The worst "sound system" (widely conceived) for me is the nerve-ripping sound of the brakes of the trains for the Frankfurt subway system (and do these subway drivers have heavy feet!)--the screech can even make the nerves in my teeth hurt on a rainy day. What is curious is how people in the subway try to talk to me through my earplugs (never travel without them), almost magnetically drawn to me for directions and random remarks. There must be some comfort in not being heard. And, to top it off, when the brakes are in high screech mode on the train what does a pale-faced traveller inevitably do, with a look as if they are about to faint or fall dead in suffocation? They open the windows to get some fresh air (one cannot underestimate the irrationality of the German compulsion to "air things out"--the "Beluftungs-Prinzip"), as if there were fresh air 50 ft underneath Frankfurt! Nobody minds as the stale stink of rotten stagnation seeps in and the loudness of the ear-piercing screeches increased to ear-damaging levels. What a rant!