Reply To: Noise shaped dither – Does it cause issues with DSP-based volume controls?

March 23, 2023 at 12:16 am #5558
Phil Koenig

    My (possibly uninformed) take on this topic:

    I can’t imagine a volume control, digital or analog, that would affect dither or its effect on what is heard.

    You turn it up.  For digital, each sample is multiplied by a constant (giving a constant dB of gain or loss).

    If the gain is negative, the dither level is reduced, possibly resulting (in the worst case) the dither bits being truncated before they get to the D/A.  The situation causes note or reverb  fadeouts to be undithered.  But the fadeout is also quieter, so the quantization noise noise dither is meant to cover is also quieter by the same dB amount.

    If the gain is positive, the dither bits are boosted by the same amount as the program material, leaving the dither in place, albeit possibly no longer in the least significant couple of bits.  But since the program material is also louder, all that has happened its that everything got louder, both dither and program material.

    Feel free to correct me if I got lost in the woods as regards my logic; I’m always open to learning something new.