C A 71 dB

D C 72 dB

C B 70 dB

C C 69 dB

C B 71 dB

C B 71 dB

B A 72 dB

B A 69 dB

B A 70 dB

C B 71 dB

A B 69 dB

D A 71 dB

D B 71 dB

C B 71 dB

B A 69 dB

D B 71 dB

B A 69 dB

C D 71 dB

B A 70 dB