Is Optical out better than the S/PDIF out?

I

ImLazZzy

Limp Gawd
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I know this sounds silly but a friend of mine insists that Optical out to a receiver yields better sound than the S/PDIF out. I told him both of them are digital out connectors and all they do is passing over the signals so unless the opical and coaxial cables are of much quality difference, they should really sound the same from the receiver....what do you think? Did anyone compare the two side by side?

Take Audigy2 for instance, the standard Audigy2 only has the S/PDIF out while Audigy2 Pro/Platinum has both Optical and the coaxial. Will outputting the signals from a standard Audigy2 via S/PDIF out to a receiver sound the same as outputting the same source to the same receiver by using the optical out on an Audigy Pro/Platinum?
 
I am certainly not an expert, but in other places (audio forum here, I think) that the coax yields a nominally better sound because there isn't another DAC to go through. Why make another conversion when you don't need to?

Example of coax: sound card to digital DAC (direct to SPDIF coax) to receiver to amp to speakers
Example of optical: sound card to digital DAC to optical DAC (direct to optical cable) to receiver optical in to receiver optical DAC to amp to speakers

Basaically what you are relying on is the optical "ability" to encode and decode information at a quality rate. Sadly, from what I have read, these really aren't present on sound cards and low end receivers.

Optical has its advantages but, from what I have read, sound quality isn't one of them (when compared to coax). Please feel free to refute that or you might check out the Computer Audio forum here.
 
Neither one is really worse than the other.

However as arkamw pointed out in the signal path opitcal has more chances of failure. But for the most part even cheap optical components do a good enough job most people would have a hard time picking out the opitical in an ABX test.

I like coax better simple because the physical connection tends to be better, many optical components connector can be a pain in the butt and the cable pops out.

edit: Oh yes Coax can be interfered with by electrical noise that optical can not, however if your enviroment has so much EMI to cause the resolution of a digital signal to become degraded to the point it can not be read over a distantance of 6 feet, you have bigger issues.
 
No one I know has been able to tell the difference. the differences are all on paper and in benchmarks from what I can tell.
 
arkamw said:
I am certainly not an expert, but in other places (audio forum here, I think) that the coax yields a nominally better sound because there isn't another DAC to go through. Why make another conversion when you don't need to?

Example of coax: sound card to digital DAC (direct to SPDIF coax) to receiver to amp to speakers
Example of optical: sound card to digital DAC to optical DAC (direct to optical cable) to receiver optical in to receiver optical DAC to amp to speakers
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Hmm, interesting....I wasn't aware that you needed another DAC to convert the digital signal from the first DAC to optical. Doesn't make much sense. If you mean a digital to optical converter,...I still don't see how that would make a difference, unless you were using completely crapped out components.

My system was Audigy platinum ex optical out --> sony strde9xx reciever --> speakers, and it sounded great. I only had two floor towers, no surround hooked up, so I was using pcm mode. I was also dealing with the high quality DAC in the sony unit of course.

Note that I would've gone with coax, but when I went to the radshack to get my cable, they had a 10' optical cable for cheaper than the standard coax. but like freud said above, you probably wouldnt be able to tell the difference.
 
mastercheeze said:
but like freud said above
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wow, somebody that doesn;t think my name is a billing for a cage match with a waffle. I am inpressed...
 
I don't see why there would be any digital to analog conversion for optical. I think some people are either misinformed or using the wrong terminology. Fiber optics transmit digital signals. Transmitting a digital signal as light OR electricity is not a digital to analog conversion. The whole thing is digital. They are both totally digital and the quality is exactly the same under usual working circumstances. That's part of the whole point of digital systems.

Now, a valid reason could be that the optical transmitters or receivers suck and drop bits more often than coax, but that's not an inherent problem with optical, it's just crappy equipment and the same thing could theoretically happen with coax, so be careful making overarching statements that one or the other is better.
 
optical is known as S/PDIF too, i just refer to them as optical and coax. As for which one is better, it depends. Its all personal preference
 
Mr. Brownstone said:
I think some people are either misinformed or using the wrong terminology. Fiber optics transmit digital signals. Transmitting a digital signal as light OR electricity is not a digital to analog conversion. The whole thing is digital. They are both totally digital and the quality is exactly the same under usual working circumstances. That's part of the whole point of digital systems.

