It's not a matter of adding tags (the only way I know to do that is to save raw DD or DTS files in a special format --SPDIFWav -- that allows FLAC conversion-->tagging. Audiomuxer can do this.*)
It's a matter of having replaygain -- or any DSP -- 'on' in your foobar2K player. If any DSP is active in foobar, the digital output is not bit perfect. DD and DTS (raw) streams have to be a bit perfect for the AVR to decode it. Otherwise, white noise. (This is also why the foobar volume has to at max whenever streaming a DD or DTS file)
*Nowadays since software decoders are excellent and work with DTS 96/24, HD, etc, it's just easier to rip a DD or DTS to WAV-->FLAC and be done with it. But I haven't had to deal with Atmos...yet.)