Headphones - wireless Bluetooth (BT) or wired

Over-ear Bluetooth headphones are quite expensive so why not make them yourselves?
I've browsed thingiverse and found nothing which I liked. However the Duli v2 had some nice features I could use (thing:674179).
I've started out with some testing and finally had the right cups for the sound.
The current version works quite nicely for me.

I placed this as a 'work in progress' though at the moment it's quite finished.

What do you need:
1: PETG filament (I use eSun)
2: A bluetooth AUX Audio Adapter - I Used: https://www.banggood.com/BlitzWolf-Bluetooth-V4_1-Car-Handsfree-Music-Receiver-3_5mm-AUX-Audio-Adapter-p-1051628.html?cur_warehouse=CN (about €15,-)
3: 3.5mm stereo male jack plug - https://www.banggood.com/3_5mm-3-Pole-Golden-Male-Repair-Headphones-Audio-Jack-Plug-Connector-p-940438.html?rmmds=search&cur_warehouse=CN
4: 3.5mm stereo female jack chassis mount, it must have a nut for fastening it to the speaker-cup) - something like: https://www.banggood.com/5pcs-PCB-Panel-Mount-3_5mm-Female-Earphone-Jack-Socket-Connector-p-1038048.html?rmmds=search&cur_warehouse=CN
5: single string stereo wire, 50 cm in length and a 1.9mm in diameter (smaller is also ok.)
6: 2 Speaker drivers 40mm - I used: https://www.banggood.com/30MW-Replacement-Earphone-Speaker-Unit-for-Bose-QC25-Headphone-p-1232965.html?cur_warehouse=CN (€3.26 per pair) In my experience 40mm drivers are the best size, smaller ones wil give a flatter sound. (but if you really want to use smaller ones then just resize the inner diameter of the front baffle inserts.)
7: velvet ear pads: https://www.banggood.com/Velour-Velvet-Replacement-Ear-Pads-Cushion-For-AKG-K240-Studio-K240MKII-K270-K271-K271S-K272-p-1066665.html?cur_warehouse=CN (€2.74)
or
PU leather (better bass and privacy) ear pads : https://nl.aliexpress.com/item/Replacement-Ear-Cup-Pads-Earpads-Cushion-For-AKG-K240-K241-K270-K271-K272-K280-K290-K340/1235381384.html (€10.64)
8: When using the headphones wired you'll need 1.5 mtr cable with at least one 3.5 mm stereo male jack and whatever you need on the other side. (I had an old broken USB headphones lying around, that works also making the headphones very versatile).
9: Rubber headband padding
10: A soldering iron and some solder.
11: All the printed parts, printing the baffle and baffle insert twice.