Hello,
I usually normalize audio tracks that I record myself before mixing in my DAW.
But do I also have to normalize the real tracks imported from BIAB?
I imagine not because the realtarck tracks had to be previously normalized by PGMusic.

Thank you for your attention.

There shouldn't be any need to normalize at all if the tracks were recorded at proper levels.

This always fascinates me. I'm not sure whether BIAB has normalized their RealTrack files, but as soon as you adjust fader levels, as is the case in virtually all styles when loaded, that normalization, if any, has disappeared.

I'm pretty certain BIAB uses peak normalization when you export 'flat, dry and centered,' as when I load their normalized files in my DAW they all read at peak -0.5 dbFS.

It is important to know the distinction between peak and RMS normalization processes, as RMS can lead you astray if you're trying to avoid digital overs.

The theoretical ideal file for mixing is peak -6.0 dbFS and RMS -18.0 to -14.0 dbFS. This should make it possible to achieve a good mix not much louder than peak -6.0, leaving room for mastering.

In my DAW I measure every file's peak level and then adjust each to peak -6.0 dbFS. Then I set all faders to -10.0 dbFS. I now have plenty of head room on each fader to easily adjust levels and mix to approximate that theoretical mix peak level. Also, as may not be obvious to newcomers, fader movement is logarithmic with more physical space to adjust faders closer to unity/ 0 dbFS on your mixer.

So while it is true that there is no need to normalize properly recorded files, it is also true that using a system of peak normalization can make mixing easier ... and help greatly when the recording isn't so great.

Further thought. It wouldn't make any sense to have a 'normalization' option when you choose to export 'flat, dry and centered,' if the RealTracks were already normalized.

I never normalize BB tracks.
They come fine right out of the box.
But that's just me.