I have often noticed that, whenever a race bike is running with free wheel (so no active pedals movements), I can hear a distinct "tick tick tick tick" coming from the rear wheel, sounding more or less like a speedy clock.
That doesn't happen neither on my cheap city bike, nor on my more expensive tourism bike. Is it a matter of proper lubrication, or is it also an indirect index of how good the gear is?
I would guess that if I hear a sound, some energy is being spent to generate it, and that energy comes from the bike motion. Therefore I would assume that a better bike with lower resistance would be more silent.