This is a Remix of Balazar’s Open Alpha with bass ports. This version contains a strengthened and modified output jack that allows for the use of 2.5 and 3.5mm connectors instead of the standard Hirose connector. The Hirose connectors can be hard to source and the standard the 2.5mm connector an easy to find and more versatile substitute.
The connector wall is thickened by 0.2mm. The output hole diameter is 5.9mm and perfectly fits the following Lumberg 3.5mm connector
Massive thanks to MrSpeakers for releasing the original source files. For the best sound and to support the project purchase the Alpha pads from his online store.
The rest of the files and project discussion is here at headfi
Downloadable on thingiverse
Print The Cups in ABS. 3.5mm connector gets installed
Smooth the cups in an acetone bath
Prime with a filler primer and coat in automotive paint. I used hot rod red from Duplicolor.
Add the driver to the baffle, cover the rear of the cup with silverstone dampener. Sandwich wool in between to control treble.
Close the cups with four 10mm M2 screws each.
Use contact adhesive to cover the rubber headband in leather.
Temporarily cable tie the headband till it dries
Enjoy your new headphones. It will require significant tweaking of wool and dampening till the sound right.