Digital Audio: TosLink vs Coaxial

Discussion in 'Macintosh Computers' started by Grimace, Dec 3, 2003.

  1. Grimace macrumors 68040

    Grimace

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    #1
    What's the best way to hear multichannel sound? I've heard arguments on both sides of these two formats. Has anyone seen any definitive research on which one sounds better?
     
  2. SilentPanda Moderator emeritus

    SilentPanda

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    #2
    Like you said... it's been argued both ways... I myself use an optical cable just because it feels cooler to me... as far as quality of sound... just buy both cables, try it out and return whichever cable doesn't do the trick for you...
     
  3. bousozoku Moderator emeritus

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    #3
    I went for TosLink. After using fibre optics for networks, it just makes more sense to me. With a properly covered cable, there is no way for outside influences to affect the transmission.

    With any metallic wire, it's just the opposite. No matter how well shielded the coax is, electrical fields are all around it.
     
  4. Grimace thread starter macrumors 68040

    Grimace

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    #4
    my issue is that I received a DVD player from an online retailer - and it was the wrong one and only has an optical connector. The one I wanted had both. (The price difference was negligable - but they charge a 5% restocking fee and I have to pay the return shipping, even though they screwed up.)

    I basically want to know whether I'm going to get the same sound from the Coaxial - I was happy with my old TosLink player until I dropped it...
     
  5. WinterMute Moderator emeritus

    WinterMute

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    #5
    The linkage should make very little difference in a domestic system, remember that you are listening to the D-A converters in the amp, not the signal down the cable, which is binary code basically.

    Cables make a difference in analog systems, as the signal carried in the cable is directly responsible for the audio output from the amp and thence the speakers.

    Having said that, the less interference in a system, the less work the error correction has to do and the easier it is for the D-A to re-constitute the waveform.

    I think opital is pretty cool too...:D

    Pro digital formats have electrically balance connections, but I don't think coax does.
     
  6. cpjakes macrumors 6502

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    #6
    Either or....

    WinterMute makes a good point about where the digital cable (TosLink or coaxial) is in the signal chain. The binary coding of the bitstream in any format has built-in error correction, so even if it's strewn among many other cables, a coaxial cable will probably be fine with mild amounts of interference. I have used both and like both equally. Coaxial cables are cheaper to come by (or make, if you're into that). But TosLink does look cooler. It's also easier to tell your ins and outs without a lot of light. Plus they serve as little flashlights if you need them behind a lot of gear. :)
     
  7. krimson macrumors 65816

    krimson

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    #7
    Wow.. i was looking for this same info/opinions earlier this morning.. took alot longer than clicking on this thread and reading the info here.. :D

    Thanks guys.

    im going Tos over the Coax after i get outta work.
     
  8. TommyC macrumors newbie

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    #8
    First of all you should be able to return the player if it's any real concern. IANAL but I would think that the company who sent you the wrong item would be required to pay for return shipping and not be allowed to charge you a restocking fee. After all it's their mistake, not yours. Talk to them and explain the situation and suggest that you'll take more extreme measures if they are not willing to fix the problem they caused. By "more extreme measures" I mean calling the Better Business Bureau, Disputing the charge with the CC company and/or file a claim in small claims court. If it wasnt the one you ordered then I would think that they are in violation of the sales contract they made with you. Hopefully you printed out the online receipt. Sorry if this seems like an overreaction to a minor problem but I spent the better part of a summer trying to return an order of computer parts that had been double shipped (and double billed) to me. So I am sick and tired of online retailer's sloppy business practices and hiding behind their restocking fee/no return policies. (Oh and since the package was signed for, VISA said that I had accepted it and they couldnt help me - what BS)

    As for the wire, I use both and havent really noticed a difference in sound quality. Then again I dont use a high-end receiver or speakers. One thing you should think of is the input availability on your stereo. Ive got one coax and two optical so I had to make sure my devices could fit. For the record I use coax for my dvd player (xbox/ps2 use optical) and I havent had any issues. Plus if a coax cable goes Its more likely that I'll have a spare kicking around.
     
  9. Kid Red macrumors 65816

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    #9
    Sound is nearly identical on both. The use is to use coax for short runs, because the toslink can break easily coiled up behind your system rack. Also, coax will degrade the signal slightly over long runs, 25' +) whereas toslink won't degrade over any length.

