Cable for my Rythmik F12SE Sub

To the Rythmik's high-level input/binding posts?

To the line level input @bdp24 thanks

Ah, okay then the Kimber Hero, great for bass/low frequencies. I use it with my F15HP's.

Thanks @bdp24z I see they go for around 300$ am I right ?

Depends on the length of course, but I got mine used. I'm not sure what the Hero goes for new. Kimber offers three different RCA jacks affecting the Hero's price, the difference being more in higher frequencies. For bass the cheapest plug----the Ultraplate, is fine. There is a retailer in Los Angeles selling them regularly at a discounted price on the big auction site.