Originally Posted by dnewhous
I accidentally gave false information because of a bad assumption - they would never offer internet radio service that sounded better than the satellite service.
Whether it is intentional or not the online streaming and DiSH Network/DirecTV qualities may sound better or not depending on the listener. Sirius and XM aren't intentionally trying to make any particularly delivery platform sound better or worse, but they are trying to get the best they can out of all platforms. Each platform has unique characteristics.
For example, DiSH Network and DirecTV have to convert the signal to Musicam (MPEG layer-2) format. The audio source needs to be processed to take maximum advantage of the Musicam codec or it sounds poorly. A similar processing technique is used for the online WMA stream and the online RealPlayer streams, one tuned for the low bitrate service and one tuned for the high bitrate service. And of course the satellite platform using PAC at different bitrates for each class of channel.
XM Radio has a little more work because they deliver over a couple more platforms: XM Online using WMA at low bit rate, WMA at high bit rate, AOL Radio AAC at low bit rate, AOL Radio AAC on high bit rate, DirecTV using one bitrate on Musicam (MP2). And, like Sirius, the satellite platform on AACplus at different bitrates for each class of channel (talk, niche music, pop music, etc.).
The characteristics of the resultant sound are different from the processing and compression used with the codec used on the satellites. I much prefer the DiSH Network/DirecTV audio quality to any other source but that is entirely subjective!!
You should be interested to know that the online streaming channels are all at the same two bitrates. All DirecTV and DiSH Network channels are at a single 192k (Musicam) bitrate. The satellite radio channels are at different bitrates ranging from 16kbps-64kbps. Each platform uses a different codec so the bitrates are only interesting for the bandwidth consumed. Audio quality is totally subjective at this point.