If 0 dB is system volume, and -10 dB is perceptively half that, I'm assuming -20 dB would be half again, thus it would take negative infinity to actually reach "silent".
I understand perceptible "silence" is actually around 30 dB.
How should I set my scale for a volume slider if I don't know what the system volume is? Ideally I would want to have volume at 0% = 30dB and 100% = system volume dB. (under 0% I would use mute)
If I use flat numbers for a decibel scale, it doesn't take into account the target systems volume. For example, if I set 0% volume to -100 dB and 100% to 0dB and have it scale linearly, the audio might already be silent at 90% volume if the system was outputting sound at 40 dB to begin with.
I found this example in the arcade.
scirra.com/arcade/addicting-example-games/941/music-and-sound-example
Moving the music slider around the bottom 40% does pretty much nothing (-60 to -100 dB), the sound is already effectively silent at around -60dB. This is more pronounced when the system volume is lower, and probably varies across systems.
The opposite problem occurs when the scale is set too small. If my 0% volume is -40dB, this might still be quite loud if the system volume was really high to begin with.
Is there any way around this or is this a limitation of not knowing the volume of the target system?
For now I'm setting my lowest volume to -60 dB, but I hope there is a better way.