Head-Fi.org › Forums › Equipment Forums › Sound Science › sound differences in DIGITAL cables
New Posts  All Forums:Forum Nav:

sound differences in DIGITAL cables - Page 3

post #31 of 108
Hey nothing is passing zeros and ones. Digital (non-optical) cables are wires, they carry electrical signals, just like analog cables. Digital cables are supposed to be carrying square waves. They don't quite make it. The receiver can miss an edge, but 3 out of 5 voting usually recovers the one or zero perfectly.

Buffers and plls make timing on the receive side much easier. Still there are hard real-time clocking requirements and if the recieve firmware misses a packet (I am thinking USB audio here) it will carry forward the last packet and you no longer have bit perfect re-construction (but don't worry, you won't hear it). With enough interference you can slow down or distort the square wave enough to cause a problem. About 0% chance this is audible, however. Still I buy reputable cheap cables, not unknowns.

I failed a very careful blind test pitting a radio shack 75 ohm video cable against a $1000 S/PDIF exotic. I was already convinced before that, but this was icing on the cake.

So I'm with the "don't spend big bucks on digital cable" people, although I will not attack anyone who says they can hear a difference. Maybe they can, who knows. But please, no more "it's just zeros and ones", or references to file transfer or other nonesense, or ignoring the real-time requirement on transmission. It's not "bit perfect" we need, it's "bit perfect at the right moment in time".
post #32 of 108
Quote:
Originally Posted by linuxworks View Post
that's why they picked ubiquitous 75ohm video cables and even picked the 'wrong' connector (rca) for the connector of reference. and even with 'wrong' connectors, it still passed bits thru fine.
Standard 75ohm video cables are supposed to work fine, but both times I have had bit errors it was with a video cable. Cheap, but a supposedly proper 75ohm ones anyway.

One thing about comparing cables. I can't find the original article right now, but in some audio forum they made a blind A/B test within last two years comparing coat hangers to some known brand speaker cable. I think this was done right after Randi issued his challenge. The test was done by audiophiles to some extent, not by just mere mortals.

The interesting thing about the test was that the subject was absolutely sure he got every answer right--coat hangers sounded clearly different from the "proper" speaker cable in his mind, and the subject was allowed to listen either cable for comparison at will. However, the test was aborted after seven tries because the real answers were completely random.

This just shows how bad our audiology memory is.
post #33 of 108
Quote:
Originally Posted by linuxworks View Post
I have to strongly disagree.

if there is any audience that uses modern dacs, its THIS crowd and you know it!
I don't think the majority of head-fi'ers use $1000+ DACs.

Anyway, I should be more specific: I heard a clear difference with a cheap DAC, the Zero, and different optical cables. I haven't heard any difference between 75 Ohm coax cables (standard Canare cable and connectors and Van Den Hul) on my Reference 1. However, those cables are coming from a box that converts an optical connection to a coax one, so if anything, it's most likely the digital cable that would have the most negative effect is the optical one, from my experiences and information, from measurements and experiences of others.
post #34 of 108
Quote:
Originally Posted by wavoman View Post
Hey nothing is passing zeros and ones. Digital (non-optical) cables are wires, they carry electrical signals, just like analog cables. Digital cables are supposed to be carrying square waves. They don't quite make it. The receiver can miss an edge, but 3 out of 5 voting usually recovers the one or zero perfectly.

Buffers and plls make timing on the receive side much easier. Still there are hard real-time clocking requirements and if the recieve firmware misses a packet (I am thinking USB audio here) it will carry forward the last packet and you no longer have bit perfect re-construction (but don't worry, you won't hear it). With enough interference you can slow down or distort the square wave enough to cause a problem. About 0% chance this is audible, however. Still I buy reputable cheap cables, not unknowns.

I failed a very careful blind test pitting a radio shack 75 ohm video cable against a $1000 S/PDIF exotic. I was already convinced before that, but this was icing on the cake.

So I'm with the "don't spend big bucks on digital cable" people, although I will not attack anyone who says they can hear a difference. Maybe they can, who knows. But please, no more "it's just zeros and ones", or references to file transfer or other nonesense, or ignoring the real-time requirement on transmission. It's not "bit perfect" we need, it's "bit perfect at the right moment in time".
Finally, someone who understands this.

