lower the tone (of something)RUDE/IMPOLITEto make something not as nice as it was 败坏（某事物的）格调 They thought an influx of students would lower the tone of the neighborhood. 他们认为大量学生住进来会破坏这街区的格调。
Trust you to lower the tone of the conversation (=include rude jokes etc in what you say)! 你肯定会降低谈话的格调！
lower the tone (of something)• Far from lowering the tone, the changes are set to improve it.
→ lower the tone (of something) at lower2(3)