the digital preamplifier is operating on voltage (and not power), so 3dB is a halving of voltage level.wrong! every 6dB (i.e. every 12 steps) is halving of the voltage amplitude. You correctly wrote that the digital amp works in the voltage domain & not the power domain but you did not understand that concept fully.
Did you do a sanity check to see if every 6 counts starting from 100 down to 0 would yield exactly 50dB of amplitude control before you wrote you prev post?
We have 100 steps with each step giving us 0.5dB => 50dB of voltage control.
What is 50dB in linear/numeric? 316.22.
So, we can attenuate the digital music signal by a factor of 316.22 using the DSP.
setting 100 = full scale signal amplitude
setting 88 = 1/2 full scale
setting 76 = 1/4 FS
setting 64 = 1/8 FS
setting 52 = 1/16 FS
setting 40 = 1/32 FS
setting 28 = 1/64 FS
setting 16 = 1/128 FS
setting 04 = 1/256 FS
setting 00 = 1/307.175 FS
& 20log10(1/307.175) = -49.75dB, which I'll round off to -50dB, which is exactly the amplitude control range of the digital preamp.