The software mixer truncates to 16 bits when playing a 16-bit file. This adversely affects the quality of the playback when the volume control is turned down. Please note that the volume control operates in a 24-bit mode when playing 24-bit files and when playing mp3 files. Unfortunately, 16-bit flac and wave files are truncated when the volume control is set below 100%.
Software mixer does not work with Spotify. (known issue)
Software mixer, by its nature degrades sound quality. It’s all explained in the UI. And here:
volumio.github.io/docs/User_Man … ality.html
No, way around that. If you want the highest SQ and ability to change volume, get a DAC with hardware mixing
While a 24-bit volume control is not bit transparent, it is for all practical purposes, transparent.
A 24-bit digital volume control will deliver a 144 dB SNR (relative to maximum output) which is much better than any DAC. The best DACs can deliver a SNR of about 130 dB. This means that a 24-bit digital volume control will not be a limiting factor with any DAC.
However, the 16-bit volume control is a problem. It limits the SNR to about 96 dB. This problem should be easy to fix. Is it possible to force the software mixer into a 24-bit mode? This would fix the quality issue with the software mixer.
Unfortunately no, we’re relying on the very basic (and very obscure) alsa software mixer…