What is the difference between coaxial and fiber optic's? Which is better?
Anonymous
Posted on
FIBER in effect transmits in the LIGHT domain whereas coax operates within the realm of electrical signals - which are quite slower. However in practical terms, this is irrelevant for typical home setups
WITHIN THE HOME for regular purposes, e.g. theater/audio setups and wire runs etc - coax will work fine and you really cannot tell any difference in quality.
Of course longer term on the separate issue of transmission INT0 the home from distance sources 1000's of miles away e.g internet access, hi def transmission via cable - ALL OPTICAL (eventually including all optical switching) is where its all headed. LIGHT has near unlimited capacity and unlimited speed. In practical terms, fiber is preferential over cable for the cable choice into the house - due to the massive capacity/speed of light transmissions
As said, sound wise, you won't be able to tell a difference. The only benefit, over a short run, of optical cable is that it is much less suceptible (spelling?) to interference from other electronic devices.
E. Ramsey
Unregistered guest
Posted on
This issue has been debated since 1997 when DVD and its digital outputs came about. An optical(toslink) is immune to electrical interference, but it does have one drawback, it has a more limited bandwidth only 20hz to 20khz, the exact range of normal human hearing. I prefer to make my connections with coaxial digital cable because of it's wider bandwith 5hz to 30khz. Although it is subject to electrical interference, the amount of such is silly, way overrated and vanishingly small. The typical output voltage of a coax digital output jack on a dvd or cd player is only about 1 volt peak to peak. This voltage is far to weak to pose any interference considerations, and to worry about such, especially with a decent, shielded cable like Monster is snake-oil nonsense. E. Ramsey AAS industrial electronics
Thank you! Now I can tell him to shut up and stop bragging. He thinks that his dvd player sounds better because he is using a fiber optic and I'm using coaxial.
Thank you for your information, it is very much appreciated.
Hi all!! I have a problem here to....my sony str-de475 amp has an optical digital in port, where it stands TV/SAT in. Next to it is a coaxial port with the label DVD/LD in. My problem is: in the process of connecting my dvd player to the amp i bought a optical cable after heareing that was the best solution...but after connecting it to the TV/SAT my sub woofer kinda dissapares!!! is that because my optical goes into TV/SAT??? can i use coaxial with the same sourround effect?? please answer, been up 26 hours trying differente settings...ending up pulling my hear out!!!
E. Ramsey, could you please explain the connection between 5Hz-30KHz frequency range and the constant 192KHz/32 bits flowing through an S/PDIF interconnect?
Easy audio cable question for the experts... Do I have to connect both the coaxial cable and composite?(red and white) audio cables for the best sound hookup for my DVD player? Or can I just use the Coaxial Cable? Does it really matter? Just need a little help. Thanks
E. Ramsey
Unregistered guest
Posted on
Actually,I was wrong Arnold L., A coaxial digital actually is capable of a much higher bandwith than 30 Khz. What exactly is a S/pdif interconnect? Are you refering to a coaxial digital or optical when you say S/pdif? Their are no "bits" flowing through a digital cable, be it coax or optical. In the case of a coax digital the signal is sent as a 500mv signal in electrical pulses with two states "on-1" or "off-0". In the case of an optical digital signal it is of course light pulses but the same "on-light pulse=1, "off-no light pulse=0" If you are talking about 192Khz, this is the current maximum sampling frequency of a dvd processor, which has a bit word length of up to 24 bits not 32. Alan D., always use the coax digital,or optical over the red and white (rca analog) because it is impossible to get digital surround with the analog(red,white rca) connector. E. Ramsey AAS industrial electronics
s/pdif = Sony/Philips Digital InterFace, the protocol specs for the coaxial connection commonly used in consumer products. I think for optical we better say "Toslink", being a Toshiba development.
I suppose in the coaxial cable actually the bits are represented as "bumps" on a sine-shaped high frequency voltage curve (please correct me if I'm wrong). Anyway, a maximum of 192.000 x (24 audio + 12 protocol related) = 6.144.000 bits per second should be transfered from player to receiver.
The bandwidth necessary for this is within the digital domain. In the analogue (i.e. audio) domain (after conversion), frequency range is a little less than half of the digital sample rate. For instance, CD sample at 44.1KHz which gives audio at maximum 20KHz. The number of bits in the sample gives the dynamic range, losely speaking the difference between silence and full volume. (These relations do not apply to SACD, 2.8MHz/1 bit but audio still in KHz and a pretty good dynamic range.)
Conclusion: I agree on coaxial being superior, but I think we still have to look for the physical explanation.
Hasta pronto AL
E.Ramsey
Unregistered guest
Posted on
Your commentary seems reasonable A. Layne, I tend to favor coaxial because it has a higher bandwith than the Toslink/optical connector and this may sound subjective but the optical sounds more "compressed". E.Ramsey AAS industrial electronics
My subjective opinion too. A local magazine here claims now and then Toslink having less dynamic range. Which could perfectly be perceived as "compressed". But if transfer protocol meets similar KHz/bits specs, it shouldn't be. Seriously, it's a mystery. Could it be that digital/optical conversion intervenes?
