Comments on Profile Post by Taverius

The rough math is that each bit theoretically affords 6db SNR. So ideally you'll get -36dB before truncation.

20*Log[10, 2.^-18] = -108dB

I’m with @famish99 here, although @Cspirou gives the exact expression. But you have 6 bits of headroom, not 18. So 20*log10(2^6) = 36.124 dB. Or as mentioned, about 36 dB

The answer depends. What is min / max if signal distribution in the 24 bit stream? You would be surprised that often there are missing codes and only 12 bits of data used when loudness wars style hyper compression has been employed. Then you can apply considerable attenuation before losing any of the lower level bits. High dynamic range recordings could possibly achieve 21 bits out of 24 bits but this is rare.

For an 18 bit stream would you miss two bits when compared to the CD release version of the same recording? Probably not. Two links that might provide addtional insight:
https://en.wikipedia.org/wiki/Audio_bit_depth
http://www.aes-media.org/sections/pnw/pnwrecaps/2018/oct2018/

Oh sure I agree, you can probably fit that one metallica album in 8 or less. I just eyeballguesstimated that the average good recording + my gear + my ears = everything past 18 is lost anyway.

For any record or time that's truly important I go bit perfect, i just wanted to put bounds on my nervosa for all those other times.

An experiment you can perform for self enlightenment. Pick an album with drum solo. Listen with 12 dB digital attenuation vs 12 dB analog attenuation. Listen for a difference on cymbal texture or graininess on toms, etc. Same for bell like sounds.

I mean, to hear the 21st bit at its intended volume peaks have to be at what 126db? More with dithering. I like my ears too much these days so the LSBs are lost no matter what.

Maybe there's info in the 21st because peaks are very low but eh, attn. is done in fp64 anyway, so it mostly works out for those times when you do want digital attn.

I'll try that out one of these days, though the realities of nervosa mean I'll always turn the digital off for serious listening, no matter what I hear.

If you can stand some electronic music, try Pantha Du Prince/Bell Laboratory: Elements of Light for some hand struck bells and percussion, plus a bell carillon.