Horizontal vs vertical stack of 4 horns

Conanski wrote: There won't be any difference that is why you're not finding much chatter on this, the wavelengths in question are much larger that the speaker stack so acoustically it doesn't matter, use whatever layout you like the looks of better.

Not based on my experience. Bass horns are directional within their pass band. The whole idea of stacking horns vertically is to minimize spills from the sides. I've done too many events outdoors with bass horns decades ago where, the orientation of the box plays a factor on the dispersion. This may not be noticeable indoors with so many boundaries bouncy the sound around. However, outdoors is a whole different story.

Best Regards,

As people have said, especially indoors, a small number (say less than 8) of 18" bins won't show much change in directionality or dispersion whichever way you stack them. Once you have enough bins for one dimension of your stack (the width or the height) to become comparable to the length of sound waves in their passband, you would start to see directional effects. It is just the same as the way a 12" speaker starts to have narrowing dispersion at the frequency where the wavelength is about 12 inches.

You might perceive, especially outdoors or in a very big space, the relatively small area around a small bass stack where there *are* differences in SPL - obviously if you stand behind it vs in front of it, you're probably going to feel more pressure in front, and your SPL meter would read higher. However, at a range of more than say 10 metres, this effect disappears and the sound field becomes pretty much even 360 degrees (again outdoors, away from boundaries.)