Thank you for the explanation sir!
If I understand it correctly:
- TRRS is the plug of the common stereo plug found in most cans/iems in the market and usually 3.5mm (?)
- There are cans/iems that are factory-built with 2.5mm TRRS jack (what specific brands/models are the good ones?)
- There are cans/iems that terminates with 4-pin XLR male (what brands/models are the good ones?)
If my headphones/IEMs have the common 3.5mm jack (example: Bose QC25, Shure / Jays IEMs, etc.) can I still use them with the X1's balanced output? How? Or am I stuck with the X1's 3.5mm output?
Thank you very much for the information and sorry for the noob questions.
"TRRS" actually refers to Tip-Ring-Ring-Sleeve, which in very simplified terms means you'll see the 2 circles (or rings or notches or whatever) on the jack. For 3.5mm this is more commonly used for something like an in-line microphone or for in-line audio controls - you'll see this pattern on the jack for IEMs with microphones. I'm not sure if anybody actually uses 3.5mm TRRS for balanced audio.
As for any headphones/IEMs that come with 2.5mm TRRS, to be honest I can't think of any right now. There might be some out there, but I don't think it's very common. I think most people have to get 3rd-party cables to get 2.5mm TRRS terminations.
Yes, there are some headphones that come with 4-pin XLR cables, but they're usually very expensive. For example, off the top of my head I can think of the Hifiman HE1000, Audeze LCD-X and LCD-3, Sennheiser HD800S, etc.
As for whether you can use your headphones with the X1's balanced output, that really depends on the headphone. First off, if the cable isn't detachable, it usually isn't impossible but it will require some work to make them balanced.
If the cable is detachable, then you have different possible scenarios. To cover some of the headphones you listed, first I don't think it's possible to make the QC25 balanced without serious modification. This is because you can only plug in a cable on one side, and that connector probably isn't wired for balanced operation.
As for Shure IEMs, I think for the Shure SE215 and up the cables are detachable and you'll find plenty of 3rd party cables that fit them. So no problem there.
As for "Jays IEM", I'm assuming you're talking about the Q-Jays? They seem to use SSMCX connectors, and I couldn't find any balanced cables for these with a quick search on Google. But I think you could probably ask someone to custom-make these cables for you.
Hope this helps!