Pretty simple question, they playback volume in Cubase is a lot quieter than Quick Time, why is that?
So simply starting a new project and importing a finished track plays back much quieter than playing back in Quick Time, even if I push the master fade all the way up.
There shouldn’t be a difference. Some media players have an auto-normalization feature. Make sure nothing like that is turned on.
Quick Time hasn’t got any settings like that, it plays the same volume as Audacity which seems like the correct volume.
Sorry ignore me, it was the control room section in Cubase having a low volume
Then perhaps there’s something wonky with your audio routing in Cubase.
Do you use Control Room in Cubase?
EDIT:
Posted the same time as OP’s above post! 
I do use yes but not for adjusting volume, just to switch between outputs. It must have been set at this low volume a while back and I forgot.