I'm an AR fan. I've said it here before. It's the first mod I do and it's very rare that I don't do it. So when it came to a TC sub, it needed an AR cyclops (I realize AR is not correct unless it's a service Xtal)
BigCrown made some custom gen spec crystals with AR on three surfaces of the cyclops, on the main glass under the cyclops and on both sides of the cyclops. The result is an incredible black hole effect.
I bought the crystal long before ever owning a TC sub. As luck would have it, I ended up getting the TC sub with a BC Xtal already installed. To this end, it is the only Sub Xtal I've ever know. However being an AR snob, the bluish purple tint of the AR on the BC Xtal always bothered me. I finally pulled the trigger and bought a gen Rolex Xtal with AR off a member here.
The first thing you notice is the AR on the cyclops of the gen is much less blue then on the BC Xtal. This is difficult to show in photos but you can see it here if you look closely. Gen on the right.
What's way more noticeable is the top beveled edge. The BC beveled edge is substantial and has crisp edges while the gen has much less of a beveled edge and the traditions seem to be rounded rather than crisp and squared off. Here are pics through a 10x loop BC then gen.
I'll post some pics of it installed. Waiting for my Rodico to come in before doing the mod.