The problem with (some) volume controls done in digital the easy way is that they lose resolution at low volume. The easy way is to shift the sample bits, to the left to multiply the sample by two (+3 dB), or more typically to the right to divide by two (-3 dB). When shifting to the right, you lose a bit (literally, one binary digit) of resolution - it falls into "the bit bucket", i.e. disappears. When shifting to the left, you don't know what to fill in for the rightmost bit, so it gets a purely arbitrary zero, or purely arbitrary one. One seldom knows how a digital volume control is implemented, so the OCD'ers among us avoid using the digital volume controls for serious listening, in favor of analog attenuation.