Reality is a good reason.
Since mmost environments have about 40 to 50 dB of background noise, having a realistic dB setting makes sense.
((Zillions are for fantasy games.))
Then the 'minus' is within the system. The ATTENUATION of the incoming signal is the 'minus' and the zero is the point where incoming and outgoing are (realatively) identical. Then plus dB is the increase over the level of the incoming signal.
Hope this helps to make sense of why it is done.
Since mmost environments have about 40 to 50 dB of background noise, having a realistic dB setting makes sense.
((Zillions are for fantasy games.))
Then the 'minus' is within the system. The ATTENUATION of the incoming signal is the 'minus' and the zero is the point where incoming and outgoing are (realatively) identical. Then plus dB is the increase over the level of the incoming signal.
Hope this helps to make sense of why it is done.