I present my attempt at an easy to print headband for my Borealis inspired headphones (TH4A/B).

The DIY Borealis earcups can be found here: https://www.thingiverse.com/thing:5103331

These were designed to use few non-3D printed parts and for those parts to be easily sourced from ebay, aliexpress, etc.

There are two configurations these headphones can be built with, depending on whether you plan to use a bridge cable between the two ear cups or not. The 07 version of the forks don't have mounting holes for the cable clips, while 06 does, so only the 06 version is suitable for use with the bridge cable arrangement.

Parts Required (other than printed parts):

4x Aluminium M3 x 60mm round standoffs, 5mm diameter (ebay, various other lengths and colours are available),

1x Beyerdynamic DT770/990 headpad (copies can be found cheaply on ebay).
Alternatively a piece of adhesive backed foam can be stuck on the inside of the headband to provide suitable padding. I used 5mm x 25mm foam, approx 210mm long. Please note that the Beyerdynamic headpad is needed to hold a bridge cable in place and is generally a lot more comfortable.

Fixings:
8x M3 x 10mm Countersunk Hex A2 screws (used to screw into both ends of the ali standoffs),

4x m4 x 6mm Grub/Set screw nylon or nylon tipped (used to add resistance to the Ali standoffs in the headband).

All holes should be drilled and tapped for the correct thread.

Tools Needed:
Small hand drill,
2.5mm drill bit (tapping drill size for m3 x 0.5 threaded holes),
3mm drill bit (for all non threaded holes for the m3 screws),
3.3mm drill bit (tapping drill size for m4 x 0.7 threaded hole),
5/5.1mm drill bit (widening the headband holes for the ali standoffs),
5.3mm drill bit (for the fork pin holes on the forks),
Small countersink bit (for all countersunk holes to clean them up and deepen if required),
M3 x 0.5 tap (for almost all holes)
M4 x 0.7 tap (for the 4 side holes in the headband)

Remixes are encouraged. Please share any ideas you may have on this project with the community; by using the REMIX button on your upload.

These CAD files were created with Solidworks.
There are both Solidworks and .STEP files included, along with the .STL files, to aid in making modifications.

I hope you find my work of interest.