I hate test tones, at least with music you get some breaks and frequency changes. Your crazy as hell going in there on a test tone. Last time I was standing in a open door during that shit and I couldn't breathe lol. Thanks for the video man and stay safe.
When you hear an echo watch out it's loud. That means your box📦 is built like a rock my box has that same echo in my box and yes my box is a smaller 2 18 ported no wall now this build is way louder!