XM quality issues in 09 Corolla

[pwain]

Up until this week I had been using a Sirius car kit to listen to satellite radio that i swapped out of my old truck and plugged into the aux. I decided to take advantage of the built-in XM wiring on the 09 corolla and bought the tuner and switched my subscription. (also the sirius car kit died after 5 years of service)

Since then the audio sounds VERY compressed. Talk stations are pretty much unbearable. I don't expect it to sound as good as a CD, but its nowhere near what I had with just a universal Sirius kit. I popped the trunk back open and rechecked all the connections, no problems.

Are there any settings I am missing? I plan to upgrade the rest of the setup at some point, but I don't see that changing anything involved in this issue.

Thanks for any advice that can be given.

[gideon1331]

You are just getting the satellite radio experience. The box for Sirius might have been doing some reprocessing to improve how it sounded, but FM is leaps and bounds better than satellite when it comes to sound quality.

Some math:

Satellite radio has roughly 5 megabits per second of broadcasting bandwidth.

5 megabits per second = 5120 kilobits per second

5120 Kbps / 156 channels on XM = 32.8 Kbps per channel

Now, they claim to use some advanced compression, but 32.8 per channel is a horribly low number, and there is no way you are going to get quality sound.

For an MP3, which is admittidly not as advanced of compression as what Sirius/XM use, it takes 256Kbps for the average human ear to not be able to tell the difference between the compressed audio and CD quality.

Allowing for the increased efficiency of the satellite compression, maybe 160Kbps (arbitrary number...but probably not too far off) might equal CD. In that case you're getting only 20% of CD quality.