6 speakers in the box can be configured in lots of ways. If all drivers are 16 ohm and are wired in parallel then the impedance of the system would be. 2.67 ohm.

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1/R1 + 1/R2 + 1/R3 +1/R4 + 1/R5 + 1/R6


If the same 6 drivers are wired in series then the impedence will be 96 ohm. You could have three in series (16*3=48) and 3 in parallel (5.34) and the resulting impedance of the system would be 53.34

Or any combination