Axiom Home Page Forums General Discussion Technical Questions Understanding dB - How much do you need?

I noticed that most of my audio gear measures in negative db when i play with the volume. Why does it to this? Example: my reciever is usually listened to around -26db or less..-28 lets say. But i can crank it up to positive numbers. What does that mean? why don't they just count from 0-MAX like most thing lol (take it to 11? )

Also, how much dB do you actually need in a sub to be able to hear the frequencies, and how does that work with sub20hz stuff that you can't even hear. Is 50dB enough? is 80dB the minimum?

and lastly, anyone have a response graph on the new EP3503

cheers