# SPDIF: Coax vs optical



## Scali (Aug 25, 2008)

My brother, who considers himself an audiophile, claims that coaxial SPDIF sounds better than optical, and I should replace my optical SPDIF links with coaxial ones. He can't really name a valid reason why this would be the case, but he gets upset when I don't take his opinion as fact.

I, being a software engineer and having lots of experience with digital signals, say that's nonsense... digital signals are very forgiving in terms of noise, so the medium doesn't really matter, as long as the receiving end can still make a 0 or 1 out of it (and something needs to go REALLY wrong if it can't, at which point you probably get major dropouts in the signal right away, instead of minuscule signal degradation like in analog signals).
In fact, optical cables have an advantage over coaxial because there's no direct electric connection. This means there's no chance of ground loop problems (especially computers seem very sensitive to that).

Is my brother on crack, or has anyone here heard the same argument that coaxial links are better? And if so, why would they be?
I use both, because not all components support optical, but I've never noticed a difference in quality. Not between cheap or expensive coaxial cables either.
Ofcourse I could just be deaf


----------



## Ishan (Aug 25, 2008)

There is no difference, any data loss would be heard as a click as there's about 0 redundancy in the SPDIF bit stream. I've heard clicks with very poor and long coax cable, never with optical, even with the crappiest fiber I could find 
So yea he's saying crap, like most of those so called audiophiles he believe crap invented by companies, and swear by it to justify spending tones of money for "the ultimate sound".
They are right to some extent, hi end tube hifi with hi quality speakers does sounds far better than your average so called "hifi" piece of crap you can find in every wallmart but most of them don't even know what they are talking about most of the time because they "believe" something is good, and didn't use scientificly proven fact to back it up.

Man... do I sound hateful  but yea, I clearly hate those guys.


----------



## Scali (Aug 25, 2008)

Yes, the placebo-effect reigns supreme among audiophiles. They're not a very scientific bunch in general, and they can't prove many of their theories, but still they think they're right all the time, and they the authority on audio 

Anyway, the only technical explanation I can find for coax sounding better than optical is when somehow the conversion between electrical and optical signals is somehow unreliable. But I find that highly unlikely. In fact, if optical cables had any problems whatsoever, I guess they'd have been phased out long ago, because nobody would accept their (semi-)professional digital audio equipment to have any kind of clicks, rattles or whatever in their signal.


----------



## Matt Crooks (Aug 25, 2008)

Your brother is on crack.

Cocaine is a hell of a drug.


----------



## Ishan (Aug 25, 2008)

The funny thing is digital signals are far more resistant to noise than analog, I'm laughing every time I see an old dumb ass buying a 1m HDMI cable from Monster Cable (it costs as much a 130&#8364; in some shop) and knowing he won't see any difference between this and the cable I use (5&#8364; 1.8m no name cable  ).
As long as the cable is properly shielded and you don't have to run your signal for more than 20m there's no need for anything special, they'll never learn...
Same goes for Coax audio cable, do I buy a 3m "HQ" coax audio cable for 50&#8364; or do I buy a 10m video composite cable for 10&#8364;? (basically the same cable with another name  )


----------



## darren (Aug 25, 2008)

Data is data. As long as the digital signal arrives with all its bits intact, there is absolutely NO difference from one transmission medium to the next. Your brother needs to think more logically about it instead of listening to audiophile bullshit. There's probably error correction built into the S/PDIF protocol.

Ask him if he thinks his porn looks better when he's using a hard-wire oxygen-free copper Ethernet cable with gold-plated connectors to hook up to the Internet vs. a wireless connection.


----------



## John_Strychnine (Aug 26, 2008)

I work for a fibre optics company and tbh there isn't really any difference. 

Quality of the fibre obviously changes the speed of which the data arrives on the other side. But in the case of spdif, as it's only sending data as 0's and 1's, you could use chain of paper clips and get the same results.... 

Which is why expensive HDMI cables are a complete con (people actually spend £300 on a data cable?)


----------



## Scali (Aug 26, 2008)

Well, HDMI is a bit different. SPDIF is a relatively low-frequency signal, over a single line. This means it doesn't rely much on the cable quality.
However, with HDMI you have a lot of data lines right next to eachother (which means that each signal line is generally much thinner and less shielded than in your average coaxial spdif cable), and the signal is sent at much higher speeds.
This means you'll run into problems sooner with HDMI, the electric properties of the cable become important again.

I suppose you can think of the digital signals as block waves. As guitarists probably know, cables have a capacitance... Basically they work as a capacitor, with resistance, which comes down to a low-pass filter. Longer cables will drop off more high frequencies (although the effect with a guitar is worse than with most other equipment, because a guitar is a high-impedance passive circuit. With active electronics like EMG, cable length matters a lot less, the signal is 'buffered').
When the data rate is very high, you are basically sending a very high-frequency blockwave signal over your cable. Now, when the cable is very long, and the lines in the cable are low quality, the capacitance of the cable might not be sufficient to properly transfer the high-frequency data signal.

