I'm not a pilot and do all of my ATC listening on the ground with quality receivers and external aerials. Until quite recently, radio reception on the Leeds Radar frequency was usually quite poor and I'm only about a mile from the airfield. Tower and Delivery are consistently strong - 5 plus, if you will - as was the back-up radar frequency but Radar was often accompanied by white noise and occasional static. I don't know what was wrong but these issues seem to have been eliminated, having been around for a few years. There were a handful of pilot reports I remember hearing. I still hear background noise and faded speech with some controllers but that could be a microphone problem.
Incidentally, I am always impressed with the RT technical quality at Manchester Airport. Controllers' speech is always very full-sounding, punchy and clear with the right bass and treble balance. Never any background noise or other audio nuisance.