Having heard many BG/Radian 10 drivers, I think it’s important to give my 2 cents, and that is that as these drivers start playing lower, distortion goes up, particularly if only one is used. I would contend that, as Radian says a 500-5k range would provide max output, lowest distortion but ultimately that lower region needs to be augmented with an 8-10 inch driver before hitting the subs. This optimization can clearly be seen in Igor’s ( the gentleman who designed both BG/Radian 10’s) speaker as he uses a Radian3/10 to a 10 inch OB, followed by a 12 inch sealed where each driver is working its correct space. Even if you look at Danny’s charts above you can clearly see the 10 starts to fall off the table ~350, and I would also contend that there is a lot of mid-bass slam between 150-350, and I personally think that although the OB subs can play up too 200, that’s probably not optimal for a 12 inch driver. To go one step further, I completely understand that a lot of folks here like to use passive X-overs, and that adding another driver into the mix can get quite expensive so I completely get why folks like the simplicity of a small, 2 driver solution.
Sorry for the early morning ramble, at the end of the day it’s the sound that matters, and if you like the sound, great!!
Don