maximizing my sound

Not until you get about 20 feet out from the stage will you notice anything, even then the difference is marginal. Typically one would put the 4x10 on top of the 15.

 

I would think that the difference would be more noticeable on stage since stacking the cabs puts one significantly closer to your ears than the other. This difference should dissipate as you increase the distance from the cabs as they begin to behave more like a point source.

I would try it both ways and see which one you like better. If there is no discernable difference then stack the lightest cab on top

 

+1.

 

Could someone please explain this to me?

 

I tend to disagree...if you are stading in front of a 115 or a 410 they will sound different...so which ever cabinet is on top will sound different to you. Also 20 feet out the difference can be a big one. With the 15 on the bottom it can become more muddy than the 410 depending on the 410.

 

Still waiting . . .

 

. . .

 

the sound variation will change with distance. at 4-10 ft it may not be noticable at 10-20 ft it may be noticeable at 20-40 ft not as much. there is a sweet spot where the voice of certain speaker shine and that also depends a great deal on the way the whole rig is powered and wether it is full range or crossover or bi-amped. the number of drivers will efect the mix as well.

Hard to say but try experimenting and see what you like and check it at multiple distances.