical details:spunkmuffin wrote: Sun Oct 04, 2020 5:49 pm Yes, the bit made from beryllium will be the diaphragm, which is the dome at the centre of the membrane. Most of the surrounding membrane is likely made from some clear polymer. The term 'driver' usually includes the magnet, pleated surround, diaphragm, coil, former, basket...the lot really. I am nitpicking.
I am very interested in these. It's the least expensive set of beryllium diaphragm headphones available, which is great. I'd like to know more about the equalisation, and how it's working. Thanks for the review bmanic, I trust your judgement and if they give a better window into the music than the headphones you've mentioned that makes them very attractive.
"The VSX hardware is a Beryllium metal-plated driver coupled with a neodymium driver assembly for unprecedented acoustic performance."
You can already find this being discussed on gearslutz, but VSX headphones seem to be rebranded RBH HP-2 headphones with custom modifications. There are other headphones in this casing that also come with "beryllium" drivers.
I put beryllium in quotation marks, because you can have only a tiny amount of beryllium used in your driver and still call it beryllium driver. But that is misleading, they only market their product around the name of a premium material.
RBH also marketed their headphones as beryllium headphones, but they at least tell you this:
"The HP-2 utilizes our 45mm diameter driver diaphragm that incorporates a beryllium surface that has been applied using a technique called, “thermal physical vapor deposition.” This micro-thin layer of beryllium provides an extended frequency response (10Hz to 40,000 Hz)"
"Micro-thin layer of beryllium", micro meaning that you can't even see it I guess
I came across people comparing VSX headphones to Focal Stellia, but Focal actually tells you that they are using a pure beryllium dome. If you would take apart this 3000$ headphones, you could hold this beryllium piece in your hand. Much different from a micro-thin layer that you can't even see 
And Slate dare to attribute the properties of using a pure beryllium dome to their product in their youtube video.
You can read more by looking at page 56 on gearslutz, then skip to page 61 - interesting disscusion started to roll in when Slates partner who was behind VSX hardware, joined the conversation to answer some of the concerns. He says specifically, twice even, that they developed the driver for VSX, including earlier prototypes. He says the driver was "engineered with the goal in mind".
He didn't bother reading through the whole thread and didn't catch that Steven Slate already said something different that contradicts him
When someone brought up M&O Beryllium Acoustic headphones, which look just like VSX, but are equipped with bluetooth, Slate responded that these bluetooth headphones are "probably" using a different beryllium driver (so it's possible apparently), because the one they use "is so new to the market" and "besides the Beryllium driver and casing, everything is custom".So the driver is not custom apparently. But I think it is no coincidence that there are other brands who used to or still do sell headphones that not only share the same casing, but also come in combination with beryllium drivers. RBH discontinued their product in 2018. I'm not sure, but I believe that they are behind this design. HP-2 went through some redesign process, but the dropped the project and never realesed it. Then rebranded versions started coming out (also with custom mods, like in case of M&O).
So I'm not sure if what is being told about how they designed these headphones has something to do with facts
VSX can still sound great tho. The sound quality and their software has literally nothing to do with anything I just said. In fact, RBH HP-2 had really good reviews, people seem to really like the low end in these headphones. That makes me wonder if Slates patent pending APS actually does something for the sound or they just use "patent pending" to make this product sound innovative (pretty common in marketing).
If the driver and casing are not custom, then they were not designed for this APS technology. So what exactly they had to do in order to make this work? laser cut 2 holes I guess. Sometimes simple and random ideas can give unexpected results tho.
