For some time now, I have noticed that some songs, possibly only on the "Solid Gold Oldies" channel, do not sound right. It is as if one of the stereo channels is very faint, or possibly out of phase when mixed to create mono. This has happened on three different TVs, and I even adjusted the balance on one of them to no avail. I switched to Xfinity/Comcast in May 2017, from Verizon FIOS, and the problem may have been there as well. I know that the volume is much louder for Xfinity, so I never have to adjust it above 50%, while I had to use almost 100% with Verizon.
I also notice that the sound seems muffled and distorted, but that could be my own hearing issues. Is there a way to inject pure tones into the coax cable feed to the TV, to see if it is distorted? I could use an oscilloscope and maybe a signal generator into the audio input, but perhaps it is in the sound channel of the video signal?