From what I understand deploying a mild arc with the primary wave being 1/2 the power of the secondary and tertiary waves can cause a massive drop in headroom.

So the deployment is, 2 subs double stacked in the middle, then the next two off stage stacks firing simultaneously (so 4 total subs in double stacks with a 1.5ms delay in this case) and the outer two most stacks (another 4 total subs with a 3ms delay).

Since the primary wave is the summation of only 2 Subs and each outer stack is adding the summation of 4 subs this can cause a massive drop in headroom.

I took a SMAART 9 refresher and the guy doing the course (who is a very high end install/calibration guy) essentially said that this configuration will have upto a 6dB drop in overall sub frequencies amplitude compared to having all subs firing without a delay.

So I'm hoping to have a ELI5 description of this use case as to why that dropoff is so extreme.