M.I.T. has two digital IC's that allow you to change different parameters to alter the sound. One goes for $1495 and the other $2995. |
Look at the Cardas Lightning 15 Cable, it is about 200 street price.. Used even cheaper, this is a firehose sized digital interconnect that has a very full bloomful organic sound, super deep bass, and very airy soundstage.... I put this cable in the past against quite a few hi end pieces, including wireworlds top of the line digital which cost a small fortune, yes this will change the sound using certain digital cables no doubt. Why I can not explain. |
It is still a mystery to me that a digital interconnect cable can alter the "frequency response" and frequency/amplitude behaviour of music signal while it is only transporting 1's and 0's. Can anyone explain this? Any expert in the field of digital transmission maybe? Thank you.
Chris |
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 |
Dazzdax, think of digital bits as square waves rising off the noise floor. The noise floor can be raised by reflections and other random noise in the interconnect. The tops of the square waves can be smeared by skin effect. The noise is random, and can sometimes sum up to form another wave that makes it past the threshold (and is read as a bit by the DAC). It may be read as a very jittered 1 where a zero should be. But in any case, it can't be good. |
Amfi, so if a digital cable sounds "different" than other digital cables, even if the sound has a more "natural" presentation (warmer, more fleshed out midrange, silkier highs and greater PRaT), this cable isn't a very good cable in theory because of the time smearing? The next question is: how can one determine if a digital cable is a "good" cable? Most audiophiles are judging by ear whether a cable sounds good or not and not by using oscilloscopes.
Chris |
Dazzdax, you and I and everybody else knows that cable, no matter what type of cable, can not improve the sound - it can only degrade it. As to how you judge a good cable ... well you listen :) I don't go by oscilloscopes either, I go by what I like. Generally if I can hear more detail (not to be confused with treble emphasis) and better dynamics, I know i'm on to the right product. |
Amfibus
your perception of the type of distortion caused by cables is accurate in how it can effect the audio signal. I have found cables to be very sensitive to vibrations caused by the system itself ( feel your cables while the sytem is playing at a realistic level).I was surprised to feel a ton of vibrations going through mine and could only surmise it could effect the audio signal. VD uses some special damping materials the help control these vibes, I also think that solid core cables are less likely to smear the signal than multi-stranded cables ( creating less errors and distortion in the process).I agree that no cable is perfect, but cables that use proven technology help minimise these interactions on the audio signal.Hope this helps Dennis |
