Maybe he just simply wants to know. I wish I would know the figure, so I can help in the way the op wants A person who gave me advice on another forum about my IB setup requested the info. It had to do with trying to avoid bottoming the drivers as I've tapped the bottom a couple times and would prefer not doing that anymore . I've seen it speculated to be around 40mm, but I would expect a bit less than that. 35-37mm seems about right to me, but it would be nice to know for sure. It's kind of hard to replace those drivers.
