deaden (a sound or noise), especially by wrapping
make less strong or intense; soften;
"Tone down that aggressive letter"
"The author finally tamed some of his potentially offensive statements"
- He toned down clashing colours with brown tints.
- His tone became soft and conspiratorial.
- The newspaper toned down its attack.
- She tried to tone down his anger.
- tone down （使）柔和