I linked some of my videos from my own stalled version of this project in your similar post on Facebook. Hope you had a chance to view those, as they represent my best info on the likely headphones used, a good modern stethoscope choice, and the 3D printed parts by Ryan.
As for this specific question:
goodale.jason wrote: ↑April 4th, 2021, 12:35 pm does the extra tube connect to the computer?
In this photo where he's examining the table in the Library, the extra line on the stethoscope leads visibly into Egon's other pocket, the opposite direction from his PC-4 and interface.
I really don't think they're connected. Though, I still have no clue what the line leads to in the other pocket.
Some of the alternate takes of the 'Ready to Believe You' commercial likewise show the line going into the opposite pocket from the PC-4.
The cord that goes from the PC-4 interface straight down into a pocket on Harold's left is just the actual cord that comes with the device.
More info on the PC-4 and interface can be found here:https://www.gbfans.com/equipment/other/ ... alculator/