showing the "tools" column on the last screenshot with replaygain expended might be more relevant if that's what you're using to scan files.
but ultimately it's a matter of what you desire and the most extreme files you own.
as always I'm really not an expert and when it comes to foobar stuff, I'm really just another user so I wouldn't claim that everything I write here is right. hope some more informed people can confirm or correct. and of course Hydro might be the better place if you have super specific questions. although there has been a few knowledgeable dudes helping on this topic
https://www.head-fi.org/threads/the...problems-or-questions-ask-here.624628/page-30
still the principle of replaygain is fairly straightforward even if not super intuitive(I don't know what half of the settings do ^_^). replaygain aims to get some average perceived loudness at a given digital level. so if you set that desired level to 90dB, it will take the super modern and compressed songs that goes to the max all the way, and take it down by almost 10dB so that we perceive the volume around there. logic.
as for very dynamic tracks, the average loudness might be at -25dB before we do anything to it. so replaygain will boost the song by 15dB to reach our 90dB perceived target. that's very likely to clip the song of course. that's where we have to consider what we wish to do.
the most simple choice that solves everything and makes everything at the same loudness is to find the worst case possible among jazz and classical music, and set the replaygain target low enough so that the track doesn't clip. the obvious drawback is that you end up with your favorite Justing Bieber song taken down by maybe 25dB. out of 96dB it's starting to be a lot.
the other choice is to leave it be set the target loudness to something more sensible, and have all the anti clipping options possible, starting with selecting "apply gain and prevent clipping according to peak" on the playback tab. what that will do is say "F replaygain's target level" as soon as a track is going to clip, and make the song quieter so that it doesn't clip. so there you lose having absolutely everything at the same perceived loudness, but at least you don't ruin your song.
you can decide to use other methods, like a dynamic compressor, or just leaving those few clipping ducklings without replaygain tags, or scan them aside from the rest with a lower target loudness, or you could apply a preamp value super low so that nothing clips even with bad replaygain settings... there really are a lot of ways to do things. personally I have -3dB on the preamp but that's for intersample clipping paranoia at the DAC. I use a lot of lossy tracks and I don't use the oversampling option in replaygain(because it's so damn slow) when I scan the tracks. so instead I kill another 3dB from my already crippled dynamic range and put intersample clipping concerns behind me. the lazy way. ^_^
castleofargh modo talking to castleofargh member: stop making off topic posts!!!!!