Should I even bother... (1 Viewer)

[Ron Reda]

...upgrading my Monster digital coax to a Bettercables (or something similar) digital coax considering how all that its passing is a bunch "1"s and "0"s?

Also, how about my sub cable? I'm using a Monster THX certified cable right now, but noticed that Catcables.com has a REALLY good price on sub cables.

Thanks!

 

[John Sully]

Nope, it's not worth it.

 

[Mark Rich]

A good digital coax cable will be most noticeable with music rather than movie sound(DD,DTS) Think you can do better than the Monster in this case. Try one of these:

Rhinocables.com

Boldercables.com

Diycable.com

IMO you will not gain anything by going to a tinned copper sub cable. Your Monster cable should perform better. If you want to step up in performance look for a Teflon insulated bare copper cable. Maybe silver with teflon insulation... The teflon really helps with the pitch and tightness of the bass. The above companies sell a subwoofer cable that WILL perform better than your monster cable.

 

[Ron Reda]

Mark,

I'm using a dedicated CD player for tunes, so the cable would be for movies only.

As far as the sub cable, I'll certainly check out those online dealers...I'd like to make the most of what I've got.

Thanks for the suggestions!

 

[DavidSegelstein]

Assuming digital cables are good enough to avoid bit errors, what is the physical mechanism by which one would sound different from another?

 

[Philip Hamm]

I'm using a dedicated CD player for tunes, so the cable would be for movies only.

In that case, definitely do not switch unless you like having a light wallet. The only signal that a digital cable might matter (depending on a host of factors) on is PCM where bit timing / jitter come into play. For DTS and DD you're gold with anything.

 

[JimN]

Assuming digital cables are good enough to avoid bit errors, what is the physical mechanism by which one would sound different from another?

reflectance due to impedance mismatches in spdif and optical quality of cables and connectors in toslink. I also agree with Philip about jitter being more important for PCM but not as significant for DD or DTS.

 

[DavidSegelstein]

reflectance due to impedance mismatches in spdif and optical quality of cables and connectors in toslink.

Wouldn't that have a more incoherent effect than, say, "better bass," or "more transparency," or "better sound stage," or ... I really would like an explanation of the claims I hear and read about subtle differences among different digital interconnects. How could things like impedence mismatches and optical quality of cables affect selected bits in the bitstream in such a way as to change a particular quality of the sound? I'd think there would just be distortion, or worse. No?

 

[John Royster]

David,
Digital audio may be just bits, but the timing and clocking of those bits is very important. The distortion that you would hear would be very slight, but enough to make a trumpet sound just a little off. minor things like that.
As to your original question - only you can decide if it is worth it. For the money however there might be better uses then a digital audio cable - like interconnects.

 

[DavidSegelstein]

... the timing and clocking of those bits is very important. The distortion that you would hear would be very slight, but enough to make a trumpet sound just a little off. minor things like that.

Isn't it buffered on input? I thought once the bit was read, if read correctly, then the timing is only an issue if there is overflow or underflow of the buffer, which is why some DVD layer changes yield freeze frames. And why would a particular cable have any relation to timing? Would a $100 cable introduce jitter, whereas a $1000 cable would not? This gets back to my question - what physical mechanism is involved? What's in the $1000 cable that is not in the $100 cable?

 

[JimN]

This gets back to my question - what physical mechanism is involved?

I answered it above, reflectance. You can choose to believe it or not. There are some very good articles on reflectance and cables. However, the only one in the popular literature I am aware of is in the November 2001 issue of Stereophile by Herve Deletraz.

 

[Philip Hamm]

Isn't it buffered on input?

Good damn question!!! The answer is most often no. Some really high dollar stuff has "jitter filters" (though I believe jitter is more than just bit mistiming, though that is the core of the situation) but it's not common practice to buffer the input on PCM audio. No-one knows why. You can buy aftermarket jitter reducers that perform this function. I have read that cheap cables can introduce jitter but I don't really believe that (though many do). Low quality transports can DEFINITELY introduce jitter no doubt about that.

 

[DavidSegelstein]

I understand that there would be problems if there were jitter and there were no buffering. I also understand that poor cables may have reflectance at interfaces if there were impedence mismatching. One thing I don't understand is how reflectance would be related to jitter, and thus how a digital interconnect can induce jitter. I also don't understand why even a cheap digital cable would not be impedance matched.

I'm still left with the basic questions of 1) what is in a $1000 digital interconnect that is not in a $100 digital interconnect (that is related to sound quality, anyway), and 2) what the physical mechanism is in a digital interconnect that could result in subtle differences in sound quality. JimN, I'll see if I can find the article you mentioned.

 

[Bob McElfresh]

How could things like impedence mismatches and optical quality of cables affect selected bits in the bitstream in such a way as to change a particular quality of the sound? I'd think there would just be distortion, or worse. No?

Try this link for an example of what happens if you use an audio cable instead of a 75 ohm video cable.
http://www.hometheaterforum.com/htfo...threadid=60283
Short Answer: Mysterious drop-out about once every 15 minutes.

 

[Philip Hamm]

Depending on the cable and the system. I've had drop-outs using regular audio cables as a digital coax and I've had perfect performance in different situations.

