Any issues with standing waves in the concrete form? They look really amazing.
I sold high-end audio for years at a boutique shop... McIntosh, M&K, B&W, Linn, Meridian etc... I think a lot of it's nonsense price-tag wise except for stuff that's bench-made like McIntosh and lasts 50+ years. I grew up with Mc gear, and it still works to this day and sounds great. The problem I have with high-end audio is that people are always (not you, just folks in general) seem to be trying to re-invent the wheel and then charge *huge* money for speakers and gear that isn't any better than product costing 1/5th of it's price.
Case in point in the watch world the new Grubel Forsey $300k tourbillon with a bump on the back of it... an ugly watch and probably uncomfortable. But it's haute-horologie and despite being utter nonsense they're all spoken for. Same thing happens in high-end audio with $20,000 speaker cables and other bullsh*t.