ya there is a difference in volume between the two SD vs HD. not sure why about that. the regular season games will almost always be in HD. but, what matters is where ATL falls on the pecking order of games each week. as i remember in 2006 the CLE ATL game in ATL was on CBS but not in HD. I believe it was because networks only have X amount of bandwidth on the signals they broadcast. So, they have to choose the top, i don't know, 5 or 6 games to show in HD and the rest won't be in HD.