[andrzejpw]

Well, on my vacation in Poland over the summer, I picked up a few high fi magazines(they had a HUGE review of all the headphones that I might see in Germany on my way to frankfurt/back to the states. My hd580s are fine, thank you.

).

They rated digital cables(toslink, etc). Digital cables sound differently? Huh? They were describing their sound! I mean, isn't a 0 a 0, and a 1 a 1???

 

[carlo]

Physics theory is tricky... yeah a 1mv/100ma signal can pass through a piece of wire without any measurable loss, but our perception of sound is a bit more complicated. Dielectrics, cable length, and conductor material all affect the sound, and most don't have any explanation with mathematical data as proof (although Ray Kimber has some interesting test results).

Following the theory that digital data is digital data, CD players shouldn't have any noticable difference (as Consumer Reports reported a few years ago). However, compare two well built CD players (ie: a Cary 303 and an Arcam FMJ23) and they have their own sound characteristics. But I digress...

The best thing to do is try out cables for yourself and see if you can hear a difference. Why spend the money if can't? And if you can... well, welcome to audio nervosa. We can always use another member.

check your user cp for a PM in regards to test CDs by the way.

best,

carlo

 

[shivohum]

Oh boy this topic and related ones have been debated MANY times on places like AudioAsylum. I'd advise looking at one person's recent questions for an example.

 

[dngl]

Digital is digital in a non time critical situation. There's time to do CRC and it doesn't matter. In audio, any delays, mistimings, misreadings, mistransmissions don't get corrected per se... So you get artifacts and jitter. Better digital cables reduce mistimings, etc.

 

[Russ Arcuri]

For the most part, digital is digital. Period. Rating digital cables is lunacy. Here's a rating for you: Either it works, or it doesn't.

No reputable, reliable test has shown that digital cables, when functioning as designed (i.e., as long as they're not defective), reduce or increase the accuracy of the data traveling over them. If digital cables could change the 1s and 0s that travel over them, the internet simply wouldn't work, and neither would the computer you're using right now to read this.

I've read test reports in which the data was read off of CDs by both super high-end transports and the cheapest low-end CD players with digital outputs. And even without the CRC correction you get with dedicated data drives (CD-ROMs), the cheapo CD players with digital outs performed exactly as well as the $10,000 transports -- all data identical to the source.

Jitter is another issue -- one which can turn into very long, very boring debates. But I'll say this about it: jitter is generally clock dependant -- NOT cable dependant. Good DACs will re-clock the data if there's any concern about jitter.

The audibility of jitter is one of the most hotly-debated topics in all high-end audio. Significantly, jitter in typical amounts has not been shown to be audible in ANY controlled double-blind listening test done that I'm aware of -- and I've done quite a bit of reading on this. People who claim jitter (again, in amounts typically found in even low-cost consumer-grade devices) is audible invariably fail at identifying it in double-blind tests, and typically avoid such tests.

If you accept all this, then, how can the noticeably differing sounds of various CD players be accounted for? Quite simply, there are sometimes noticeable differences in DACs, and in the analog components used in CD players (such as the opamps).

But this was a question about digital cables, and I've probably already worn out my welcome on this particular forum. "Double-blind" is a dirty word on most forums dedicated to "Cables, Power, Tweaks, and Accessories." That's why I don't spend much time here, preferring the other forums here on Head-Fi. Cheers.

 

[Dusty Chalk]

Quote:

Originally posted by Russ Arcuri For the most part, digital is digital. Period. Rating digital cables is lunacy. Here's a rating for you: Either it works, or it doesn't.

Sorry, wrong. Remind me to play this one CD-R in my DVD player (which is not supposed to be able to play CD-R's, because it's one of the older ones). Sounds horrible. Can't say it doesn't work, but there is enough error going on that you can't say it's working really well either. Totally obliterates the black/white argument. If there can be error in the reading mechanism which is neither 100% correct nor 100% incorrect, then cables can do the same thing. Even digital ones.

Plays fine in my el-cheapo Sony, though. I will never give this thing up. CDP-CE525. Carousel.

Now, OTOH, I am still a digital cable skeptic. I use cheap Hosa's (US$10 at Mars Music). As long as they are within tolerance, my system is happy.

 

[shivohum]

Quote:

People who claim jitter (again, in amounts typically found in even low-cost consumer-grade devices) is audible invariably fail at identifying it in double-blind tests, and typically avoid such tests.