On the DAC subject, each one of the DACs is subject to some jitter modulation, sans perhaps one of them (AK4396 by AKM Semi). It uses a SCF (switched capacitor filter) and is their supposed "Miracle DAC". I want to try one myself, but I've heard good things about it. Plus it's voltage out, a nice plus.

There are so many things to screw up in a DAC (or anything HF really), so if someone hears a difference, it's worth investigating.
Here's a nice example:
Grounding of Mixed Signal Systems

Hint: A lot of manufacturers screw this up.

~Thomas
post #35 of 108
Quote:
Originally Posted by wavoman View Post
Hey nothing is passing zeros and ones. Digital (non-optical) cables are wires, they carry electrical signals, just like analog cables. Digital cables are supposed to be carrying square waves. They don't quite make it. The receiver can miss an edge, but 3 out of 5 voting usually recovers the one or zero perfectly.... It's not "bit perfect" we need, it's "bit perfect at the right moment in time".
This is true to an extent. The main point of inventing digital audio in the first place was to make it relatively bullit proof against interference when moving it about. For example, yes, the digital signal is supposed to be a square wave but the whole point is that there is a huge margin for error, the square wave can be far from perfect, even significant interference which would wreck an analogue music signal should have zero effect on sound quality in a digital system. Again, the timing issue is in most cases a non-issue. Anyone with a decent quality system or better is going to have jitter rejection mechanisms and anyone with a more budget system is not going to notice the tiny amounts of jitter from a cable anyway.

The AES paper which was quoted previously, gave several potential cures for jitter and that was over 15 years ago, DAC design (and digital audio technology in general) has moved on massively since then.

G
post #36 of 108
yes, I agree that there is a lot of 'slop' in how bad the square wave can be before the audio degrades.

just from personal anecdotal experience, I've ABUSED the poor bits on many kinds of very non-standard cabling for spdif and I have yet to *hear* any negative issue from it.

just for a quick (or not so quick - you know how some test beds end up being more long term than short term, lol) test - I used some junk spare ribbon cable pairs for spdif in a switch I built:







and you know, I still don't hear any problems, even using 'very bad' wiring inside.

spdif is quite robust. much more than people around here want to admit. I don't know why that is, but I guess its always more comforting to find *something* to blame, in your audio chain
post #37 of 108
Thread Starter 
Quote:
Originally Posted by linuxworks View Post
yes, I agree that there is a lot of 'slop' in how bad the square wave can be before the audio degrades.

just from personal anecdotal experience, I've ABUSED the poor bits on many kinds of very non-standard cabling for spdif and I have yet to *hear* any negative issue from it.

just for a quick (or not so quick - you know how some test beds end up being more long term than short term, lol) test - I used some junk spare ribbon cable pairs for spdif in a switch I built:







and you know, I still don't hear any problems, even using 'very bad' wiring inside.

spdif is quite robust. much more than people around here want to admit. I don't know why that is, but I guess its always more comforting to find *something* to blame, in your audio chain
interesting finds linuxworks, thanks for the information and experiment
i guess i expanded my knowledge about digital cables in this thread.
post #38 of 108
Quote:
Originally Posted by Nerull View Post
Grounding of Mixed Signal Systems

Hint: A lot of manufacturers screw this up.
that was a good read, thanks for the link!
post #39 of 108
Quote:
Originally Posted by linuxworks View Post
spdif is quite robust. much more than people around here want to admit. I don't know why that is, but I guess its always more comforting to find *something* to blame, in your audio chain
The only answer that I can think of is the cable retailers. They advertise and highlight deficiencies in cables and formats and then explain how their cables can solve these problems. Their advertising is quite sophisticated, as this advertising revenue to audiophile magazines encourages so called "independent" reviewers to further enforce the idea that cables affect sound quality. I have three serious difficulties with this: Firstly these deficiencies don't have any effect on sound quality so what is the point? Secondly, I've never seen any proof that these expensive cables actually elevate any of the potential deficiencies they are advertising and lastly, the consumer's most easily accessible information is what they have seen in advertising/reviews. It's only really a few people on sites like this who try to fight the misleading advertising and often it's a loosing battle because we are fighting both the advertising/reviews and the flawed but understandable logic that more expensive = better sound quality.