 

[DavidSegelstein]

Bob, that's very interesting, and thanks for the example. I think I understand this phenomenon, and the physical causes as set out in this thread.

Here's what I'm really wondering about, though. I read reviews of digit interconnects in Stereophile magazine, and I'd like to quote from the descriptions:

Digital Interconnect A ($47.95 per meter) - "... more transparent, more musically honest than any I've heard." [Another reviewer of the same cable:] "... less transparent sounding than the [Brand X interconnect]."

Digital Interconnect B - "Excellent bass performance, with power, clarity, and dynamic contrast."

Digital Interconnect C - "Sometimes mercilessly revealing, but never harsh." [Another reviewer:] "Fast, open, and detailed." [Another reviewer:] "Focused and nuanced. ... Smooth, yet highly detailed, spacious soundstage, and lack of hardness and edge."

Digital Interconnect D - "... midrange liquidity and detail."

Digital Interconnect E - "Excellent soundstage and image focus."

Digital Interconnect F (the most expensive at $1000 per meter) - "Reigned supreme over all ... Bass was tight and controlled ... the midrange was colorful, textured, and graciously harmonic ... although perhaps not as open-sounding as the best ... showing deft charm on less-than-stellar recordings..."

These characteristics are, unlike the example Bob pointed out, not obviously related to bit errors caused by physical properties of the [wrong or poor] cable, with impedence mismatches, reflections, or jitter. I'm having trouble understanding what physical properties could possibly cause differences in characteristics of digital cables such as "nuance" or "liquidity" or "transparency" etc.

Can anyone clarify this? What's different in the $47.95 per meter cable compared to the $1000 per meter cable, keeping in mind that these are digital interconnects.

 

[Chu Gai]

Stereophile, regretfully subscribes to the notion of sighted evaluations and as a result the evaluations are dependent upon the mood of the reviewers as well as what they 'think' makes a good cable. The reviewers are quite taken by what passes as the most recent fad, be it silver, microfinish, nature of the dielectric, a new, never before seen termination, crystalline structure. You name it, Stereophile loves it. Manufacturers of cables are more than happy to send the magazine samples for evaluation because they know Stereophile will never take the time to do a level matched comparison under blind conditions. The more exotic the claims, the more the prose flows albeit it does ring of a Harlequin romance novel. In all likelihood the difference is approximately $950 and under a difference test, I doubt they'd be able to tell the most expensive one from a 20 dollar GE interconnect. Of course that sort of a test is beneath them.

I personally am not aware of the materials used in constructing the $1000/meter cable but I'd hazard to say its cost of manufacture is not proportional to its retail price. Terms such as 'nuance', liquidity, etc. are used for the purpose of making readers think the gentlemen are very naturally intuitive individuals capable of remarkable abilities of differentiation.

For jitter, get the following reprint...

Benjamin, Eric and Gannon, Benjamin ' Theoretical and Audible Effects of Jitter on Digital Audio Quality,' 105th AES Convention, 1998, Print 4826.

 

[JimN]

Nevermind, it's not worth it.

 

[John Royster]

FWIW,

In digital communications the cable is EVERYTHING.

let me repeat - the CABLE IS THE MOST IMPORTANT LINK IN THE CHAIN OF A DIGITAL SIGNAL.

Anixter Labs have continously tested just about every kind of communications cable out there and have the hard stats and measured jitter graphs as it relates to clock speed. Every cable has different results. One can ensure that the measured result meet a certain specification however. But one cannot say that all cables are created equal.

Somehow when we get into audio this fact of electricty and phsics is thought to be meaningless by some. Man I wish I could disclose some of the stuff I learned via non-disclosure agreements.

ps - reflections and impedance vs. length are two of the big variances in cable. Even from the same manufacturer.

pss - as an aside I purchase all kinds of cable used in the tranmission of digital data from 1.5 to 2400 Megabits/sec. no matter if its copper, coax of fiber it is never more than 4 bucks/meter (singlemode fiber). Terminated.

 

[John Sully]

Anixter Labs seems to specialize in data comm and tele comm applications. This is nice, but does not have a ton to do with your digital audio interconnect. For example, assuming that 100/Base-T uses the same BPM coding as SPDIF, this implies a clock rate of 200Mhz, while SPDIF uses a clock of 4Mhz. Obviously cables are going to play a big role in whether or not accurate transmission occurs at the higher clock rates inherent in datacomm applications. However, if a cable meets it's specs it should be capable of transmitting data with an acceptable error rate (btw, the acceptable error rate for SPDIF is 0). Granted that exceeding specs should allow for error free transmission in more difficult situations which should result in higher throughput for network applications.

However, SPDIF is a very different creature. Clocks are relatively slow, runs are quite short in general. In fact, it take more moxie from the cable to transmit a composite video signal (6Mhz) than a SPDIF signal. Basically, we know how to make these cables and know how to make them perform properly. We are not pushing the limits of technology here.

If you can point me to a white paper on the Anixter site which has anything to do with SPDIF transmission I would be happy to read it. However, papers which describe cables effects at speeds ranging up to 50x the clock rate on a SPDIF cable or which describe problems with long runs of CAT5 I have to discount since they do not address the application domain we are talking about here.