Love Danny's videos.
I've read/seen so many articles and videos over the years where the author/commentator was clearly just speaking some marketing drivel that didn't make any sense. Danny's videos are a breath of fresh air. He does a great job of presenting the science and engineering behind various aspects of loudspeaker design and the trade-offs where they exist.
Watching these videos convinced me to build some of his designs. I've been building the NX-Oticas for the past several weeks. Open baffle subs come next.