Howdy!

Bruits de fond translates into English as background noise.
To make it work four pairs of headphones is what it employs.
When I listened to them on the benches I discovered that it annoys.

Mumble mumble, gurgle gurgle, tweet tweet
Natural background noise can be very sweet.
When computer generated I want to hit delete.

The headphones had wires,
The benches were hard.
The MACM needs iPod suppliers
Sitting in one place for 25 minutes is not avant guard.