I've actually seen this happen with HDMI/DVI cables. The cables would work, but only at lower resolutions/refresh rates. At higher settings, you'd get pixels or lines dropping out, or just completely losing image.

Ofcourse I'm talking about long cables here, over 5 metres, which you generally don't use around the house. With just 1-2 metres like you'd normally have from your Blu-Ray player to your TV and such, this issue is virtually non-existent. No cable is THAT crappy 
So there is *some* truth to quality of HDMI cables, but nothing like what Monster Cable wants you to believe 

A similar example is with harddisk cables in the computer. They used to have a parallel interface, with 40 lines. As speeds increased, they decided to make each line double, so you got 80 line cables, connected to 40 pins. This cut down on interference. Then when ATA133 speeds were reached, Intel decided they were not going to support it, because in their opinion it wouldn't be reliable enough (longer cables or poor quality cables could cause data loss). So we moved to a serial interface at some point, which could support high speeds more reliably (much like how the parallel printer interface is dropped, and USB replaced it, being a serial interface).
Or CAT5 cables used for ethernet, they shouldn't be run over more than 100 metres, because you'd get data loss.
So there is SOME concern about cable quality even in the digital world. But in general the impact is much lower.


----------



## Ishan (Aug 26, 2008)

I have a 5m low grade DVI->HDMI cable and I assure you the data transfer is just perfect. I don't think you'll see any drop out/click under 20m of cable...


----------



## Scali (Aug 26, 2008)

Ishan said:


> I have a 5m low grade DVI->HDMI cable and I assure you the data transfer is just perfect. I don't think you'll see any drop out/click under 20m of cable...


 
At every resolution?
Wikipedia actually goes into this problem:
High-Definition Multimedia Interface - Wikipedia, the free encyclopedia
There are different categories of cables, for different lengths/resolutions.
As they say, under 5 metres, virtually any cable should work. Once you run longer, you need category 2 for high resolutions (up to 1600p). 12 to 15 metres is about the maximum you can go.


----------



## drmosh (Aug 26, 2008)

Your brother is a nutter, with a signal as simple as a SPDIF signal there is no difference at all. 
you should do a double-blind test actually, to prove to him that he cannot hear any difference at all.


----------



## Ishan (Aug 26, 2008)

I mostly use 1080i/p, I once tried a 10m cable with no problem (running 1080i)


----------



## Scali (Aug 26, 2008)

drmosh said:


> Your brother is a nutter, with a signal as simple as a SPDIF signal there is no difference at all.
> you should do a double-blind test actually, to prove to him that he cannot hear any difference at all.


 
Yea, but even that won't convince him.
What amazes me most is that he can name absolutely no reason, absolutely no source for this notion that coaxial spdif would somehow be superior... and even though there's plenty of evidence to the contrary, he insists.
Where does he get that idea in the first place, and since it's apparently based on nothing, why does he insist?

He has these things... He was also convinced that by the start of 2008, analog TV would be removed from the cable, and everyone had to go digital. I asked him where he got that from, because I had not received any information on it from my cable provider, and I couldn't find any mention of it on their website either. He couldn't answer it, but he insisted.
Needless to say, the analog signal still works fine on the cable today.
The closest thing I could find is that the European Union strives for digital TV by 2012, and there are a few countries that are pushing it actively, but not us (yet).
So basically, if I had believed his nonsense, I would have bought a digital cable tuner for no good reason.

I just don't understand people that defy logic like that. Are all audiophiles this way? I know a few guitarists that are like that, but audiophiles seem even worse.


----------



## Ishan (Aug 26, 2008)

Not all are like that, I know a guy whom I consider an audiophile (he build his own hifi tube amps and speaker cabs) but he doesn't fall for hyped stuffs said by magazines/internet/amp makers/etc...


----------



## Scali (Aug 26, 2008)

Well, I've come to associate the term 'audiophile' with the snobby know-it-all types that talk out of their arses, claiming they have 'golden ears'.
Sort of like wine connoisseurs, who can talk for hours about a glass of wine. It's funny when such people have to do a blind test between a cheap wine and an expensive one, and choose the cheap one 

Personally I already think tube amps for hifi sound is nonsense. Transistor amps have better dynamic range, frequency response, less harmonic distortion and better signal-to-noise ratio. As such it is a simple scientific fact that transistor amps have a more natural, transparent recreation of recorded audio. The only thing one can say is that it 'sounds better', which is ofcourse highly subjective. It is a fact that one can record tube distortion and reproduce it on a transistor amp, therefore any tube distortion or other 'analog' side-effects to enhance the sound can be added at recording/production time. So if the artist didn't add it, it wasn't supposed to be there, and I'd like to hear the music as the artist intended (same goes for digital effects for reverb, surround etc built into a lot of amps these days). If you want to hear more distortion, noise or other side-effects than the artist intended, that's your choice ofcourse.
Guitarists use tube amps for different reasons, that's a different story.


