In-car comparison of XM & Sirius

HomieG

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Oct 13, 2008
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I finally got around to installing a docking cradle for my Sirius Brix Streamer Replay in my new truck. The truck also has XM which is currently on a 3-month trial. I plan on letting the trial lapse when its up, and using the Sirius radio which has a lifetime sub on it.

To me the audio quality sounded the same on those channels which were duplicated on Sirius and XM. Interestingly, I found the Sirius audio lagged the XM audio by about 4-5 seconds.
 

semipenguin

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Oct 11, 2008
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I noticed the lag years ago when I'd listen to ESPN Radio...:right:
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IdRatherBeSkiing

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The lag is dependant on the channel. Try a NY based channel like the 70s and the lag would probably the other way.
 

snakester

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Oct 29, 2008
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Lovely Seacost NH
One thing I noticed when I was a dual sub was the dropouts tend to be less jarring. XM has sort of an "error compensation-comfort noise" style system, where the last couple of frames of received audio are echoed out into white noise, and the radio keeps track of where in the stream it was, resuming at the right place.

Sirius dropouts, on the other hand, the radio seems to just decode whatever's thrown at it, including error bits, making some ungodly, deafening noises at times. There seems to be no form of error compensation, just a jarring, off of the edge of a cliff type noise. There's also no time code in the audio, resulting in time differences in when the audio comes back, sometimes by a second or so, really being inconvenient when you're tring to sing along with the songs! The only real advantage of the sirius platform I can think of is the fact that it was designed for more than 16 letters, but XM overcame that limitation later on.

XM seems to have the superior sound quality now, being a lot less swishy then sirius, and their processing has overcome most of the problems inherent with SBR.


The lag is dependant on the channel. Try a NY based channel like the 70s and the lag would probably the other way.
Howard 100 is from NY, and it's still a bit delayed on Sirius side.
 

downsj

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Nov 17, 2008
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Around here, XM drops out considerably (at least 2x) more than Sirius. It's extremely annoying.

I would never buy an XM radio as a result, it's Sirius or nothing for me. XM's sat coverage just isn't as good.
 

IdRatherBeSkiing

Sherbet is NOT and NEVER WILL BE ice cream.
Oct 11, 2008
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Howard 100 is from NY, and it's still a bit delayed on Sirius side.

That makes no sense unless they are feeding the NY feeds to DC then back in bulk to NY for uplink.

Just checked the 70s and it is also delayed. This does appear to be what they are doing.
 

DAB

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Oct 9, 2008
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That makes no sense unless they are feeding the NY feeds to DC then back in bulk to NY for uplink.

Just checked the 70s and it is also delayed. This does appear to be what they are doing.

It has always been delayed even before the merger, so I don't think you are correct.
 

IdRatherBeSkiing

Sherbet is NOT and NEVER WILL BE ice cream.
Oct 11, 2008
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It has always been delayed even before the merger, so I don't think you are correct.

Before the merger they were not playing identical streams. There was no concept of being 'delayed'. An XM radio is always about 2 seconds ahead of a Sirius radio playing the same channel.