Woofer track replacement for Bluedio R+ Legend

Hello,

I was very satisfied with my Bluedio R+ Legend headphones but the woofer track in the right pad is not working anymore. I've open the headphones, it's a 50mm diameter one.

I would need a spare one but I don't know what impedance and wattage should I use. I found that the V Victory model uses a 42 ohms woofer (source: Amazon - "Impedance: 42Ω (50mm)*2; 32Ω (30mm)*2; 32Ω (20mm)*8"). The thing is that the Victory model has 12 drivers despite 8 drivers that the R model has.

I got two pictures of the tracks back and front http://share.pho.to/AC1lW#