He means looking for something that isn't there (if there isn't any sub content, there's nothing to boost per se, and you might end up with a muddier sound). I did an A-B with the mixes and the new one is definitely louder and crisper. Sounds good. Everyone's going to have differing opinions about it, but I liked the balance between the instruments more in the first mix. The second mix sounds better, listening to it on cheap speakers, but the echoey pingy keys sound a little too loud and the saw sounds a little too quiet. That's really nitpicking though, and again the new mix is louder and sounds good.