Bigscreen Beyond - Apple Vision Pro Strap Adapter w/ MMI Modular DAC & Valve Index BMR Adapters

Adapter that allows the Bigscreen Beyond or any other HMD with Beyond-style headstrap nubs to use an Apple Vision Pro-style strap and the Valve Index BMR Speakers via the amazing MMI Modular adapters and DAC module. No soldering required!

Requirements

• Valve Index BMR Speakers. I bought mine from https://tundra-labs.com/products/index-speaker-new. Left and Right sides are distinct, you'll want one of each.
• MMI Modular designed and sells the DAC and BMR adapter PCBs used in this build: https://www.mmimodular.com/projects/electronics/hummingbird/
  • Specifically, this is designed for these two items from the MMI Modular Shop. 
    • Valve Index BMR Adapters - choose the “hummingbird kit” in the dropdown for the variant with 3.5mm jacks: https://mmimodular.myshopify.com/products/valve-index-bmr-adapters?variant=45569270448364https://mmimodular.myshopify.com/products/valve-index-bmr-adapters?variant=45569270448364
    • USB DAC with the female USB-C port and picoblade connector: https://mmimodular.myshopify.com/products/usb-dachttps://mmimodular.myshopify.com/products/usb-dac 
• Uses just two M2x6 cap-head screws (you can find these in assortments on Amazon)
• You still need the picoblade connector described on MMI Modular's page above. I used this off-the-shelf available cable that works well and is available at many retailers https://shop.aquacomputer.de/Monitoring-and-Controlling/RGBpx/RGBpx-cable-length-4-cm::3762.html?language=en
• Roughly 1' / 30cm 3.5mm male/male speaker cable, Ideally one with 90 degree angles at both ends
• USB-C Cable that makes sense for your HMD. I used a 10cm cable with 90 degree angles on both ends

Printing

• I used Polymaker PLA with limited tree supports for the arms, and no supports at all for the covers
• See photos for my print configurations that worked for my Bambulabs X1C

Assembly

• For the right side, connect the DAC and BMR Adapter PCB with the picoblade connector. you'll need to wind the wire a bit to have it nestle into the shell
• On the side opposite of the single screw hole, the cover should hook into a recess to fix it in place.
  • Place PCBs into the ARM modules
  • Hook the cover under the recess on the short side furthest from the single screw hole in the arm
  • (right side) gently guide the coiled cable to sit in the recess between the PCBs
  • Finish closing the cover onto the arm
  • Place the M2x6 screw in the hole pointing out, and thread it into the Valve Index BMR speaker module (ensure you're using the matching side for the arm you're assembling

Other Headsets

If you want to use this with a MeganeX Superlight 8K, I personally use Akari's Modular Facial Interface: https://akaricrashed.com/portfolio/akaris-meganex-modular-facial-interface/ with the Bigscreen Beyond adapters that I made here: https://www.printables.com/model/1339070-meganex-modular-facial-interface-bigscreen-beyond

Update 2025-10-22: Added more detail and direct links to the required components from MMI Modular