Jon, your experience coincides with mine and many, many more in my experience. The fact that the amp doesn't double into 4 ohms says that it is out of power as current demand increases. Thiel speakers have low impedance for high current appetite , especially in the bass. So, doubling your available current in the bass is germane. Your blown midrange was almost certainly caused by distortion which heated the midrange voice coil beyond its limits.
As an aside, the only driver failures I have seen have been burned voice coils, caused by overheating, caused by distortion. In all the years of heavy-duty, overnight, stress and show conditions, I am not aware of ever "blowing" a Thiel driver. We had big amps with high current delivery power supplies.
As an aside, the only driver failures I have seen have been burned voice coils, caused by overheating, caused by distortion. In all the years of heavy-duty, overnight, stress and show conditions, I am not aware of ever "blowing" a Thiel driver. We had big amps with high current delivery power supplies.