Tofty Headphones 4: Aurorus Borealis Inspired

I present my remix of the Aurorus Audio Borealis/Australis inspired DIY Headphones. As of the 24th of January 2022 all files have been updated and there are two versions of this design: TH4A is the original version and is the red and blue model in the above photos, TH4B has a redesigned headband and is the silver and black model in the photos. The major change in my design is the addition of a second set of connectors at the rear of the earcups, which allow the use of a removeable bridge cable. This means that the headphones can be used with either a split cable, without using a bridge cable, or with a single sided cable that can be plugged into either side, with the bridge cable installed. However it can also allow the headphones to be converted to wireless, relatively neatly by using a Bluetooth Receiver and a 3.5mm TRS jack wired into the bridging cable. There are printed Conn Mounts designed to take three different connector types (see photo above): Mini XLR male external screw in connector, 3.5mm TRS Jack female external screw in connector, 3.5mm TRS Jack female internally installed with external securing nut. There are also versions of each of these Conn Mount parts that are only single sided and don't take a second connector; for builds that do not plan to use the bridge cable. This means there are six different Conn Mount options. The cable clips for the bridge cable are designed to take cables with a 4mm diameter. If the cable used is narrower then some strategically placed head shrink sleeving can be used to make up the difference. There are different versions of the Forks and Band Clamp parts; some that are designed for the bridge cable and others that are not. The headphones can be built as either open-back or closed-back, using either the Outer Ring or Outer Cup parts respectively. It is advised to check either the .STEP or Solidworks files for both the TH4A and TH4B versions of the headphones, to help identify all the differen