Nothing to Hear Here

Mater connected to the Internet today when I recommended to her a brief segment of film I thought she ought to watch online.
"I'll watch it at the same time," I said over the telephone, "so that we can follow together."
I suggested that Mater indicate to me when she was about to press the start button so that we could begin and so that we could be synchronised.
Mater's usual formula, when I make such requests, is to press the start button and only then proceed to fumble about with a pair of enormous headphones, and then attempt to connect them to the computer; by the time the wires are untangled and the headphones are in position over her ears, and Mater is able to sit still and listen, the video has drawn to its conclusion. We either begin again or I slide off to make a cup of very strong and very sweet tea.
This time, Mater was unruffled and ready- and oh, so proud of her foresight. She intended to surprise me with uncharacteristic composure.
"I've already got the headphones on," she boomed over the telephone. "I'm ready to play."
I offered words which she could not establish the nature of- the headphones, of course, were enveloping her ears and muffling my comments.
"Pardon?" Mater prised the headphones up slightly in order to hear me better.
"You don't need headphones," I repeated, as gently as I could to soften the blow that must fall. "I'm sorry. It's a silent piece of film. There's no sound."
And for one long and particularly deflated moment, there was no sound from Mater.