Volume VS DB


first, I must say I know very little about audio.
I used to manage volumes of individual audio sources with scripts, to adjust the volumes of background music, sound fx, etc…
Now, I’d like to use Unity 5 Audio Mixer, but I’m a little confused.
Going from 0db to -80db doesn’t give me the same result as going from 1 to 0 with an audio source volume.
At 0.5, you can clearly hear an audio source.
At -40, you can barely hear anything.

I understand Db is not linear. But how can one adjust the volume so that it is somehow linear.
I want the user to be able to adjust the volumes of different channels (i.e.: music, sfx).

Thanks for your help.

Looking further, I could find this, which has solved my issue.