"It seems like lowering the volume of the signal should be a simple matter!" Aikhwarizmi
It is.
Attenuators are about as simple electrically as you can get.
They are just a few resistors, or a single variable resistor. I can't see how anyone could charge hundreds of dollars for one. There are precision attenuators used in radio work, but they are an altogether different animal.
I have built some into cables. If anyone here in the states wants one, let me know, and it's yours.
Rob.