Had the radio replaced via TSB#1591078. This was primarily to fix the CD shuffle/tripmeter reset problem. I thought I would mention it as the tripmeter problem is intermittent and some people may not notice it, but would recognize the XM volume problem if they had it. My dealer always gave me the line that "that's the way it is"... not! My XM volume now slightly louder then FM, and on par with the CD player. The quality of sound may be slightly better also ( still varies greatly between stations i.E. toptrack quality sucks, watercolor station ok). Thanks to this forum, I found out about the fix. I bet there are a lot of CTS owners out there that will end up just living with it for the entire time they own the car.
Has anyone else had this issue? My dealer said they had not heard of the XM low volume issue before.
I would love to know if this is "normal" or not? Only way to tell is to listen to other XM enabled CTS' or have others tell me.
Thanks,
Hammer
PS. Part of me is hoping it is "normal"... I am tired of driving over there (takes an hour)...
It is certainly not normal as my 05 had the same problem and I compained since the day I bought it. I eventually swapped the unit for the Navagation unit and the XM sound quality was so much better . The XM now has the same volumn as the Radio & CD and the sound quality also sounds clearer.
My '05 CTS had the low volume XM band problem as well as the trip odometer reset / CD initialization problem. The radio was recalled and I got a brand new unit (reworked SPECMO unit) installed by the dealership under the TSB. Everything works perfectly now
My dealer said it so matter of factly, like it was by design. "The XM is lower and more muted than the FM stations" I thought is was ridiculous, and went aftermarket.
I just upgraded to the NAV unit from the base radio with XM. Although the overall quality is 100x better than the base XM, the stations still vary! If I listen to MIX the sound is just short of stunning... switch to top 20 on 20 and it's $hit!
Must be more of an XM issue than the radio, but the NAV unit must definitely be a higher wattage radio than the base, because the difference is night and day!
The problem is you need to set the Bass, Treble, Etc. for each preset station. Go to each station and set the settings where you like them and then hold the preset button down and it will lock your settings to that station. If you do not re-store the station once you change the settings it and go back to the station it will default to the flat eq settings.
Since Top 20 is your first station programmed I would bet that you set all your settings and stored that station which saved the settings. Then you changed the channel and programmed the rest of the stations with the default EQ settings. You need to adjust the sound setting for each station before you store it.
There is also not wattage difference between the radios since it only uses a line level output to the amplifier and you are using the same amplifier. Ther problem with the volumn is because the old radio firmware had the level set too low for XM. The new firmware corrects the problem and the radio seems so much louder because the level output is higher.
You nailed it... I only had the EQ set to the one station. I didn't have that option on the last radio. I'm gonna go set them in a few. I'm waiting until it gets a little darker to take pix of the LEDs for you compared with the HIDs.
Re: XM low volume fixed! 
