> Anyway I tried the same test with my hd58x and Arias and i've got the same result as the Diokos, no rattling sound or nothing else I think.

Thanks.

It's mine and daughter's at this point, so makes me wonder.

Could you answer this specific question please: do you hear absolutely nothing "else" at the end of the every third low frequency "beep", when it goes from beeps of one frequency, to another?