Is it true that optical is better than digital coaxial for audio over long distances (over 10 feet)?
Most of the worlds high speed digital trunks are fiber optic because of their enormous bandwidth, low propagation loss, and freedom from interference from electromagnetic sources and adjacent optical wave guides. None of this applies to your living room. Here, an advantage is reducing the possibility of introducing ground loops between different pieces of equipment – which can be a source of 60 Hz “hum” being introduced in the audio portions of the system. Since there is no direct electrical connection between the equipment items with an optical path as there is with a coax, there will be no ground loop created by this connection (there may be with other connections). I have heard that some folks have had trouble with fragile fibers breaking in home applications, but it seems to me that a well designed optical cable should be rugged enough if it is not abused.
Both of these carry digital signals. So either the signal gets there 100% and is perfect, or it’s going to sound bad and be very noticeable. You won’t see a difference unless you’re going to run your cable all the way to the opposite end of your very large house, and even then there probably won’t be a difference. I will say that optical cables are more delicate and prone to failure.
