In a karaoke room?
mics - speakers - TVs - CD players
In a kitchen?
oven - microwave - lights - timers - a fridge
Maths class?
a calculator - TV LEDs - projectors - computers
At the beach?
mp3 players - speakers - mini fridges - earbuds
In winter?
coffee maker / central heating / heater
At a McDonald's?
microphones - speakers - vending machines - screens
In a supermarket?
fridges - cash registers - smart TVs - phones - speakers - washing machines