I have a problem with my Yamaha NS 45 ( NS-45E ), The hightone speaker is broken (on the top of the woodbox); it's silent like a stone. Would you provide me the parameters of this speaker (on the magnet the fallowing symbols could be found: YAMAHA XW307A0; I hope that 0 is zero not 'o' letter)? Or maybe you have any suggestion what speakers should I insert instead of the broken one?