another option that may or may not be possible for you is to use an external mixer (if you have one) which usually have rca inputs and use the outputs on the mixer to your speakers. This is just if you don't want to buy the above cables and you have access to a mixer.
Yet another option would be to use the rca inputs on your speakers (my event speakers have them, I don't know if yours do).
By the way, it would help to know if your speakers are active or passive. You might need to use option 2 with a power amp if they are passive.