Is there a difference in sound quality in connection 6ch direct (analog) vs Optical (digital)?

Discussion in 'Computer Audio' started by Ladic, Nov 8, 2017.

  1. Ladic

    Ladic [H]ard|Gawd

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    I have Soundblaster Z and Logitech z906 speakers. I use the 6 ch direct method, 3 aux cables to the sound card to #1 input (3aux cable in) on the Z906 speakers.
    I know that 6ch direct way lets the sound card do the work and if I use the optical then the speakers will do the work.
    However for gaming/music, etc, is there really a difference in audio quality of one over the other?
    I always had the impression that Optical (digital) should be better?
     
  2. Vader1975

    Vader1975 Limp Gawd

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    These things are subjective.Your original method is analog and that sound is typically considered to be warmer. Optical is a digital recreation that is sharp but sometimes is incorrectly designed and chops off highs and lows like Vinyl vs CD. So it depends on the source and the range of the digital signal. If it meets or exceeds the source then it will be very clear and nearly indistinguishable from the analog..
     
  3. capt_cope

    capt_cope Limp Gawd

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    A digital signal is either perfect or not working. It doesn't clip. It isn't "sharper". Early CDs sounded like crap because of mastering, not the format.

    There's a decent chance your Soundblaster Z has a better DAC than the speakers, so sending a digital signal to the speakers might sound worse. That and I'm not sure how many channels optical connections support (I've only ever used it for stereo sources). But it doesn't cost anything to hook it up both ways, I'd try it out and see if you notice any differences.
     
  4. Vader1975

    Vader1975 Limp Gawd

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    I see you know very little about how CD's were made and what they did with the digital signal sources. Good try though. I said incorrectly designed. Then you wrote out what that design was Incorrectly mastered for the digital format. I have listened to DAC's that make the music sound sharper and cut off the highs and lows with the source signal being excellent. Not everything is as cut and dry as you seem to like. Which is why I also suggested he attempt it and I mentioned the quality of the source material being key to the digital output. Are you confused as to what that meant?
     
  5. Meeho

    Meeho 2[H]4U

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    What are you on about?

    Your SoundBlaster has much better components than the Logitech speakers. If there is a difference, the analog out from SB would probably be the one sounding better. Plus, you'll be able to use its various processing options, especially for games.
     
  6. HammerSandwich

    HammerSandwich Gawd

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    Because Toslink was designed for 2 channels, it supports uncompressed PCM (up to 24/96) for stereo. To put 6 channels in the same bandwidth, Dolby & DTS use lossy compression. Will this make an audible difference? That's basically the same as asking if MP3 coding is audible. IMO, the chances are fairly small (especially with computer speakers), and the differences would be minor as well.

    If you experience issues with hum & noise, the optical connection could help.

    But Toslink cables are dirt cheap. Try it for yourself.
     
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  7. Stanley Pain

    Stanley Pain 2[H]4U

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    Those would be faulty/shitty DACs then.
     
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  8. djoye

    djoye 2[H]4U

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    If you're gaming, stick with analog, there will be significantly less compatibility issues. If you want to listen to bit-perfect 44.1 or 48 kHz stereo music, go with SPDIF.
     
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  9. pippenainteasy

    pippenainteasy Limp Gawd

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    Optical won't pick up electrical noise from the PSU or EMI generated by the PC.
     
  10. B00nie

    B00nie [H]ardness Supreme

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    I see you know very little about how computers process audio. By definition you can not get analog sound out of your computer. The 'analog' outputs of the soundblaster differ from the external DAC only by the fact that it's been DA converted inside the soundblaster instead of an external DAC.

    A 20 dollar(ish) Soundblaster may not have as good quality components as a 200 dollar dedicated DAC and there the differences may occur. Also whenever you connect a computer galvanically to an amplifier or external DAC, ground loop problems and voltage leak (from PSU) problems _will_ occur.

    So if anyone imagines that the analog out would sonically be any different to an external dac (by definition) is sorely mistaken. That does leave room for differences between the qualities of the DAC though.

    The galvanic problems I mentioned are far bigger a problem than the quality of the DAC usually so for that reason alone I would use an optical connection and an external DAC for any serious listening.
     
    Last edited: Nov 9, 2017
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  11. Stanley Pain

    Stanley Pain 2[H]4U

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    This.

    Unless you have a Xonar Essence STX or similar type of card that has REALLY good analog outs on their own dedicated circuitry I wouldn't bother with analog out.
     
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  12. westrock2000

    westrock2000 [H]ardForum Junkie

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    By using optical/coax, it's giving the processing of the surround sound to Logitech z906 speakers. By using RCA cables, you are putting the processing the in the sound card.

    Theoretically, the analogue output is more future proof at the amplification side, because it doesn't matter what codec is used, only that it can reproduce the analogue signal. So someday when Dolby 9000 128bit Colossal format comes out, your Logitech speakers will still be ok if something else can decode it.

    There are also static and ground loop concerns with analog cables, but no one can predict if it will happen. Just have to try and see. (and don't think that optical will mean zero static.....static comes from all steps of the chain).
     
  13. MGV001

    MGV001 n00bie

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    My $0.02: I am a regular reasonably tech savy person, but no audiophile by any stretch of the imagination. This thread caught my attention because I have a very similar setup. I am using an onboard Realtek audio on an ASUS ROG Maximus Ranger VIII board. It has both analog and digital optical out. I have the Logitech Z906 system as well (picked it up recently when my 10 year old creative labs 5.1 gave up the ghost and Amazon had a flash sale on the Z906).

