The mix sounds great, has good volume in my headphones. But after I burn a CD and play the CD through stereo speakers, the CD sounds weak, low volume.  The meters on the Console are at good levels.  I've applied Boost 11.
What's causing the CD to sound weak?
 
I'm using a Yamaha Audiogram 3 audio interface, Sony Viao I5, Windows 8, Sonar X2.