A far as I know, "させる" means make something happened.
彼を満足させるのは難しい = It is hard to make him satisfy. (Correct me if I am wrong).
But when I was reading a light novel, I saw the following sentence and I don't know what させる means here.
Does it mean that the song is made similar to the song of メルル?
If it is the case? Why can't it just say
俺の知っている中じゃメルルの歌に似て? Which is easier to understand.