Here in the states HD broadcasts are in AC3 Dolby surround or AC3 2 channel with what I perceive as low bit rates to keep the majority of bandwidth available for HD video. Some broadcasts are better than others as far as bass/body is concerned. I use AAC on my DVD rips to my server for DLNA as AAC is better balanced at lower bit rates than AC3 and saves space on rips from DVD masters with poorly mastered audio. On good rips of good source material I haven't noticed any drop in quality of audio using AAC. Perhaps the audio sources used are not very good?