    I have both the analog and optical connected to the Z906 and have painfully pissed off my wife by constantly switching between the two while performing various audio related tasks (Netflix, Youtube, Megadeth....).

    Bottom line: There is an audible difference, but for the life of me, I can't decide which is better. The difference is there, but it is not distinct enough in either "camp" to provide, at least to me, a clear winner.

    As a poster mentioned above, the optical does run into compatibility problems here and there. For example, I cannot get Witcher 3 to run 5.1 on the optical, but it runs 5.1 just fine over the analog. I have researched some "workarounds" by altering DLLs in this folder or that folder, but frankly, it is not worth tinkering since the analog 5.1 works.

    The board uses an ESS ES9023P DAC, but honestly, I wouldn't know the difference between a good and bad DAC from model numbers and specifications alone. I have no idea if the onboard DAC is any better or worse than the DAC in the Z906.

    At the end of the day, you can pick up a TOSLINK cable for next to nothing and have both and play with it to your liking. The Realtek Audio Manager has equalizer adjustments for both analog and digital outputs and by tinkering with those settings, I have obtained a sound quality that I am happy with. I can only presume your SoundBlaster Z has many more software settings.
     
  14. djoye

    djoye 2[H]4U

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    To get 5.1 through optical/coax with games, your sound device needs to support Dolby or DTS real-time encoding so that it can encode the game's 5.1 output into a compressed data stream that can be sent over the SPDIF cable and then decoded as Dolby/DTS on the receiver or Z906. This feature is supported by some PC audio devices, but it's not terribly common to find that functionality with onboard audio. I wouldn't call myself an audiophile, but game audio isn't typically lossless (it's already compressed one way or another), so I don't like the idea of having it then run through a Dolby/DTS codec; when you run with analog connections, you get the audio as-is without any additional unnecessary processing.
     
  15. Stanley Pain

    Stanley Pain 2[H]4U

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    If heard some audiophiles argue that EM could affect the sound in an optical connection. I didn't have a big enough image of a roll eyes for that one :D
     
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  16. MGV001

    MGV001 n00bie

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    Pardon my ignorance here, as I am not an expert on this issue, and I appreciate your response. Isn't that what DTS Connect and/or Dolby Digital Live are supposed to do? Real time encoding into a digital signal that can then be decoded by the Z906? The Realtek chip has DTS Connect (or at least did have that functionality until the latest Windows 10 updates).

    And don't get me wrong, I am not suggesting that the Dolby Digital or DTS for Witcher 3 would be any better, just that I could not get it to work so that I could, at least, make the comparison.
     
  17. djoye

    djoye 2[H]4U

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    Heh, no problem. Yes, DTS Connect is supposed to do just that. Because you were able to get it working over analog, it sounds like your speakers are configured correctly, so Witcher 3 must have a problem detecting the speaker config when DTS Connect is active, Witcher then defaults to stereo. If you wanted to look into it, I'd confirm that your speaker config in Windows playback devices is still configured to 5.1 after enabling DTS Connect.
     
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  18. MGV001

    MGV001 n00bie

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    Thanks for the reply. There seems to be an ongoing issue right now with the ASUS ROG line and the Realtek audio with respect to DTS Connect and Windows 10. ASUS has yet to offer a solution and I have read on the ROG boards some of the posts where buyers are mad because the latest audio drivers from Realtek (available on ASUS' site) do not support DTS Connect after a certain Windows 10 build. In fact, when I load the Realtek Audio Manager and click on the DTS tab, there is a text box that says something like "DTS Connect not supported after build ....."

    Now, when I use the Windows 10 playback device settings, I can enable the digital out, but cannot select anything other than 2 channel stereo playback. Funny thing, though, is that under the same settings, I can test both Dolby and DTS and Windows 10 will play the test tones for all 5 speakers and the sub.

    To confuse matters even further, when I use the Windows 10 Netflix app, I seem to be getting surround sound of some kind. My Z906 "Decode" light comes on and the Logitech system can decode DTS and DD. When playing YouTube videos, the 2.1 light comes on. All of this is using the optical in to the Logitech system.

    My point to this, and I do apologize for rambling, is that after Build 1703 that was released earlier this year for Windows 10, the Realtek driver for DTS Connect seems to be having issues and there really is no way for me to select DTS Connect any longer in the Windows Playback Devices settings for the digital output - yet, the Logitech is decoding something when it receives a compressed 5.1 signal of some kind. So, perhaps the optical is passing through DTS or DD, but the Realtek cannot do "realtime" encoding for non-DTS or non-DD signals?
     
  19. Pandur

    Pandur Limp Gawd

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    If you play existing DTS/DD content your Realtek can bitstream this compressed audio without fiddling any more with it. Which is why you see the decode light while watching Netflix. Then when you watch "regular" audio from Youtube (and other sources) you only get 2 channels because your computer no longer have the ability to encode uncompressed audio and spdif can only handle 2 channels uncompressed. Your Logitech calls this 2.1 since the .1 sub signal is taken from the main stereo channels.
     
  20. pendragon1

    pendragon1 [H]ardness Supreme

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    this has been an issue since 2015. its something to do with the dolby licensing in windows 10. there were hacked drivers but they stopped working early this year. check this thread, see if anyones made headway: https://www.techpowerup.com/forums/...ital-live-and-dts-interactive.193148/page-104
     
  21. Stanley Pain

    Stanley Pain 2[H]4U

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    Alternatively if you have a good AVR, just run audio out from your Video Card's HDMI to your AVR.
     
  22. Audiochris

    Audiochris [H]ard|Gawd

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    It wouldn't affect the signal while being transported through the optical cable but EMI could definately affect the components on either side of it.