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2 responses to “Does Sirius XM sound far worse than listening to music on YouTube?”

1. 

   Greg Strickland

   September 22, 2023 at 7:09 am

   I vaguely recall reading on “the Internet” the satellite systems of XM and Sirius each had about 3 MB/s of data throughput. As I recall they could use different bit rates for each format channel and bit rate could be day-parted on each format channel. So, a high profile format or show could get reasonable bit rate and sound as good as possible given codec technology of the era. Or, a niche format could have awful audio quality.

   In the merged company I presume they unified the allocated RF spectrum into one service, thus they may have 6 MB/s of data rate throughput. Of course data this data rate throughput number is in the context of coding algorithms of the era. Today’s coding may enable greater data bit rate, and improvement in audio codecs could enable better subjective sound at lower data bit rates.

   In the early 2000’s I got XM for my apartment living room because I thought it would be a nice multi-genre music source for guests. Listening to XM, I was astounded at how bad the audio was, even on the tiny speakers that came with the unit. As a result I never listened to it personally, and eventually I threw it in the garbage, which is basically what their audio was at the time.

   Later I learned that in DC the XM studios were focused on maintaining top audio quality, and they had excellent engineers, and engineering leadership. This makes complete sense, they knew the originating audio had to be best quality achievable, to survive the data rate squeeze of the satellite system. They were being pros, making the best of what they had to work with.

   Thus, the poor audio quality was caused by the company’s decision to have a large number of format channels. They cut the pie into tiny slices.

   Because of the combined RF spectrum and improved data coding and audio codecs, I assume in 2023 Sirius/XM has much better sound quality than I heard on XM twenty years ago. Their main issue may be backwards compatibility with older receivers, but over time, with enough marketing, that can be solved.

   Note that what I read on the Internet or what someone told me may not be accurate.
   So take this post for what it is worth.

   And like many software and tech companies, there are many key technical details they simply aren’t going to tell you. You will be stonewalled and told lies. You have to measure it, deduce it from spectrum use, or try to determine from FCC or other filings what they are doing technically. Kind of like determining where Purina sources dog food ingredients. Good luck with that one.

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2. 

   Doc Searls

   September 22, 2023 at 10:29 am

   Thanks, Greg.
   In their separate days, Sirius and XM used satellites with very different orbits. Sirius’ three satellites had long elliptical orbits that dove low over North America and then far out into space and back again. The three took turns in their low approaches. This system put a much stronger signal down to the ground than is possible with the XM’s satellites. Those, like Dish’s and DirectTV’s, hover in a fixed position about 24,000 miles over the equator, aiming their signals at North America. What difference this made for audio quality and number of channels is moot at this point, because all of Sirius’ old satellites have been put into “disposal” orbits, to burn up in high atmosphere.
   I think the more important question now is how good SiriusXM’s channels sound on its apps. Some compression makes sense, but none require (I would think) the same degree of compression required of channels crammed into a satellite’s feed.

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