Which bird am I on?

My new car came with a SiriusXM radio. Long ago I was an XM radio sunscriber because at that time XM had much better audio quality and audio a compression algorithm that made XM sound better than Sirius. With this new radio am I getting the Sirius signal or the XM signal? I see that they still have both Sirius and XM satellites in orbit each using their own technology. I cant get any clear answer from their FAQ. They say there are three kinds of radios, XM, Sirius and SiriusXM, but dont answer what the last one actually is using.

Thx.

SiriusXM has operated ten satellites. You can get details on each one, and be able to track them, at https://www.n2yo.com/satellites/?c=33 -- although the list omits the XM-4 satellite and includes Indonesia's ill-fated Telkom 3. Don't ask me why.

Sirius currently uses satellites FM-5 and FM-6. SiriusXM uses XM-3 and XM-4, which will be replaced, respectively, by SXM-7 in 2019 and SXM-8 in 2020. New model Fords come with a free six-month trial of Sirius All Access. All other new cars equipped with satellite radio use SiriusXM. Unless your new car is a Ford, your signal is coming from XM-3 and XM-4. There is also a "spare" satellite, XM-5, that can be used by either service if one of the other four satellites becomes disabled.

I wonder if they still use AAC+ on the XM Birds and whatever Sirius used to use on the Sirius birds? In the past AAC+ sounded much better. Less swish and more range. I fear that after the merger they are using the same codec on all streams and its is the one Sirius used to use.

I have not used XM since before the merger, but my new car came with a trial and I am curious. It does not sound as good as music on my thumb drive or off Spotify (which I expected and understand)