Nowadays there are much better algorithms to adjust the volume of pieces of music so that they have the same loudness for the listener. These algorithms are now widely used in the broadcast industry and are based on the BS1770 standard or also known under the European designation EBU R128.
Based on my own experience with Traktor and comparing it to other software components, Traktor still seems to use Replay Gain, which is a relatively old algorithm from the early 2000's.
At the link below is an example of how this example was implemented by other music playback software such as Foobar 2000 to get better results according to the BS1770 standard but with about the same loudness as Replay Gain.
https://wiki.hydrogenaud.io/index.php?title=ReplayGain_2.0_specification
