So I am into week 3 with my 2015 IS350 Premium (non Fsport) - I have the stock sound system (not the Mark L)...

I find the sound of the radio - Both Sat and FM to be pretty close to very Poor, Playing a CD or musik off a memory stick the sound is great but the Sat and FM are really muffled, low base quality very poor treble. Since the sound system sounds good with a CD or Bluetooth or stick I am assuming this is some sort of reception.processing issue.

Anyone else have the same problem?

Otherwise, still loving the car after 18 days!

 

Satellite radio sucks on any stereo system. For FM, I notice a significant difference when the station is in HD or not; it sounds muffled and low quality when not in HD and becomes clear once HD reconnects. Make sure your HD radio option is switched on.

 

Does it sound worse than AM?
I have the Mark Levinson system, so I know our systems don't sound the same. I sometimes listen to FM and AM radio, but only at low volumes. I would recommend to try this:

Do a scan of all FM/AM stations.
Compare your best sounding FM/SAT station to your best sounding AM station.
The AM station should not sound as good as the FM/SAT stations. If it does, that doesn't mean your AM station is really good. That means your FM/SAT is really bad. If it is, it might be your reception or something else.

If the FM/SAT station sounds better than the AM station, then that is normal.
It really could be that you've been to use to higher quality digital formats.

A couple things to note.
The Lexus cabin has really good isolation. As such, even with the non-ML stereo, because of the cabin isolation, you're going to hear a lot of what the speakers are playing. i.e., no road noise, engine noise, wind noise, or any other noise is going to be distracting you.

With that said, don't forget that the difference in sound quality from FM to CD is bigger than the difference in sound quality from AM to FM. Satellite radio should sound as good as HD radio. That should sound closer to CD than it does to FM radio.
Also, are you using regular FM stations or HD radio stations?

Sound settings/configurations.
The settings are saved per mode. Meaning, if you have high, mids, and bass all on +1, surround sound ON, and ACL ON while playing a CD, those settings do not carry over to all other modes. So I would check to see what the sound configurations are set to while using the radio. And also, play with the surround mode. It does effect the sound quite a bit.

I hope this information could be of some help.
Good luck.

 

My car sound almost the same for CDs, aux, blutooth and FM. I suggest checking the base, mids and treb while you are in radio mode. As aidioqueso said all modes are set up independently and in your case the radio mode seems to be badly tuned.