It seems to me that you are not familiar with the bass management systems and the filters employed in AVR/AVP devices.Here you have a loudspeaker with what looks like a 18dB/oct high-pass filter which looks well defined and right where it should be.
Adding an additional 1st order electrical filter and maybe a bit of EQ is all that is needed to form a 4th order LR crossover with a sub for example.
This would be trivial to do, even without measurements if the characteristics of the high pass is known and well chosen.