Superlux HD681 detachable cable mod

This is a modification of 2 lids covering Superlux HD681 headphones to allow for a detachable cable mod. Modified version of the main (bigger) lid misses the fancy "beams" in holes due to them being difficult to print. If you still want version with beams let me know, though I think I'm gonna add it either way later. Modified version of the secondary lid features a housing for a 3.5 mm connector. I must say that I used another model to get measurements and recreate it, though I still did the all job myself with the sketches and all (because for some reason I couldn't modify the step file in FreeCAD lmao). Anyway props to that dude and his model, genuinely, saved me 20 mins of grabbing the calipers and going through the trouble of measuring everything with it.