Editor’s Note: Here’s an interesting thread from the PSW Live Audio Board (LAB) forums. It’s lightly edited for grammar and formatting. Enjoy.
Posted by Dave
I have been considering a couple single 18-inch flown subs at the top of my array, specifically for a couple amphitheater style venues where the top of the venue has a significant reduction in low end due to the subs being at ground level.
Does anyone have experience with the flown subs in general?
Reply by Tim
Depending of the space between the flown subs and ground stacked subs you can create vertical power alley and, using delay, steer the sub lobe up/down. You will need roughly the same output levels (within 3 dB or so) in order to do this effectively but just putting a sub at the top of the array will ‘raise’ the sub coverage a bit.
Experiment with it, Dave, and let us know what you find…
Reply by Ivan
The biggest advantage to flying the subs is you get more even coverage from front to back. The distance to the rear does not change, so that level will stay the same. But the distance to the front changes a good bit (in terms of dB), so it is quieter than when they are on the ground
Reply by Luke
The down sides to flown subs is floor bounce and a little loss of impact from the subs due to time of flight. The advantages have been pretty well explained. More even coverage and easier alignment to the mains are the two big advantages. I am not a fan of flown subs unless they are on a separate hang behind, or right next to the mains. If the subs are part of the same hang as the mains, it just doesn’t have the same impact and effect to me.
Reply by Al
Don’t use it as a sub, but more of a low end extension to your array.
Reply by Tim
If you’re used to subs on the ground and the “up close and personal” experience for the front rows (some may like, some may not), then yes there is a perceptual difference. To deliver the same SPL in whole space loading requires more acoustic output from the subwoofer pass band so that’s more weight in the air and in the truck but I think it’s a deployment worthy of consideration (especially with some subs on the ground, too).
Time of flight? When hung as part of (in sufficient numbers), adjacent to, or behind the main vertical array the subs have nearly the same time of flight – give or take a few, alignable ms – as the mains, to most every seat. With subs exclusively on the ground the coincidence of arrival will be different at most every seat. This is one of the reasons Ivan likes to fly subs up with the mains whenever possible.
A couple of subs in full space (at the top of the array) will not ‘keep up’ with an equal or greater number of subs on the ground. Basic physics.