[Face]

First, we're almost deaf to distortion at those frequencies. For example: http://www.phys.unsw.edu.au/jw/graphics/ISO226.png

Second, since their drivers are custom and their enclosures are designed by them, there's other ways to tune out low bass without adding a high pass filter.

One way would be to improve their woofer's motor by increasing magnet strength, adding more copper, etc...and distortion would be decreased too. For example, look at this beast of a woofer: http://www.scan-speak.dk/datasheet/r...Ton_2013-2.pdf

But a low pass consisting of a cored inductor and electrolytic caps would be much cheaper.