The artical Jerry posted explains it very well. If using regular speakers , stands are necessary. No one hated stands more than me. A pain to move, set up, get the speaker on/off, big footprint on small stages, danger of tripping.
I solved the problem with my linear PA the Eon Ones. I have a pair.One of the best investments I ever made in equipment. There are many others doing this type of PA now including Mackie who just jumped in. With 12", 10", 8" subs depending on how much power you want. Check them out. Not only do they sound better, give better dispersion, and to me much more clarity, but they pack up into themselves so are easy to move.