18"

B A 71 dB

B A 70 dB

B B 72 dB

C A 72 dB

C A 73 dB

D C 70 dB

B A 69 dB

B A 71 dB

B A 71 dB

B B 72 dB

A B 72 dB

C D 73 dB

D B 72 dB

C B 73 dB

A C 70 dB

C B 70 dB

D A 71 dB

C B 71 dB

C A 71 dB

D B 71 dB

B A 70 dB

C A 72 dB