General information on interconnects

When it comes to cables, I really don't have a clue. I don't understand the difference between single rca interconnects and the regular ones that have the right and left ends. I'll give a quick example: when I am going from my phono preamp to my active speakers, I am using the regular cheap monster rca cables that have the right and left ends on them and then when connecting to the actual speakers, I am connecting the right rca to my right speaker and then the left to the other speaker. This setup seems to work, but I wanted some more information on the subject. Thanks.