20"

D B 72 dB

B E 71 dB

B E 73 dB

A B 71 dB

D A 73 dB

A B 68 dB

C B 72 dB

C C 72 dB

D B 71 dB

C C 70 dB

D A 73 dB

D C 72 dB

C D 72 dB

C A 71 dB

D A 71 dB