[LAU] Ardour: exporting woes

Hello, This is a soft piece recorded in Ardour. The mix on the master bus sits at around -15dB. That's how it is recorded and it sounds currently nice like this. There's room, nothing is pushed forward in the ears of the listener. After exporting, it sounds like heavy metal, so to speak. So much that there's distortion in the same monitors, at the same volume, that were playing the piece so nicely a minute ago. No more room, no more breathing. Smack. I used jack_capture instead. That kept it as is. 1) Is -15dB on the master bus something completly silly ? 2) If so, how to remediate the currnt recording ? 3) The export stats are: Normalization gain: -14.06 dB Integrated loudness: -12.5 LUFS Loudness Range: 7.6 LU What does it mean when taking into account that the listener will play other tunes and then this one ? Are the numbers telling anything about how it will fit in between other tunes ? The current jack_capture export is at: https://soundcloud.com/nominal6/c2016-05 Cheers.