After Audio Mixdown, when I import the tracks into another project, the volume is lower. The pan is centered, and the global EQ is turned off. During mixdown, the faders on the channel volume are at zero. Do you know what this could be? Thank you very much for your help!"
Hi Jan,
I think you have the wrong idea about the concept of Audio Mixdown. I think “Import track from another project” is what you are looking for.
Hi,
yes, that’s what I meant.
Meaning this does not happen if you import the tracks via the “Import tracks from Project” dialogue? Or that it still does happen? 
after importing tracks from another project, they have a significantly lower volume of about 7 dB
Can you post a sceenshot of the original track and the imported track as well as the options you checked inside the Import Dialogue?
What about your pan law settings? This might also have an influence on the level reading.
Also, how did you determine the ~7dB level difference?
To confirm that the audio files themselves haven’t changed, you can select the audio events and open “Audio->Statistics” from the menu.
If those are identical, there must be something different between those projects, maybe the routing, or a plugins?
You’re right, there is a difference in the statistics, but unfortunately I don’t know what caused it?
Yep, these are different audio files. You need to check step for step what you did, and at which point some processing might have happened. We cannot know that.
Apart from that, it is not a big problem, you can just increase the volume of the audio files again.
Hi, so I figured it out. When you use the Convert - Multi Channel to Mono function in a project, then when you do the mixdown of these tracks, their volume is lower. I don’t know why, but that’s how it is. Thanks everyone for the help.
Jan