Cheers AL
E. Ramsey
Unregistered guest
Posted on
Possibly there is a time lag diffrential as the light pulses are converted to binary then to analog but I am purely speculating. Another thing I have come across that some posters on this forum have stated that they can use a standard rca cable for a coaxial digital. I haven't tried this but it may well work but BEWARE, A true coaxial digital cable has a solid copper conductor as opposed to a standard (analog) rca which has a stranded conductor. When this standed one is used people may experience sound "dropouts"during dvd playback. In a coaxial digital cable the conductor is solid copper because a 75 Ohm impedence must be maintained or at least very close to this since cables aren't perfect. E. Ramsey AAS industrial electronics
E. Ramsey
Unregistered guest
Posted on
Possibly there is a time lag diffrential as the light pulses are converted to binary then to analog but I am purely speculating. Another thing I have come across that some posters on this forum have stated that they can use a standard rca cable for a coaxial digital. I haven't tried this but it may well work but BEWARE, A true coaxial digital cable has a solid copper conductor as opposed to a standard (analog) rca which has a stranded conductor. When this standed one is used people may experience sound "dropouts"during dvd playback. In a coaxial digital cable the conductor is solid copper because a 75 Ohm impedence must be maintained or at least very close to this since cables aren't perfect. E. Ramsey AAS industrial electronics
Easy audio cable question for the experts... Do I have to connect both the coaxial cable and composite?(red and white) audio cables for the best sound hookup for my DVD player? Or can I just use the Coaxial Cable? Does it really matter? Just need a little help. Thanks
Digital coaxial and Analogue RCA are there as alternative interconnects. So one of them is sufficient. If you use digital interconnect, sound processing is done by A/V receiver. This is often the best solution. But analogue interconnect might be preferable if DVD player's chips are superior to receiver's DSP and DACs.
I've always believed that if you are going to use digital coaxial you may want to buy a good quality cable with some decent shielding on it. With optical you don't need to spend quite as much.
Anonymous
Posted on
There's absolutly (and may I insist on this: _absolutly_) no difference between copper and fibre when transmitting an audio signal over a distance of 10m. No difference, zilch, nada, none. No compression of the resulting signal either, in fact, as compression is the fact to limit the upper values of the analog signal. The only explanation of a sound difference between a copper link and a fiber link is that the two links does not share the same digital->analog converter, thus resulting for the same digital signal into a slightly different analog signal - the dynamic response of a DAC changed from a chip to another.
"There's absolutly (and may I insist on this: _absolutly_) no difference between copper and fibre when transmitting an audio signal over a distance of 10m"
hmmmm this kinda contradicts this:
"The only explanation of a sound difference between a copper link and a fiber link is that the two links does not share the same digital->analog converter, thus resulting for the same digital signal into a slightly different analog signal - the dynamic response of a DAC changed from a chip to another."
strange.
D Singh
Unregistered guest
Posted on
This forum has helped me a bit. I currently have my DVD player (a nice Panasonic with HDMI out with a regular video RCA used for the dig coax connection). I have always had a question about whether it was a good idea and people have said "no" but failed to explain why. E. Ramsey laid it out in simpler terms.
For Alan Davis: with the regular RCA connect you won't get multi-channel sound, only 2-channel sound. If you want true surround sound, go with the single digital coaxial cable.
Optical fibers made of polymer (as used in cheap toslink cables) have a limited bandwidth of around 5-6 MHz. This causes jitter in the clock recovery circuits at the receiving end, which causes inaccurate playback of the audio samples, as well as aliasing effects.
With long fibers, data errors can also be introduced due to attenuation of the optical "signal".
Good quality DACs can largely eliminate the jitter issue nowadays, as can good quality (multi-strand glass) fibers, but there is a hefty price penalty to pay.
Then again, if you use a cheap coaxial cable (standard RCA cable - yuck!) you will have similar jitter issues (due to bandwidth limitations) and you may well get a better result with a cheap toslink cable.
Karsten
Unregistered guest
Posted on
The issue of whether light or copper is "better" depends entirely upon the recievers and output signals. The coaxial method is tried and true. I say this assuming everyone agrees digital is better than analog. I do agree the difference in coaxial and optical depends on the following: the reciever and cd/dvd output, distortion (whereas optical is better), and the length of cable. Its all a relative issue.
Hi E. Ramsey, Can you please recommend some online stores where I can pickup decent quality coaxial digital cable (if possible with pre-fitted RCA connectors). I want to connect my DVD player audio to my A/V receiver. Can I use this same cable (3 of them) as component video cable? Can I also use it to connect my sub-woofer. My budget is limited, but after reading about coaxial cables i feel i should be able to get good quality cables (not top of the line) for a low price. Thanks in advance
Amit: I can only if you live in the U.S.. IF so,your best bet is the internet. Try accessories4less.com or partsexpress.com. Accessories4less carries good quality Acoustic Research (AR) cables which are very comparable to Monster which is a decent but inexpensive cable. Neils: While its true that the bandwith of your basic fiber optic cable used for digital connections for HT will have a bandwith in the MHz range the optical circuitry that operates the Toslink connector is very limited to just the audio bandwith 20Hz-20KHz, this is one reason I prefer coaxial over optical.
Amit: Your welcome. Excellent choice! I have heard of the Blue Jeans cables but never used them. They are a little pricier than the AR or Monster but are a sensible design free of snake oil.