音乐会 usually refers to play musical instruments. 演唱会 usually refers to singers' live show.

音乐(music)会 and 演唱(singing)会 are different just as you can read in Chinese.

前面两位的答案我认为非常准确！涨知识了。补充一点，“演唱会”这个词似乎来自于港台。

Hello again, dear Noah, 音乐会 usually used in some classic music live. The pianists and violinists ,or some have that kind of occupations will appear on the spot to perform the symphony. However, 演唱会，dividing this phrase into three single parts to explain would be much easier to understand.演as a verb means to perform, 唱still is a verb which means to sing or chant, and 会 means meeting together the fans and the singers or bands, 演唱会 this word appeared later than the former, so it is always used to describe the spot of pop , rock, jazz and the like. LOVE U Plus