1 2 Previous Next 18 Replies Latest reply: Jan 31, 2011 8:03 PM by michael_carr
John Etnier Level 2 Level 2 (165 points)
Concerning the optical digital out:

(A) If something's connected to this port, does doing so disable audio through the HDMI output?

(B) Someone in an Apple store said that the optical out is 'only' for 5.1 systems. Is this correct? I wanted to connect it to a stereo D>A converter.

Various
  • 1. Re: Optical audio output questions
    Chenks Level 5 Level 5 (7,420 points)
    John Etnier wrote:
    (A) If something's connected to this port, does doing so disable audio through the HDMI output?


    no

    (B) Someone in an Apple store said that the optical out is 'only' for 5.1 systems. Is this correct? I wanted to connect it to a stereo D>A converter.


    optical carries digital audio (be it stereo or DD depending on the content).
  • 2. Re: Optical audio output questions
    John Etnier Level 2 Level 2 (165 points)
    Thanks.

    Chenks wrote:
    optical carries digital audio (be it stereo or DD depending on the content).


    I don't know what DD stands for in this context. Do you know what a stereo D>A box would do if presented with a 5.1 signal?
  • 3. Re: Optical audio output questions
    Chenks Level 5 Level 5 (7,420 points)
    DD stands for Dolby Digital.
    5.1 is a digital audio format, it is not analogue compatible.
  • 4. Re: Optical audio output questions
    John Etnier Level 2 Level 2 (165 points)
    A D>A converter is a digital-to-analog convertor: it takes in digital signal and converts it to analog.

    My question is whether the DD signal is incomprehensible to a stereo converter, or if they can strip out an appropriate stereo signal from such an input.
  • 5. Re: Optical audio output questions
    Chenks Level 5 Level 5 (7,420 points)
    no idea, but i doubt a digital to analogue convertor would be able to do anything worthwhile to a 5.1 digital feed.

    if the content you are playing is stereo already then the optical cable will be passing a stereo signal to your convertor.

    personally i wouldn't be trying to use any convertor as you end up with an inferior output after conversion.
  • 6. Re: Optical audio output questions
    sevoflurane Level 1 Level 1 (20 points)
    If you disable the option in the audio settings menu to output Dolby Digital, then the optical output will deliver a bog standard PCM output as decoded by a typical stereo component with a D/A converter, irrespective of source material. If this option is enabled, then Dolby Digital material will be output by the ATV via the optical out and will only produce audio if the amplifier has a Dolby Digital decoder. Other material (e.g. audio via Airplay) is still output as a stereo PCM signal. The above setting also affects the HDMI audio output.
  • 7. Re: Optical audio output questions
    John Etnier Level 2 Level 2 (165 points)
    Thank you!
  • 8. Re: Optical audio output questions
    Bo15 Level 1 Level 1 (10 points)
    Hi. I have a similar question. I want to connect my ATV to a Denon AVR-3311 via HDMI and optical cable. Besides the main zone (5.1 DD), I have an outdoors Zone 2 pair of speakers I want to play iTunes songs on; the AVR can't pass a digital signal to Zone 2 unless it's PCM.

    <from the manual> "from an optical connection, playback is only possible if the digital signal being input is in PCM 2-channel format." otherwise an analog connection is required.

    So does ATV pass a PCM signal when playing songs from iTunes via AIrplay to the ATV (then to the AVR)? Will sound come out the speakers in Zone 2 with an optical cable from ATV to the AVR?

    Thanks!
  • 9. Re: Optical audio output questions
    Crudest Level 1 Level 1 (0 points)
    I have the optical cable going into my Denon AVR and it does indeed see it as PCM when playing music from iTunes.
  • 10. Re: Optical audio output questions
    Bo15 Level 1 Level 1 (10 points)
    Thanks. I'm hoping to run the optical input to the AVR (PCM 2.0) audio to Zone 2
  • 11. Re: Optical audio output questions
    workingcars Level 1 Level 1 (35 points)
    If using an optical link, would it not make more sense to take the feed from the tv itself assuming it has an optical output on the tv..?

    Then you only need the 1 optical lead from the tv to the sound processor whatever that may be?

    I looked at all the options available to me on a system involving tv, bluray, dvd, Wii, PS3, and 5.1, and it was the simplest and most rewarding that i could come up with and certainly the simplest...!

    It also has the advantage of being linked to my tv remote for audio though my 5.1 which is Samsung the same as my TV and makes good use of ANYNET so i never forget to turn the audio off..
  • 12. Re: Optical audio output questions
    Lucien Palmer Level 1 Level 1 (0 points)
    sevoflurane wrote:
    If you disable the option in the audio settings menu to output Dolby Digital, then the optical output will deliver a bog standard PCM output as decoded by a typical stereo component with a D/A converter, irrespective of source material. If this option is enabled, then Dolby Digital material will be output by the ATV via the optical out and will only produce audio if the amplifier has a Dolby Digital decoder.


    I assumed this would be true, too. So I connected my ATV to a Vizio Soundbar that only allows stereo digital input with it's to slink connector, and I can't get audio to play through it. I've tried disabling Dolby in the settings. I've also tried different source material, including streaming music to it via both iTunes and airplay.

    I have confirmed that the output works with a Dolby Digital decoder I have in my stereo in the other room. Also, stereo audio plays through the HDMI port when I try connecting to another TV.

    So far, all of my tests imply that the Apple TV can't output stereo digital through the optical port.
  • 13. Re: Optical audio output questions
    Alley_Cat Level 6 Level 6 (17,030 points)
    AppleTV output linear PCM over optical for stereo audio.

    The original was limited to 44.1 kHz 16 bit.

    The new unit apparently outputs 48 kHz 16 bit even from 44.1 kHz material (eg CD rips) which is strange as personally I think upsampling from 44.1 kHz to 48KHz will simply mean the majority of samples are interpolated.

    Is it possible your soundbar does not accept 48 kHz rates?
  • 14. Re: Optical audio output questions
    Lucien Palmer Level 1 Level 1 (0 points)
    Alley_Cat wrote:
    Is it possible your soundbar does not accept 48 kHz rates?


    That was a fantastic suggestion. I hadn't though of checking the sample rate. Unfortunitly that's not the culprit. I just checked Vizio's specs on the VSB200, and it says it supports 44.1k and 48k (and strangely enough, 32k).
    http://www.vizio.com/vsb200.html

    Still, that gives me the idea to hook up my sound bar to the optical out on my RME interface on my MacPro in my studio. I can send it different audio streams that way and test what it can handle.
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