Thanks for these points, but I'm still not sure I understand why my decibel meter on my recording equipment starts off with negative numbers and then reaches 0 and then goes positive.

V

_{db} = 10*log

_{10}(V/V

_{0})

where: V is the absolute voltage level; V

_{0} is the reference voltage level; V

_{db} is the voltage level in decibel.

log

_{10}(X) means: logaritm of X in base 10: 10

^{L} = X where L is the logaritm.

If X < 1 the logaritm is negative. But, in this case, X < 1 --> V < V

_{0}; so, if V < V

_{0}, V

_{db} is negative.