Cord to use mono or stereo?

I have been using the LH and RH out with a splitter cord however, im told i only need to plug into the LH jack instead and still get the same effects as i dont use 2 cords (one to each speaker). My question is which cord should i use in the LH jack? A mono or a stereo to my mixer?

The answer is in this post: Question about stereo: - #3 by hawbringer

Thanks. Perfect