Reply to Macbook humming sound?

Hiya guys have a slight problem with my Macbook. When i plug my Hercules Rmx controller into my Macbook it makes an awful humming noise. Im pretty sure its coming from the RCA - AUX cable which i plug into the back of my controller and then into my speakers.

But when i connect it all up to my Windows laptop every things works fine and there is no humming at all, only when connected to my Macbook?

Has anyone exsperiencend this and have any solutions for it? Many thanks.