----------



## Ishan (Aug 26, 2008)

I find tubes sounds better for hifi, the added distortion is pleasing to the ear as opposed to SS distortion. In term of dynamic, nothing can come close to a really good hifi tube amp honestly.
Being neutral, transparent, or low distortion blablabla is not important, your ear is the judge


----------



## Scali (Aug 26, 2008)

Ishan said:


> I find tubes sounds better for hifi, the added distortion is pleasing to the ear as opposed to SS distortion. In term of dynamic, nothing can come close to a really good hifi tube amp honestly.
> Being neutral, transparent, or low distortion blablabla is not important, your ear is the judge


 
I think you missed my point.
My point is that if you add tube distortion to the recording, a SS amp can reproduce that accurately (and various CDs are produced with actual tube distortion or modeled tube distortion).
Pretty much any 'analog' type of distortion/noise/etc can be recorded and reproduced with an SS amp. Distortion, compression, noise, static, you can add it all if you want. But you also have the option of leaving it out if you want.
So you can get any tube sound you want out of an SS amp, but you can't get an SS sound out of a tube amp (I could imagine that something like dance/house music won't sound very good on a tube amp at high volumes, because the amp will compress and distort the bass drums and such, losing the punch and tightness that this music is famous for).

SS distortion might not be pleasing to the ear, but the level of distortion on a good amp these days is too low to even notice (we're talking like 0.001% THD or better). So that argument simply doesn't hold.
I think it's no coincidence that even in the higher regions of consumer audio, tube amps are all but gone. A good tube amp doesn't have to cost all that much, no more than a high-end Sony, Yamaha, Denon or similar SS amp. Yet it's the SS amps that have taken over the market. Most brands haven't made tube amps in decades (unlike the guitar world, where tube amps have survived despite SS amps, hybrids like ValveState, and digital modeling).

What exactly do you mean with 'dynamic'?


----------



## darren (Aug 26, 2008)

Anyone with an "audiophile" in their circle of family or friends should read this:

Experiments: Do Coat Hangers Sound As Good Monster Cables?

... and bring it up whenever they start talking about the superiority of one cable over another.

scali: With regard to the analog/digital TV thing, your brother may be confused about analog _broadcast_ TV being shut down in the U.S. in early 2009. There will be no further analog TV broadcast over-the-air, but it will still be available on cable.

https://www.dtv2009.gov/


----------



## Ishan (Aug 26, 2008)

Scali said:


> I think you missed my point.
> My point is that if you add tube distortion to the recording, a SS amp can reproduce that accurately (and various CDs are produced with actual tube distortion or modeled tube distortion).
> Pretty much any 'analog' type of distortion/noise/etc can be recorded and reproduced with an SS amp. Distortion, compression, noise, static, you can add it all if you want. But you also have the option of leaving it out if you want.
> So you can get any tube sound you want out of an SS amp, but you can't get an SS sound out of a tube amp (I could imagine that something like dance/house music won't sound very good on a tube amp at high volumes, because the amp will compress and distort the bass drums and such, losing the punch and tightness that this music is famous for).
> ...



You missed my point too, "hifi" tube amp aren't hifi at all, they do distort the signal far more than a SS stereo, adding even harmonics to the original signal which are pleasing to the ear. Think of it as BBE sonic maximizer but just better  having the purest signal is not everything, trust your ears, no a spec sheet  Some "hifi" tube amp have 5 to 10% distortion which seems overly huge but still, they do sound great 

Dynamic is the ability of the amp to go from very quiet to very loud as fast as possible (that's how I understand it anyway). Not often heard in modern music but very common in classical music, jazz and tones of acoustic genres.

The coat hanger thingy always makes me laugh, and is not much surprising when you see the diameter of those things. If you don't have insanely long speaker cables, almost anything metal with a big enough section will do IMHO.

I remember hearing some recording of the same setup with different speaker 
cables on a german website (can't remember the website) and the lower cable where killing the high end but anything past middle grade cables were sounding the same (or giving a different color to the sound but nothing spectacular). Anything past a Planet Waves is overkill IMO.

Edit: Just to precise my point, I don't believe tubes are the epitome of sound reproduction, I listen to my music on studio monitors which are unforgiving to any bad mix and details, that's the way I like it. Tubes are more if you like an enhanced experience.


