nscrivener
Member
I was just thinking about the volume control function on my ADI-2 FS dac. It uses a combined analog/digital volume control, it switches between the analog steps and uses digital volume attenuation (the manual says using 48 bits) in between the steps in order to make the volume transitions smooth. It works perfectly and other than an audible click from the DAC when it switches over to a different output you wouldn't know it's there.
I understand the theoretical benefit of this is that it maximises the SNR over a wider range of volumes, combining the benefits of both digital and analog attenuation.
However, is there really any point for this, when the noise level is already below audible thresholds? Yes you might be technically reducing the SNR when you digitally attenuate, but the noise is already below your hearing threshold anyway so how does this provide any advantage from a straight digital attenuation with no analog steps? At 48 bits any quantization noise introduced from the volume control would be miniscule...
I understand the theoretical benefit of this is that it maximises the SNR over a wider range of volumes, combining the benefits of both digital and analog attenuation.
However, is there really any point for this, when the noise level is already below audible thresholds? Yes you might be technically reducing the SNR when you digitally attenuate, but the noise is already below your hearing threshold anyway so how does this provide any advantage from a straight digital attenuation with no analog steps? At 48 bits any quantization noise introduced from the volume control would be miniscule...