noise from my Logitech Speaker

[metachi]

please listen

https://soundcloud.com/reddemonic%2Fnoise

My speaker model is Logitech Z523 2.1

I dont know if this noise is normal or do i need to get a replacement?
When i have nothing playing, it makes this noise and something it gets on my nerve. The noise isn't actually that loud but hearable.

Please help me out

Thanks
Alan