See A nail in the bit=bits coffin?

Also, anyone who wants far more information on jitter than I care to learn can go to: http://www.geocities.com/jonrisch/jitter.htm

 

[aos]

>Sounds horrible

That particular problem is most likely because there are too many errors during reading (because the CDR is not reflective enough at the wavelength of the laser used for reading DVD/CD, some DVDs have twin lasers for that reason). CRC can fix errors if the error rate is below certain value and is meant to fix errors due to dust and scratches, not media incompatibility.

Digital cables could sound different, not because of 1's and 0's would get misread but because of jitter. Digital circuits will tolerate it as long as it doesn't interfere with detecting 1 or 0, and the margin there is pretty wide. That is not to say that jitter doesn't matter in digital world, when you get to high bitrate multiplex systems in gigabit range especially jitter can be very disruptive and is being considered in all designs. However, while the digital logic will work just fine, when the signal gets to the DAC, the issue of when the transition from one bit to the next occurs becomes important, probably because of the way DAC chips work. While digital circuit may take the value of the signal some time after the edge or even in the middle of clock cycle and be totally immune to even quite high jitter, you could easily imagine DAC holding the analog equivalent of sample when the clock edge marks the end of the word (after some delay naturally) and until the next clock edge arrives. Variations in between-the-clock-edge times would be directly visible in output signal and supposedly people can hear the byproducts of much less jitter than digital circuits care for.

If the digital cable is not impedance-matched to both output and input, the reflections caused by it will add to the whatever jitter is already in the signal. So will the interference if the cable is not well shielded. But even if the cable is perfect 75Ohm - and even few percent variations will cause significant reflections - no one guarantees that the transport's out is exactly 75 or that DAC input has proper termination, and they're all different. I could easily imagine an imperfect cable sounding better just because it is better matched to imperfect device terminations. Or because the jitter it creates interacts with jitter originating from transport and its dirty clock and moving the byproduct distortion to different frequencies or out of range. Who knows? But I am sure it can all be scientifically explained.

I personally, however, have never heard any difference in digital cables.

 

[Tim D]

I'd also agree about it not being so black and white yet I also would only get any affordable digital cable that is competent.

For example EVEN data read off my supposedly good enough CD-rom's with some CDR's can without a doubt non-subjectively SHOW poor reads, and require re-reads. There is no TIME for such events for 99% of the audio cd-players out there to churn up the CD-R again and reattempt a re-read. Also a 52x spinning CD-rom has a much higher mechanical noise than any audio transport. If people were asked which portable units were quieter, those that spun constantly, compared to units that spun up quickly and spun down...it'd be the older units that are mechanically quieter.

As for reclocking...it is not that easy or cheap or common although I wish it were. The type of pro-audio hardware where you can set master or slave clock settings is also not very cheap. Typical consumer transport dac topology's usually rely on the transport for the clock coming in through the cable and no reclocking is done. I get a couple of pro-audio catalogs like Fullcompass so I actually see that it isn't very common nor cheap.

Quite simply, it isn't only the issue of getting one parsel from point A, to point B, but getting thousands of parsels from point A to point B within very limited timeframes.

As for the audibility of jitter...its one of those things that influences the overall character of the outputs...hence pretty hard for most people to hear a player and tell instantly "wow this has way too much jitter". But likewise I've always heard flywheels from TV's or monitors...but never would I be able to say "you know I hear a 16khz signal emitted from that TV". At least not until NOW Muahahahha!

My only point being...maybe we DO hear it...we just don't know what IT is yet. BTW sometimes pops and clicks in computer audio can actually be a symptom of very severe form of jitter.

I am aware of constraints however also practical enough to know that digital audio probably has less variation in terms of jitter, than even the wow or flutter of a cassette deck. But I'd bet digital audio has less tolerance as well. In anycase, I believe in "good enuff", which to me would be my D/IO and Denon...which to me often gives me a performance of more than good enuff especially for the price.

BTW...the D/IO I believe is able to act as the master clock but does NOT support reclocking functions. I get an indepth perception into the audibility of jitter and it truly is educational. I have found that when the D/IO is set as master (which it shouldn't be because it does NOT reclock), it will STILL produce music in either 44.khz or 88khz modes. To MOST it will be flawless. I have personally found that it is not flawless compared to external sync for me...and that the flaws are made much more apparent in simple sine tones than complex music arrangements. And that these pops and clicks that I hear are random and occasional. Of course this is an instance of making the constraints of jitter more audible than they typically would be in a correctly setup system(cause the D/IO outputs noise whenever it doesn't get a packet at the exact right moment). This jitter issue actually seems lessened at 88khz than 44khz but I'd have to recheck. Setting it to external sync obviously clears up matters, however "synching" is not equivalent to reclocking.

