The metal bodied resonator on the widely acclaimed Dire Straits album 'Alchemy' (used on the song Romeo and Juliette) is my suggestion on what is the worst sound recorded. Technically it must be a nightmare to amplify it for a large live venue but all that ended on the tape was a tinny scratchy sound - one that does not do justice to the song or indeed to the band.
So what do you think is the worst sound on record?
Insanity: doing the same thing over and over again and expecting different results. [Albert Einstein]