"Linear-to-GUI" live value -to- understandable dB or amplitude

    Sep 28 2012 | 10:21 am
    I would like to make a max for live device that can offset multiple live tracks volumes at once, given a dB value.
    I managed to get the ids of the tracks I want the volume changed. I currently use a live.observer to get the current volume.
    The problem is that live.observer gives me a "Linear-to-GUI" value (as described in the Live Object Model reference). I can't figure out how to convert this "Linear-to-GUI" value of a volume to an amplitude or a dB value that I can do my math on... It seems that from 1. to 0.85 it goes from +6dB to 0dB and from 0.85 to 0. it goes from 0dB to -70dB
    But even splitting those two cases appart I cant figure out how to get an amplitude or a dB value.
    Any thougths?
    PS : I don't paste my patch since the helpfile of live.observer is pretty much it !