The following is what type of sentence unless it's quiet I won't be able to think so please turn down that music?

The sentence "Unless it's quiet, I won't be able to think, so please turn down that music" is a complex sentence. It contains an independent clause ("I won't be able to think") and a dependent clause ("Unless it's quiet"), along with an additional request ("so please turn down that music"). The use of "unless" introduces the condition that affects the main idea.