Okay, I'll be honest with you here. Sirens aren't mermaids. Not in the slightest. You know what they are? Bird woman. Which... Is kinda like Harpys, so I do understand why people just go ahead and make them into mermaids. But they still function somewhat normally to the rest of the depictions.
So, you see, Sirens main known abilites is the ability to lure in people with a song. We see in the the Odyssey, the one with Homer. Now, lure wise, there is no way to be uneffected by this song. Some people have clamied that asexial people would be completely fine, which is shit. Quite frankly, as the siren song has nothing to do with sex or allure in that manner. They're more like extremely good music.
In other ways, it's likely that the siren's song would be just some badass music. So, depending on who you ask, it could be some lovely classical music, blues, R&B, Metal or pop. I like to think it's just Metal. But our boy, Homer did try to listen to the siren song, tied up to the boats mast if for safties sake, and apperently said the music was beautiful and since beauty is subjective it could leave numerous different ideas on what the siren song is supposed to be.
Well, since there's no way to know what a sirens song would sound like without getting almost completely stuck into the trap. Which could be interesting to think about as a sort of cognitohazard. If that makes sense, like seeing 096 or SPC: Shy Guy or Roko's Basilisk. I wondere that if playing a recording of a sirens song would have the same effect as the siren singing it out.