Now, a valid reason could be that the optical transmitters or receivers suck and drop bits more often than coax, but that's not an inherent problem with optical, it's just crappy equipment and the same thing could theoretically happen with coax, so be careful making overarching statements that one or the other is better.
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I think that you were able to say in your second paragraph what I wanted to say overall. And, yes, my terminology was incorrect. The (albeit small) discussion here seems to hit on all the major points of optical vs. coax and this is a quick FAQ answer on the subject.

Like I said in my very first part of the post, I am not an expert here at all, and, at the end, please feel free to refute what I said. I'll still stand by not having to make more conversions than you need to, but, as has been pointed out, the difference in quality is probably fairly close to negligible. This is all part of the learning process for me.
 
As pointed out many times before digital is digital.

Optical output in the audio world is nothing but a simple light guide setup. You have a LED at the transmitting end, with a phototransistor at the receiving end. The light travels down a simple plastic or glass light guide. (glass does tend to have a higher distance limit, but while being more prone to breakage than plastic. It DOES NOT sound better however, despite what the marketing drones try and make you believe)

The electrical impulses of the digital signal are used to pulse the LED. These pulses are received on the other end by the phototransistor which converts them back to electrical impulses.

With no actual electrical connection the medium itself is immune to EM and RF interference.

There will be absolutely no quality differences between coax or optical. If the signal is not reaching the receiving end intact the result will be ethier audio dropouts and/or pops and clicks. Any defects in the connection will be more appearent when using 5.1 audio due to its higher bandwidth usage.

Bottom line, if you have no drop outs, pops, or clicks, the connection is working perfectly.
 
I also like coax better, because my xbox takes up the only optical input on my reciever :). Maybe i should get a better reciever? Then again, ill wait till i see a nVidia sound storm pciE card come out...damn i want that thing.
 
Optical patches cannot pickup EMI (GOOD) but it is very fragile and therefore isn't good to run under a carpet (near a high-traffic area) and can't make tight radius turns (BAD). Coax on the other hand is the opposite. Due to its copper core it can pick up EMI. Coax is also much more heavy duty and could be stepped on without the patch splintering/breaking.
 
Physical issues with the cabling are about the only valid argument.

Both optical and coax require a DAC on the reception side. Both require a media access protocol to figure out how the bits are dropped onto and read from a physical medium. In all cases results will vary based on the quality of the individual components used in building the hardware.
 
With my Carver m500t amp (lots-of-power) pushing my Klipsch Cornwalls (very efficient) I used to have a very soft hum, that was independant of the pre-amp's volume (meaning it was the same with the volume down low as it was with it turned up high but nothing playing, like in-between songs on a CD).

The hum turned out to be a ground loop between the CD player and the preamp. Going to optical from coax on the digital eliminated it.
 
I dunno, I switched from coax do optic, and the sound became a lot clearer. While it is transfered from sound card to digital DAC to optical DAC, the signal still isn'tdepleted in any way. It's still a digital signal, therefore, there is no signal loss (dedpending on the quality of the product, of course) Optical is better because, while it is transformed more, it's still digital, and also the signal is carried by light so there is not distortion or signal loss, as opposed to coax where there is signal loss through the wiring.
 
lesman said:
I dunno, I switched from coax do optic, and the sound became a lot clearer. ......
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Placebo effect.

Highly doubt it would show up in ABX test.
 
to sum up this discussion....use whatever the hell you want, you wont notice the difference probably...
unless your spreadin EMI everywhere...
 
I'm not just saying that...before there was some audible distortion, when I switched, it was gone.
 