Oh and the proaudio gear that I've seen that DO reclock and claim ultra-low jitter? Not cheap. And this is a pro-audio not audiophile catalog.

 

[aos]

>As for reclocking...it is not that easy or cheap or common although I wish it were

That's true. But if you're willing to DIY, there are a couple of projects doing reclocking out there. Or if not, it is probably enough to just upgrade clock in your transport, and far easier than making a DAC, too. I'm hoping to test what it' all about in the very near future as I just received some low jitter clocks I've been waiting for ages...

 

[Hirsch]

I used to be a digital cable skeptic. Tried a bunch of them and couldn't hear a difference. I then tried a good silver cable on a whim (Elco DC-32 was at a good price when it was discontinued), and there it was. A huge amount of detail had been missing, in cables from Acoustic Research, Audioquest (Digital II), Bettercables.com, a couple of Toslinks, and several others. I'm not a skeptic anymore (and I've got a half dozen of the Elco's).

 

[andrzejpw]

I'll take you word for it. I'm using 3 digital cables. 1 coax(its actually a plain video rca cable), 1 tos to tos (dvd to hometheater, it was a cheapie, like $20), and 1 tos to mini(came with MD).

 

[Russ Arcuri]

*Sigh* Why did I get involved in this?

Quote:

Originally posted by DustyChalk If there can be error in the reading mechanism which is neither 100% correct nor 100% incorrect, then cables can do the same thing. Even digital ones.

No -- in this case, B does not necessarily follow from A. The reading mechanism may or may not be capable of reliably detecting the "pits" and "bumps" in CD-Rs because the wavelength of the laser is borderline for reflectivity on CD-R media. So some are read correctly, and some aren't.

Digital cables are simply transmission media. I'll admit that it's possible for an optical cable to be damaged in such a way that there is some percentage of packet loss at the receiving end -- but that's totally irrelevant to the original argument. If a digital cable is not defective, it cannot "sound" any better (or indeed, transmit data any more accurately) than another non-defective cable. Rating them for sound is like rating a floppy disk for the picture quality of the .jpg image stored on it. "Hmmm... the reds are overblown and the contrast is too high in her face... Try storing it on a Maxell floppy instead -- Memorex floppies usually impart a red tone and high contrast."

 

[morphsci]

Although 1's are 1's and 0's are 0's in coaxial capable impedance mismatches either within the cable, at the cable connectors or the source or input connectors can all result in "parasitic echoes" and cause signal smearing or if large enough, data errors. You can also get echoes and reflections in optical cables because they are not all equal in fiber optic quality nor in their connections. In a perfect world digital is foolproof, but who here believes we live in a perfect world?

BTW cables are not transmission media they are, and function as, transmission lines, as very eloquently described and explained by Herve Deletraz in the Nov. issue of Stereophile.

 

[Russ Arcuri]

Quote:

Originally posted by shivohum See A nail in the bit=bits coffin?

What you quoted was an unsubstantiated account of someone who claims to have done a double blind test showing obvious differences between transports. I can point you to web sites with sincere accounts of people having meals with bigfoot too. How is it that some guy on the internet is able to get 100% accuracy in a (supposedly) properly-administered double-blind test, when digital audio professionals have been unable to do it in years of trying?

Quote:

Originally posted by Hirsch I used to be a digital cable skeptic. Tried a bunch of them and couldn't hear a difference. I then tried a good silver cable on a whim (Elco DC-32 was at a good price when it was discontinued), and there it was. A huge amount of detail had been missing, in cables from Acoustic Research, Audioquest (Digital II), Bettercables.com, a couple of Toslinks, and several others. I'm not a skeptic anymore (and I've got a half dozen of the Elco's).

If this difference in sound can be detected in a properly-administered double-blind listening test, then either your old cables or your new ones are defective.

Look, I apologize for getting involved with this thread. I'm not criticizing anyone for buying whatever they want. If they believe it changes the sound of their systems, great. They're happy and what I think shouldn't matter. But there's no way this debate can be settled here when it's been argued for so long by others. I'm out of here...