So it goes...

 

MY BRAIN HURTS

 

In theory, yes, in practice it's a bit more.

 

That's why my behringer interface headphone output signal is normalled at 20,000 volts.

 

No, but load resistance is going down, so the output stage has to deliver more current. To calculate the drop in output voltage you need to know the output impedance and the load resistance of all connected loads together. But to assume a splitter halves the amplitude is wrong.

Let's say you connect 16 line level inputs with 2 kOhms input impedance each in parallel to a headphone output, that results in 125 Ohms which should be fine for a headphone amp. So even if it looks silly, it actually works if all the adapters have good contact.

Of course, it won't work if you connect 16 headphones with 80 Ohms each. That would result in 5 Ohms and you would need a speaker amp for that.

 

I didn't know Phil Collins had a sex tape.