about 1975 or so
when dad lived in Auckland (the biggest city of nz) back when he was single he had them..and only recently built them haha
i think they have 2nd order filters -he hopes he reversed the phase on the tweet he cant reemember hahai also have 2x12" philips 8ohm with whizzers,seem to be Fs=47hz Qts=0.4 the cones all floppy when u push it :P
i think i might isobarik them put them in the car haha
dont know vas,il just try a box :-)
cheers!