20"

B C 72 dB

B B 71 dB

C D 70 dB

B A 72 dB

B B 72 dB

A A 71 dB

B A 72 dB

B A 71 dB

C B 72 dB

B A 71 dB

D C 70 dB

D A 69 dB

A B 73 dB

B B 70 dB

A A 70 dB

D A 72 dB

A B 71 dB

C B 71 dB

A B 69 dB

A A 71 dB

B B 72 dB