Tracks importing at very low gain levels

I am trying Audacity for the first time - I am running Audacity 2.1.0 on Mac 10.11.3.
When I import the voice tracks I need to edit, they are importing at very low volume levels - peaking at only -33. I know they were not recorded at this level as I recorded them myself and they were peaking at -6 to -12 on a professional 6 channel Sound Devices recorder so I am trying to get my head around whether it could be something to do with my import settings - though I didn’t change anything from the default on downloading the software.
If anyone can help, I would be hugely grateful.

There’s only one setting that can change the level of an imported file and that’s in “Audacity Menu > Preferences > Import / Export → Normalize all tracks in project”
Ensure that option is not selected.
(Import / Export Preferences - Audacity Manual)