I would have thought after all these years of expensive cables (digital and analogue) that the audiophile world would have taken the lead from the professional audio world and seen through this great cable scam but in fact the opposite seems to have happened. As a generalisation, the audiophile world seems to think of audio professionals as incompetents who don't give a damn about sound quality and professionals think of audiophiles as delusional nutters. So over the years audio professionals tend to avoid discussions with audiophiles, with the result that the audiophile community has even less access to the facts, which of course plays right in to the hands of these rip-off merchants.

G
post #40 of 108
Quote:
Originally Posted by gregorio View Post
I would have thought after all these years of expensive cables (digital and analogue) that the audiophile world would have taken the lead from the professional audio world and seen through this great cable scam but in fact the opposite seems to have happened. As a generalisation, the audiophile world seems to think of audio professionals as incompetents who don't give a damn about sound quality and professionals think of audiophiles as delusional nutters. So over the years audio professionals tend to avoid discussions with audiophiles, with the result that the audiophile community has even less access to the facts, which of course plays right in to the hands of these rip-off merchants.

G
Yeah, that was exactly one thing I had noticed when reading people's bashing. If it weren't my ears, or my mediocre system, or my intellect it were the sound engineers fault that had no idea how to do their work correctly.

They always find an excuse to tell you your system is ***** and you need to spend more bucks in it... If it is not your system it is electricity, that sometimes stops in the middle of the cable, or that doesn't reach all the circuitry of your equipment...

If you think about it they are giving excuses to everything you tell them, regardless if those excuses make sense or are nonsense. Later you realize they have superman ears...

And i have found out that pro equipment is the one that in the end has the best Price/performance ratio. Hence why I bought the amazing Behringer DEQ2496 , and some studio HPs as the Fostex. Their looks sure are not that great, but they perform good.
post #41 of 108
gregorio: I think a lot of reviewers don't have a clue about how digital works. However, on the other hand, I've seen reviews of digital components where the reviewer has said that with a certain DAC expensive digital cables made no difference to cheap ones. It's not a black and white case of the whole thing being BS or there always being merit. From my own experiences I'd be more inclined to buy a better DAC than buy an expensive digital cable. I agree that marketing relies on consumer ignorance.
post #42 of 108
Quote:
Originally Posted by Currawong View Post
gregorio: I think a lot of reviewers don't have a clue about how digital works. However, on the other hand, I've seen reviews of digital components where the reviewer has said that with a certain DAC expensive digital cables made no difference to cheap ones. It's not a black and white case of the whole thing being BS or there always being merit. From my own experiences I'd be more inclined to buy a better DAC than buy an expensive digital cable. I agree that marketing relies on consumer ignorance.
I agree. I was making a generalisation. I'm sure there are reviewers who have a little more integrity, nevertheless, I've totally lost count of the number of reviews I've seen where the reviewer obviously didn't have the first idea of how audio works but that doesn't stop them filling their reviews with pseudo scientific nonsense to cover up their ignorance and to influence others.

I'm with you, if I tried a different cable (power or digital) and heard a difference in sound quality, I would conclude there was a serious design flaw in the DAC and immediately start looking for a new one, as well as contacting the retailer of the DAC and requesting my money back. As I said before, the main principle of digital audio is that it is so forgiving to even quite severe interference. Therefore, if a DAC is sensitive to the tiny amount interference which could be introduced by a cable, then the DAC is not suitable for the purpose for which it was sold. In this country, the DAC retailer would therefore be obliged by law to give a full refund.

G
post #43 of 108
this cable talk is all useless unless we all sit together with the same equipment under the same room

i know what i hear when i switch my coax cables

then again i dont use headphones anymore, gave up on them
post #44 of 108
Quote:
Originally Posted by endless402 View Post
i know what i hear when i switch my coax cables
Unless you have years of training and professional experience, I'm sorry but I don't believe you actually have much idea of exactly what you're hearing. I'm not trying to put you down or be insulting but I hear this argument so often from audiophiles. A number of times I've taken audiophiles into my studio and done various listening tests, while they often have quite accute hearing I've yet to find one that actually had anymore of an idea what they were really hearing than a new apprentice sound engineer.

The world of audio is packed with aural illusion, in fact many roles within the professional world depend almost entirely on the ability to identfy and use aural illusion.

G
post #45 of 108
then why does one cable sound muddy and one cable sound clearer ?
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Sound Science
Head-Fi.org › Forums › Equipment Forums › Sound Science › sound differences in DIGITAL cables