----------



## Scali (Aug 26, 2008)

We're in Holland, analog broadcast was taken off the air in 2006 (and we weren't using it anyway, we've had cable for as long as I can remember). He was specifically talking about cable. He's confused alright, but the annoying part is that he insists, even though he has no base for his claims. Then he goes like "Don't you believe me? Do you take me for some kind of idiot?"... Well, he does come off as one this way 

It's unlikely that analog cable TV disappears anytime soon. In some parts in Europe (I think Norway/Sweden) there's over 50% coverage of digital TV now, but in Holland we're only at about 25%, and pretty much at a status-quo. Everyone who wants the benefits of digital TV already has it, the rest doesn't care and is happy with analog (unlike the US, analog PAL TV actually gives pretty decent quality anyway, especially considering that virtually all channels are still SD).
So I wonder if Holland will even make the 2012 goal. The only way would be if cableco's start handing out digital decoders for free, and even then not everyone will want to use a set-top box with two remotes and all that. And there aren't a lot of TVs on the market yet that have digital tuners built-in for the European market, especially not for cable.



Ishan said:


> You missed my point too, "hifi" tube amp aren't hifi at all, they do distort the signal far more than a SS stereo, adding even harmonics to the original signal which are pleasing to the ear.


 
I didn't miss your point, I just said that it isn't how the artist intended, else he would have added those harmonics himself in the original recording.



Ishan said:


> Think of it as BBE sonic maximizer but just better  having the purest signal is not everything, trust your ears, no a spec sheet  Some "hifi" tube amp have 5 to 10% distortion which seems overly huge but still, they do sound great


 
Now you're doing exactly what an audiophile does. You claim that you can hear that it sounds better. Maybe it does, but it's subjective.
As I also said, the distortion a tube amp adds might not be suitable for certain types of music.



Ishan said:


> Dynamic is the ability of the amp to go from very quiet to very loud as fast as possible (that's how I understand it anyway). Not often heard in modern music but very common in classical music, jazz and tones of acoustic genres.


 
In terms of amps, that's called dynamic range. In which case an SS amp generally has a considerably wider range (generally well over 100 db, which is pretty much beyond what the human ear can discern).
In guitar playing, people use the word 'dynamics' to describe the 'richness' of the tone, how it changes from soft picking to hard picking and such, by distorting and compressing it in a certain way, so basically how the amp responds to the player. Ironically it's pretty much the opposite of dynamic range. An amp with a large amount of natural compression will bring out the picking nuances better because they're louder due to compression.

You might mean the same thing with tube 'hifi' amps. Because they sound more compressed, certain details in the music can be heard more clearly.
But again, it's not how the artist intended, otherwise he'd have added compression in the studio.



Ishan said:


> Edit: Just to precise my point, I don't believe tubes are the epitome of sound reproduction, I listen to my music on studio monitors which are unforgiving to any bad mix and details, that's the way I like it. Tubes are more if you like an enhanced experience.


 
Key point being: if you like that.
In my opinion, tubes can add a valuable bit of 'atmosphere' to the music. However, I am of the opinion that the artist should add this in the studio.
A hifi system should only reproduce the music as closely as possible, and not add extra effects. I like to hear the music 'as is', and a well-produced album doesn't need to have extra effects added.

Heck, my brother, even though he thinks he's an audiophile, likes to pour on the reverb and surround effects with his DSP. When I played Steve Stevens' Flamenco A GoGo, you could barely hear the lead guitar. It just literally drowned in all the effects. So I turned off all the effects, and suddenly it sounded MUCH better. His problem is just that he likes to listen to crap music that's all electronic and compressed to hell.
I just play my music on an amp and two speakers, no effects or anything. I just dial out the bass a tad with the eq, because my speakers can get a bit boomy, but that's it.


----------



## Ishan (Aug 26, 2008)

Those discussions are endless it seems  I do find tube amps sound better but that's my ears telling that to me, not some "know-it-all" audiophile or whatever. I don't care for tech specs too much, as long as I like what I'm earing. What's important is what YOU like and not what others like. Don't over think these things too much


----------



## Scali (Aug 27, 2008)

Ishan said:


> Those discussions are endless it seems  I do find tube amps sound better but that's my ears telling that to me, not some "know-it-all" audiophile or whatever. I don't care for tech specs too much, as long as I like what I'm earing. What's important is what YOU like and not what others like. Don't over think these things too much


 
I think the two shouldn't be used together anyway.
What you like is just what you like, and shouldn't be discussed anyway, because it's all subjective. You can tell others what you like, and why you like it, but it ends there, I guess. Nobody else can tell you what you like.

Tech specs however are facts. These can be used in a discussion to get a better insight in what equipment can or cannot do, and how it could or should be used.

It can just lead to strange situations.
For example, an amplifier with better signal-to-noise ratio is said to be a better amp, based on its specs.
However, if someone says "But I prefer an amp that hisses more, becasue the hiss gives me a warm fuzzy feeling", is he wrong?
Therefore I think you shouldn't mix what you like with what is technically the better equipment in the same discussion.


----------

