From Longman Dictionary of Contemporary Englishraise/lower the tone (of something)raise/lower the tone (of something)RIGHT/PROPERto make a place or event more or less socially acceptable, attractive etc That horrible building lowers the whole tone of the neighborhood. Trust you to lower the tone of the conversation (=by making rude remarks etc). → tone
Examples from the Corpus
raise/lower the tone (of something)• Far from lowering the tone, the changes are set to improve it. 