This is one of my pet peeves. I have no land line and only use a cell phone, and I’m currently on hold with Comcast for a cable problem. The hold music is annoyingly fading in and out. I imagine it’s something to do with the compression used by Verizon.
Is there any chance that the telcos will be implementing upgrades to fix this?
I’ve had problems with on-hold music being incredibly obnoxious in general, and I’ve had problems with the on-hold music being difficult to hear on my cellphone. But the only times I’ve noticed it cutting out and coming back in are when I’ve put the phone on speaker so I don’t have to keep holding it against my ear forever. At those times any random ambient noise - traffic, radio, nearby voices, etc. will cut out the speaker to activate the microphone. They are not both “live” at the same time to prevent feedback.
This may not be the issue in your case, but it’s the only thing I have experienced similar to it.
Hold music sounds like crap because modern cell phone use vocoders to compress the signal so they can get more calls in a given bandwidth. These vocoders are designed to compress speach not music. They also have a very low bitwidth around 13 Kbits/second.