Customizing sound through digital interconnect

Dazzdax, digital cable is even more sensitive to imperfections than analogue cable. For one, the 1's and 0's are square waves, and square waves consist of the fundamental + an infinite number of harmonics (as per Fourier). So the frequencies transmitted by digital cable are in the order of several MHz. Contrast this to analogue cable, which "only" has to deal with 22kHz.

At these frequencies, skin effect becomes more of an issue. Higher frequencies may experience delay in transmission, which would be worse the longer the cable and the smaller the diameter of the cable. This will affect the shape of the square wave.

Also, the cable needs to be impedance matched. If it isn't, reflections can occur in the cable. It is possible to hook up an oscilloscope and see a ghost image of the transmission, which surely can not be a good thing.

Having said this I do not buy into the overpriced cable market. I would only buy a cable which is "good enough". I have learnt my lesson.

My reading suggests to me that the worst source of jitter is in the interface between the transport and the DAC, particularly if you are using transports and DAC's from different brands. For this reason it is sometimes worthwhile to have a one box CD player.

How would you know if a cable is good enough?

Hi Amfi, so you are saying that by altering the shape of the square wave you can change the sonic characteristics of the digital interconnect? Please elaborate. According to the theory digital data stream is either corrupt or not. Digital is discrete, analog is continuous. By changing digital data stream one is not able to predict how the analog music signal will sound.

Chris

Dazzdax, DA conversion is not digital, it is analog. This is not the same as computers, which is not time critical, and if the data is corrupt the CPU can simply request the data again. In a DAC, if the datastream is jittered, it will affect the conversion to analog.

According to my reading (I am no digital engineer) it is possible to smear the square wave to such an extent that it barely rises above the noise, and it is possible to introduce new spurious waves by the summation of reflected waves with smeared waves. You do not necessarily hear a "tick", because this is only one packet of 44,100 signals per second, but if it happens often enough it will change the tone.

Tab110s, I know it is good enough when the next step in improvement will end up costing an unreasonable amount of money.

Hi Amfi, please elaborate the following section:

"...and it is possible to introduce new spurious waves by the summation of reflected waves with smeared waves. You do not necessarily hear a "tick", because this is only one packet of 44,100 signals per second, but if it happens often enough it will change the tone."

I know only a few things about digital data conversion/transmission because I'm a totally uninitiated person with regard to this subject, but if a 16-bits DAC is fed with 17-bits information, I think there would be severe timing problems, if this is possible at all.

Chris