From someone who works in the audio field... (and i'm an engineer, not an audiophile, and i fucking hate audiophiles)

Assuming the receiving end of the SPDIF signal is properly designed, then you shouldn't notice any difference between optical/coaxial. If you do, then chances are your receiving end is crap or you have a terribly bad cable.

There's more to SPDIF than "getting the bits across the wire" - the receiving end of a link also has to recover a clock from the biphase signal using a PLL, and this recovered clock is used to drive DACs and whatnot inside the receving end. If the PLL can't recover a good clock, either because the interface is bad or the PLL itself is shit, then it's possible to get audible jitter.

Some people claim to hear a difference between SPDIF cables. Honestly, I've heard it - and the Audio Precision gear which I use at work (which can measure jitter) agrees with me. Mind you, I was comparing a homemade RG-59 SPDIF cable with a crap dollar store cable.

For the most part, an optical interface has more inherent jitter. But you can make a coaxial cable sound worse simply by not using 75 ohm cable. The reflections that can occur on a cable as a result of this can cause hell with clock recovery circuits if they're not properly designed.

But optical cables have the advantage of electrical isolation. Plugging in a coaxial cable will invariably connect the grounds of the sending and receiving ends, and if they're already grounded together through the wall or something, then you can create a nice ground loop antenna that can potentially pick up all sorts of bad stuff.

My question for the thread starter - what kind of coax cable are you using? if you're using a thin gray cable from radio shack, then toss it and try a good composite video cable. If it doesn't help, then keep the optical side hooked up and play a bit of music, but plug a coaxial cable into your receiving end and touch the shield of the cable against the metal on the back of your computer's case. Does it sound worse?
 
what's wrong with listening to recordings the way they're meant to be heard? You should really listen to some high end hifi..
 
ImLazZzy said:
May I ask why you hate them?
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My day job = engineer at a company that makes broadcast equipment. And i'm responsible for almost all of the audio hardware in the equipment that we make.

And we often sell equipment to audiophiles... most people that run radio stations are people with way too much free time, that earn way too much money, and are surrounded by too much music for their own good. And to make matters worse, they've got enough technical knowledge to be annoying and dangerous. I'm the guy that has to deal with these people, and listen to them insist that we use a certain brand/type of fucking power cable, solder our audio boards and audio connectors with silver solder (just try that with a SMT reflow process), gold plate everything in sight, etc... And every last one of them brags about their audio gear incessantly.

And this is at work. I do audio stuff (amp design, etc) as a hobby, and it's the same thing.
 
tommo said:
what's wrong with listening to recordings the way they're meant to be heard? You should really listen to some high end hifi..
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I own (and build) high end hifi. ;) I'm all for the pursuit of better sounding audio.

But thrusting your own subjective opinions on the rest of the world as if they were fact, in the most disrespectful manner possible, is the basis of being an audiophile. This, I hate.
 
gee said:
My day job = engineer at a company that makes broadcast equipment. And i'm responsible for almost all of the audio hardware in the equipment that we make.

And we often sell equipment to audiophiles... most people that run radio stations are people with way too much free time, that earn way too much money, and are surrounded by too much music for their own good. And to make matters worse, they've got enough technical knowledge to be annoying and dangerous. I'm the guy that has to deal with these people, and listen to them insist that we use a certain brand/type of fucking power cable, solder our audio boards and audio connectors with silver solder (just try that with a SMT reflow process), gold plate everything in sight, etc... And every last one of them brags about their audio gear incessantly.

And this is at work. I do audio stuff (amp design, etc) as a hobby, and it's the same thing.
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Sounds like you have an interesting job, gee. I wish I could put my hands on some really prohibitively expensive stuff. Well, I bet there are still some *audiophiles* who are not as annoying and disrespectful as your customers....
 
ImLazZzy said:
Sounds like you have an interesting job, gee. I wish I could put my hands on some really prohibitively expensive stuff. Well, I bet there are still some *audiophiles* who are not as annoying and disrespectful as your customers....
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I love my job.

And there's plenty of audio enthusiasts that I know; I just don't call them audiophiles.
 
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