I’ve just got myself a pair of Sennheiser IE 500 Pros with the optional Bluetooth module.
Chopped the 3.5 mm plug off and soldered on a 4.4 mm Pentacon balanced plug and use it with a balanced output Moondrop Dawn USB-C DAC on my phone.
Also got a 4.4 to 4-pin XLR for use with my fixed headphone amps.
Really enjoying the sound from these and the foam tips provide great sound isolation. The Mrs. can’t hear my music and I can’t hear her TV! 
Using some old AKG K702 cans and a used Chord Mojo (the orig) and it’s wonderful. What’s amazing to me is that I’m hooked up via optical to a raspberry pi 4 with a HifiBerry card, and it is getting the stream from my Roon Rock NUC (which is in my basement on Ethernet) via WiFi !! So futuristic at least to me 
If I only had a Chord Poly to go with my mojo I would be unthethered (in more ways than one 
). They seem to be rare on the used market.
Due to builders dust my Head-Fi setup is stashed away. Leaving me with AirPod Pros 
They are really good at isolation, best of all iems I have had. Didn’t know there was a bt module might check it out. I recently bought the Momentum 4 for the ANC on the go, but I has to say the ie300 actually perform better in some scenarios than ANC as they block out pretty much all voices where ANC doesn’t.
The Poly with a leather case is sure a very elegant solution. However, it is a bit fussy with wifi (sometimes have to wait 5 minutes or more) and the batteries are always empty. Moreover, you can’t use your own software as you can with the pi (poly has no samba e.g., i.e. you have to take out the sd card to load files).
I would recommend some velcro straps and a power bank to feed both the pi and the mojo.
Question is where to put the bear.
I am expecting to be wearing a neck collar following neck surgery soon .(Too many hours squinting at computer screens over the years)
I expect conventional over ears will not work with the collar so I invested in some Sony WF-1000XM4 IEM’s
So far the sound is quite remarkable. I normally use Sennheiser HD800 and my over ear Sony 1000 XM4’s on Bluetooth. To be honest I was expecting the IEM’s to be a bit iffy but not the case.
Getting the ear buds seated is a bit fiddly at first (early impression) but the overall effect is really quite good, it will certainly be good enough for the 6 weeks in dock !!
The next delivery is a 1 Tb SD card for my phone so I can load up more that I have currently , I can sit and be “bored” with the Ring Cycle for hours on end …
This is taking downsizing a bit extreme I suspect 
The XM4’s are absolutely great. Very underrated.
I’ve pulled out my HiFiMan Sundara closed backs and AQ Cobalt. A simple setup and much much better than AirPod Pros.
In the below photo is my MOCK core (Linux Roon Server) running on a MeLe 3Q with a custom heat sink (looks are undecided), Topping E30, Sabaj valve amp with HiFiMan Sundara closed back cans.
The core is running on Wi-Fi (very stable and has been in use on a multi speaker group without issue).
Lol, some furry headphones you got there.
It was more the threads title I was posting in jest of.
The four legged acoustical friend was collateral.
Headphones are known as cans so there is a tenuous link there
These “humble” HE-400i are really fresh and vital, with these team mates!
Senny’s HD820’s are THE BEST closed-back headphones I have ever heard. I was sat-on-the-fence about these for a while, mostly because of the mixed reviews.
But MY-OH-MY, with the FiiO M17 I have never heard anything like it 
Oh man, I am looking for a pair of closed-backs, and I’m very partial to the 800S open-backs. I wasn’t going to get a pair so similar, but you’re close to changing my mind.
I presume you’re using a balanced cable? Again, there’s something about the HD800S and the balanced output on the M11 that I can’t get enough of ATM. For the record, I’m generally sceptical about balanced headphone cables.
I absolutely love me adore my HD800’s (the original, and not the HD800S). They’re impeccable for classical music especially, and are a thrilling listen.
The only problem with them is being open-backed, they leak like hell (as you know) and my other-half complains, and the bass/sub-bass is less than ample.
I’ve gone through so many pairs of closed-backs, looking for the right pair: Sony MDR-Z7, MDR-Z1R, Beyerdynamic T5p, Beyerdynamic DT1770 PRO etc. The closest I’ve got to my ideal pair is the Beyerdynamic T5’s, which are actually very, very good.
But these HD820’s are something else entirely. They just eclipse ever other pair of CB’s I’ve ever heard.
If you like the HD800’s/HD800S and you’re looking for a CB set, I would highly recommend an audition.
