theres no way to see what crossover they are.il give dad the benefit of the doubt :-P

i think they are efficient,theyre only rated 50watt rms

i thought an isobarik would be ok to keep enclosure size minimal(ie realistic size)
dad said they go well in 6cubes\
so i thought 3cubes isobarik 47hz tuned for some 'punchy' midbass kick :-)

lightweight cone,it wobbles around several mm when my other sub is powering away on 10watt (jbl)