Use in situations where control is involved, like turning down music or decreasing effort. Can you dial down the TV? It's too loud.
Pro Tip 2/3
Metaphorically Speaking
Often used metaphorically to suggest becoming less aggressive or assertive in behavior or speech. You should dial down your arguments when talking to the boss.
Pro Tip 3/3
Tactical Softening
Strategically used to prevent escalation of a situation or to smooth conversations. He dialed down his tone to avoid upsetting her further.