Why do digital cables sound different?

Blues, You are absolutely correct! The purpose of my test was not to simulate the real time data transmission of a digital audio playback system but merely to prove to a poster that the digital cable has little to do with making bits fall out. I chose to do an experiment so I would have physical evidence for what I was claiming and it was fun to do. I do not have the time nor the equipment to simulate a real life situation. I also agree that jitter is not a major contributor. The only thing I do take exception with is your claim that a clock is needed for jitter measurement. A spectrum analyzer can be used to measure phase noise and a calculation can be made to get jitter from the phase noise measurement. The calculation is well documented and the Ma Bells of the world have been useing this method for years. Thanks for your post and happy listening.

Thank you Bluesman, 1439, Gmkowal, Redkiwi and all of the above. The technical data strained my patience, but was well worth following. I am sure that some mysteries will always remain, but with things being this complicated, I will have to continue using my ears as my guide. I wonder if the sound that I prefer would show a smaller amount of the problems pointed out here? Very interesting how small pitch shifts effect the soundstage, Bluesman.

Sorry, I guess we got a little carried away with the technical aspects but I learned alot in this thread and also thank those who enlightened me. The music quickens my pulse but I also enjoy the understanding of how it all comes together.

Daniel,
I've just posted a reply saying that if you cannot hear a difference between a Cardas Highspeed and a Cardas Lightning 15 digital cable, you have a low fi system.I would like to retrack this statement.
What I really meant was, if you cannot hear any difference between these two digital cables, then the question whether different digital cables sound differently should not concern you because you are one of those few in the CANNOT HEAR DIFFERENCE CAMP. In that case, the question of why digital cables would sound different should not concern you either.
Go try out these cables and see if they sound diffently to you and then pursue the balance of your question as to what makes them sound different.

Whether different digital cables sound different is very dependent on the DAC design. Digital cables will typically NOT drop bits. Any degradation has to do with jitter that is introduced due to the cable losses. DAC's that completely re-clock the data stream will be much less sensitive to the quality of the digital cable and any jitter that the cable causes. However, most DAC's are not like this and therefore have some sensitivity to jitter.

Digital interconnects that exhibit low-capacitance, low-dielectric-absorption and generally low-losses will introduce the least jitter into the digital bit-stream.

This is why they sound different.