Some of you guys must be using that White Lightening chain lube. My bikes run very quiet. I just lube the chain with 10/40 engine oil. I also put a little into the freewheel. The bikes are true stealth machines. I can sneak up on just about any pedestrian except the deaf, strangely. They keep a good look out unlike most others.
A misaligned chain or a dry chain is the most likely cause of this guy's troubles. The only noise I hear is the wind and a very feint silky sound of the chain caressing the cogs.