I'm building a new home now, and would like to put speakers in on the first floor. I just went to the speaker shop and heard some JBL in-ceiling speakers, which sounded outstanding. These speakers come as single-channel pairs, so I have to install them as a right and a left.

Is there a general guideline for how far apart to space these speakers? I was thinking about putting them about 15 feet apart, but wasn't sure if that would be too much or too little.

Does anybody have any advice on installing in-ceiling speakers for music through a whole floor?