Audio physic step speaker parts


My audio physic step speakers blew the midrange woofer
im trying to find a replacement midrange for them , thought maybe someone has an idea where to find themĀ 
they are SEAS h637 4 ohm 4inch woofers made in 1997
i tried contacting seas distributer in the USA , but couldn't find a perfect match
any info / ideas would be much appreciated

j4gold