Why do digital cables sound different?


I have been talking to a few e-mail buddies and have a question that isn't being satisfactorily answered this far. So...I'm asking the experts on the forum to pitch in. This has probably been asked before but I can't find any references for it. Can someone explain why one DIGITAL cable (coaxial, BNC, etc.) can sound different than another? There are also similar claims for Toslink. In my mind, we're just trying to move bits from one place to another. Doesn't the digital stream get reconstituted and re-clocked on the receiving end anyway? Please enlighten me and maybe send along some URLs for my edification. Thanks, Dan
danielho

Showing 2 responses by dtf

I think that the placebo effect can be blamed for most of it. Analog cables can be very effected by the impedence match with the components they are connect to, and construction approach. Any properly functioning digital cable would be indistinguishable from any other. The only people benefiting from overpriced digital cables are the manufacturers who make them and the retailers who sell them. Let the retailer take a blind test and see if they can really tell the difference.
I was one of the original people to post on this topic, almost 3.5 years ago. My position, that any "properly constructed" digital cable should be indistinguishable from another was predictably met with scorn and ridicule. My ears and even my choice of a mate were questioned. Not that the later has much to do with the topic. Unfortunately, some people when confronted with someone else’s views that don’t agree with their own can’t stay objective.

While I still hold my beliefs, let’s look at some of the other factors that might be in play.

Joemazzaglia makes the point that when he heard optical fiber and coax cable through the same unit, there was a big difference, in favor of the coax. I believe that he heard that difference and it is not surprising. A number of manufactures warned that maximum fidelity could not be obtained from the Toslink connections using their equipment. I believe that is because they hadn’t optimized for optical digital transfer.

There is also the issue of true optical glass cable, vs. plastic. I’ve purchased some true optical glass cables and their performance clearly exceeds a cheap plastic one I bought as a comparison.

I would be interested in whether Joemazzaglia would notice the same difference
if two or three coax cables, all true 75 ohm and made by reputable manufacturers were compared in a blind test? That would say more about the cables, since they are of the same type.

My own experience with a very fine DAC the Levinson 30.6, which has coax (SPDIF), balanced (AES/EBU), as well as Toslink inputs is that the type of cable shouldn't matter. I have compared AES/EBU digital cables from Cardas and Madrigal, with SPDIF cables from Kimber and Madrigal and true Corning fiber optic cables through the Levinson and have not be able to detect any noticeable differences. (The cheap plastic cable notwithstanding)

While none of these cables was a bargain basement item. They are also not cost is no object (or maybe cost is the only object) designs. They are all good well engineered and manufactured products that do exactly what they claim to which is move digital data from one component, the transport, to the next, the D to A converter. They do so properly and predictably and the DAC then can produce the analog signal it was designed to.

I think people need to remember, digital cables transmit 1’s and 0’s. They don’t transmit anything that a speaker would make into sound. That all happens after the DAC converts the signal to analog.

Also, my argument wasn't that any piece of copper wire from Radio Shack will do as a digital cable. I was pointing out that once a design has "got it right", which can be achieved as fairly moderate cost, “Gilding the Lilly” by adding meaningless features (super fancy connectors, braiding around the insulation come to mind) that add cost but change nothing about performance doesn't make the sound better.

I also understand that pride of ownership may make us prefer the fancier cable and if that is so and we can afford it, go for it. But don't try to convince ourselves or others that the sound it can produce changed.

I know that will probably start another round of name calling and if so, so be it. We have a right to our opinions, but I find it discouraging that people attack when confronted with ideas that they don't want to accept. Also too much is made of too little in this hobby. I hate to see folks be convinced that they can buy something that isn’t there if they just spend more money.