Except that is his square wave reference, for a start. If you don't drive really loud, it still performs admirably with low bass. And as for its impedance, while it does have an unusual swing for a single driver design, it still has a relatively high output impedance. Compared to an "ideal" load, sticking 30ohms worth of resistor wouldn't even change the FR at ~100hz by .5db.
12/9/12 at 10:04pm