Amplitude to dB formula


    Feb 12 2013 | 5:18 pm
    I want to control send/return dials with [live.remote] through amplitude values. For that I need to know what formula Ableton Live uses to go from 0-1 to dB values. Unfortunately it doesn't use the same formula as [atodb]. Does anyone know?

    • Feb 13 2013 | 5:26 am
      it probably uses the same formula, log 10 / 20, this is what all audio apps use.
      but most audio apps also use custom scaling of the user interface sliders - typically the lower end is scaled in a curved way to give more control over the lowest 30 dB/A.
      this is probably what you are seeing.
    • Feb 13 2013 | 7:37 am
      Yes. The first half is curved, up to -20db. And from -20dB to 0dB it's linear. But I'm struggling with the curved part.
    • Feb 13 2013 | 7:55 am
      This comes pretty close:
    • Feb 14 2013 | 1:29 pm
      I have come to a solution. Here's the lookup table to control sends with exact amplitude values.