Optical audio out mostly not working :(

Discussion in 'Apple TV and Home Theater' started by NOD, Sep 16, 2008.

  1. NOD macrumors member

    Jul 20, 2008
    I developed a very odd problem yesterday, after having bought my appletv a few days ago.

    Suddenly, the optical audio out didn't work for almost all of my audio and video files (from various macs).

    When I hook it up via HDMI, everything works perfectly fine.

    I know it's not my toslink cable or other hardware for 2 reasons:

    1) The audio works FINE on the appleTV intro sequence as well as my Handbraked movies. All of my music and TV shows, however, are totally silent, as are the sound effects on menu navigation (this is despite having the sound effects set to 'on.'). Keep in mind that, prior to yesterday, all of these currently-silent files worked fine.

    2) I've changed out the cable 4 times with thoroughly functional toslink cables, and have used the optical ports on my other components without difficulty.

    In terms of why I would need toslink if HDMI works fine -- this appleTV is for a room that has a TV with no HDMI inputs. I have no need for it in my other 3 main rooms, which all have other media servers or HTPC's.

    Has anyone else experienced this? I think I'm gonna end up needing to return this thing. I really didn't want to have to get a 3rd ps3 for media streaming, as it's still a clunky interface with compatibility issues. But this problem is frustrating beyond belief.
  2. Wotan31 macrumors 6502

    Jun 5, 2008
    What's on the receiving end of this toslink signal? It's a great myth that "digital is digital". Toslink devices are in fact not all created equally. Many are very jittery and produce a crappy signal. Some have substandard optics. Many more produce a sloppy square wave that some equipment might have a hard time locking onto. Trust me, you are not the first to experience problems getting two toslink devices to play nice.

    Unfortunately, the only way to find out if two toslink devices are compatible with each other is by trial and error. :(

    Most audiophiles consider the optical toslink to be the "lowest" of the digital interfaces. RCA coax is considered a better interface, and BNC coax better still (because of its true 75 ohm connectors). After that is AES/EBU which does differential signaling for great noise rejection. Beyond that, the "best" digital interface is I2S which splits the data and clock out onto separate wires.

    So yeah, toslink is the low man on the digital interconnect totem pole in terms of quality. :eek:
  3. Tosser macrumors 68030

    Jan 15, 2008
    Not to mention that the cable itself is often made from plastics, not glass.

    Coaxial ftw! (haha, sorry –*I had an urge to pretend to be thirteen)
  4. NOD thread starter macrumors member

    Jul 20, 2008

    It's an Onkyo 805. That's not the problem. And I'm certainly not gonna rely on the aTV's DAC in addition to limiting myself to 2.0 output (yeah, I'm a bit of an audiophile as well -- this is my only room without separates).

    Strangely enough, after probably the 30th attempted reboot of my appletv in the last 2 days, everything suddenly started working again an hour ago.

    Now I have the unenviable task of trying to decide whether or not to return this sucker in the 30-day window on the off chance it's truly a faulty unit.
  5. mcdj macrumors G3


    Jul 10, 2007
    Maybe you had a loose connection, or a faulty cable? If you rebooted by unplugging the ATV, you may have jostled the toslink cable back into position. Wouldn't be the first time.
  6. NOD thread starter macrumors member

    Jul 20, 2008
    Highly unlikely for 2 reasons:

    1) I had already tried FOUR toslink cables (all functional on other units), all with the same results, and let's just say I'm no novice at putting cables in ports. :cool:

    2) Without exception, the only 2 things that worked were the apple tv booting sequence and all of my transcoded movie files (some of which were in mono, some of which were in DD). There would be nothing selectively significant about those 2 things, as opposed to all of my other files.
  7. ascender macrumors 68020

    Dec 8, 2005
    Is there any advantage to using toslink though when your amp supports HDMI?
  8. NOD thread starter macrumors member

    Jul 20, 2008
    The TV I'm using it on has no HDMI inputs (it's the lone non-HDMI remnant in my household, but it's a 300 lb 57-inch TV -- too much of a PITA to get rid of, and it actually has good PQ). Unfortunately, in the age of HDCP, receivers can not take HDMI input and output through component. You need to do HDMI in and out with the receiver.

    Likewise, you can't use the HDMI port for audio only, while using component for video. Receivers aren't set up that way.

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