    So coax for short runs, use toslink if you have units across the run and running wire thru the walls/attic for long runs.
     
  10. ksz macrumors 68000

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    #10
    In the audiophile world, coax cable is widely considered to be superior to TOSLink. With very revealing components, TOSLink sounds brighter and less accurate. Bits are bits, but there are audible differences. The same is true with digital transports whose sole purpose is to read the digital bitstream from a disc and transfer the bits to an outboard DAC. Keeping the DAC and cables the same and switching only the transports, there are still audible differences. Go figure.

    High-end audio manufacturers go to great lengths to isolate different functional subsections from EM and RF interference. Power supplies are shielded from digital sections which are themselves shielded from analog sections. Inside a computer, the audio circuitry is awash in EM/RF emissions and there's no real audible difference between different connector types. If you're an audio purist, you wouldn't be using a computer for critical listening anyway.
     
  11. Grimace thread starter macrumors 68040

    Grimace

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    #11
    Thanks for all of your responses. Here is a small tangent -

    What do people think Apple's rationale is for putting TosLink audio ins and outs on the new G5s?
     
  12. Grimace thread starter macrumors 68040

    Grimace

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    #12
    I thought Apple would put only top-notch components in the G5s, which makes me think that the TOSlink is somehow superior.
     
  13. legion macrumors 6502a

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    #13
    Coaxial is superior. It's a bit of a long explaination, but you can search EE pages or audiophile pages for detailed info. (this has been researched to death, honestly)

    Apple put TosLink because it is more common in consumer devices, thereby allowing easy connectivity for Mac users.

    Pro-audio would use adat or aes/ebu verses spdif (which is what coaxial and toslink connections are for.)
     
  14. ksz macrumors 68000

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    #14
    The crux of the problem is a phenomenon called jitter which refers to small timing errors that can be introduced as the digital bitstream is read off the disc and transported through various processing stages on both the source component and the receiving component. The word clock that cranks out bits in quick succession as tiny electrical pulses can drift by several tens or hundreds of picoseconds between clock periods. The explanation is more complicated than this, but the result is that jitter produces undesirable audible effects. Jitter cannot be completely eliminated, but it can be significantly reduced. Apparently, coaxial connections offer more flexibility in controlling jitter.

    In addition to coax and TOSLink, there are some proprietary interconnect formats such as Laser Linque (aka Single Mode) that is a more advanced version of TOSLink (i.e. less jitter). I think it's the comparatively larger diameter of TOSLink that reduces the ability to control jitter. Laser Linque specifies a significantly smaller diameter along with other enhancements.

    Robert Harley, formerly of Stereophile magazine, has written a detailed explanation here (I haven't read it all..yet):

    http://www.stereophile.com/reference/368/index.html

    The first two paragraphs:

    "Not that long ago, digital audio was considered perfect if all the bits could be stored and retrieved without data errors. If the data coming off the disc were the same as what went on the disc, how could there be a sound-quality difference with the same digital/analog converter? This "bits is bits" mentality scoffs at sonic differences between CD transports, digital interfaces, and CD tweaks. Because none of these products or devices affects the pattern of ones and zeros recovered from the disc, any differences must be purely in the listener's imagination. After all, they argued, a copy of a computer program runs just as well as the original.

    As our knowledge of digital audio has become more sophisticated, however, we've learned that the timing of those ones and zeros is of utmost importance. It isn't enough to get the bits right; those bits have to be converted back into music with the same timing reference as when the music was first digitized. It turns out that timing errors in the picosecond (ps) range—the time it takes light to travel inches—can audibly degrade digitally reproduced music. These timing errors—called jitter—are only now beginning to be understood (footnote 1)."
     
  15. WinterMute Moderator emeritus

    WinterMute

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    #15
    All of the above is basically correct, but jitter won't make the tiniest difference unless you have pro-grade monitoring and the ears to hear the problem.

    Pro-audio bangs on about jitter and bit-rot and all kinds of digital horrors, and some of us can actually hear these problems, but most coonsumers have average sound sytems and have them wrongly placed, and wouldn't know a phase error if it slapped them.;) :p

    For general use, Apples digital links are fine, sure AES/EBU is a better interface, but when listening to AC3 encoded audio off a DVD into a domestic 5.1 system, its hardly a mix-critical senario...
     
