audio amplitude is in %, not in dB
Amplitude is not related in an linear way to the perceived loudness of a sound.
our ears responses is almost logarithmic. i.e. the ear perceive the same diference between 50% and 100 than between 1% and 2%...
With the % scale it is very dificul to adjust low amplidude loudness.
decibels (dB) is the popular scale to control amplitude of sound.
0dB is the reference amplitude (in this context, it's the amplitude of the sound, with no correction)
If a is an amplitude in "a" linear scale then we can define the decibel (dB) amplitude "d" as: d = 20*log10(a) So an increase in amplitude by a factor of two corresponds to an increase of about 6 decibels.
if "d" is the amplidute in dB, the amplitude "a" can be computed with :
a = pow(10,d/20) or : a = exp(d*ln(10)/20)
lot's of information can be find about the dB scale on the internet.
I sugest VLC to allow a control from about -100 to +10 dB