All digital volume controls perform mathematical calculation on the digital data representing the analog audio signal. Although complex in practice, it's easy to understand in principle. Reducing the volume in the digital domain is accomplished by multiplying each sample by a number less than one. Let's take the example of decreasing the playback volume by 6 dB. Because 6 dB represents a halving of voltage, every sample is multiplied by 0.5. The samples encode a number that represents the original analog waveform' s amplitude at the time the sample was taken.
Dynamic range is reduced, and the music signal gets closer to the digital noise floor.
With fewer bits, low-level signals can become more coarse, particularly at high attenuation levels. Losing a little resolution from 21 bits is an acceptable situation, Wadia believes. Second, every Wadia product with digital domain volume control provides variable analog output level via switches inside the unit. Setting these switches gets the CD player's analog output level in the ballpark so that very little digital domain attenuation is required. Third, Wadia sontends that the slight degradation imposed by the digital volume control is vastly less than the effect of an analog preamplifier and a pair of interconnects.