  16. Grimace thread starter macrumors 68040

    Grimace

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    #16
    I've been a professional musician all my life so I definitely do hear the smallest details of sound reproduction. I'm using JBL Studio Series speakers - fairly high in the consumer grade market, but not Studio Monitors.
     
  17. ksz macrumors 68000

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    #17
    If the music you hear sounds bright or exhibits other audible effects compared with a CD transport or any other reference system you might have (I have connected several transports to my Theta ProBasic IIIa DAC and readily noticed audible differences), consider adding a standalone de-jitter device (Theta Digital or Monarch Audio among others) and listening for any improvement. De-jitter devices lock onto the incoming bitstream in all the usual ways (PLL circuits), but construct a new bitstream that is re-clocked using very accurate crystal oscillators and other components. De-jitter devices cost about $250 and are easily inserted between the source and receiving components. On the other hand, many mid- to high-end DACs today have built-in de-jitter capability.

    Audio compression standards like AAC, MP3, WMA, etc. are all based on psychoacoustic studies which show that various frequencies, combinations of frequencies, and particular transitions are more or less inaudible to humans. As a result, those bits are thrown out. But on playback, even lossy/compressed formats can suffer from the effects of jitter; jitter is a general problem that affects transfer and processing of a bitstream - any bitstream. If, as a pro musician, you are often required to deal with lossy formats, de-jittering might prevent the music from sounding any worse.

    Summary: (1) compare playback against a reference transport, (2) if the computer-originated bitstream sounds worse [worse is subjective, but you'll know if it does], try a de-jitter device with option to return it. Some high-end PCI audio boards might advertise low jitter and that's another option.

    Of course, for most consumers this is overkill, but if your standard (and requirement) for sound quality is rather high, this might be worth pursuing.
     
  18. WinterMute Moderator emeritus

    WinterMute

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    #18
    Good advice from ksz there, although I have to say that if you are listening to anything short of .aiff files or red-book CD, and that includes everything up to Ogg Vorbis, then the jitter problem is the least of your worries.

    The lossy codecs sound pretty dire in the scheme of things, and the speakers you are talking about will reveal their shortcomings in great detail, carletonmusic.

    I use AAC in my iPod, but the earbuds don't have the detail to show up the artifacts, especially on a train...:D

    Stick AAC through a pair of Dynaudio M2's with a chameleon amp, and it all grinds to a rather shabby halt.

    Mind, I think 16-bit aiff sucks the big one, and I'm only really happy with .5" 30ips analog tape, or 192Khz, 24-bit at a push.

    What an audio snob I am;) ;) :p
     
  19. Grimace thread starter macrumors 68040

    Grimace

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    #19
    So what about the "quality" of the Digital Coaxial Cable or TosLink cable. Is the Monster cable that's thick and pretty going to make that much of a difference if the source material is digital?
     
  20. legion macrumors 6502a

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    #20
    Yes and no... good quality cables with firm end connectors are important, but don't get crazy on spending there (cables can get really, really expensive (>$1K)if you want them to, but the quality would only be important if you have a serious listening room that isolates all other sounds and extremely high-end sound sources; G5s don't count :) )

    The most important thing is to minimize the length of the cable. Shorter is better! If you have to run longer lengths, then a larger gauge cable is better, but in the long run it won't make up for excessive length (pun intended.)
     
  21. Kwyjibo macrumors 68040

    Kwyjibo

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    #21
    this is going to sound really strange, but i've had some experiences with both in terms of use. for the most part i experienced the same quality on my hometheater, the problems I had were that when i was adding components and buidlign the system i had my dvd player with toslink, and then I added a directv receiver with a TOS out... i had a 6ft cable to reach the dtv and it would pop out quite offten or a nudge of the receiver would sometimes pull the cable out. So i tried a coax for the dvd player and the problem stopped because the cable was more secure and less fragile, if the toslink goes out of alignment you need to re-position it. Keep that in mind if your going to be moving stuff once in a while or you think you'll add another device that might have only one port.
     

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