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iMac to AV receiver via DVI-to-HDMI cable

Discussion in 'Apple TV and Home Theater' started by Nothlit, Jul 7, 2013.

  1. macrumors regular

    I recently purchased an AV receiver to augment my home entertainment setup. My iMac (late 2009) is in my living room. For years now (prior to getting the AV receiver) I've had the iMac connected directly to my TV via a mini-DVI-to-DVI adapter connected to a DVI-to-HDMI cable, and this worked great. (Audio was routed separately.) However, when I moved this video connection over to the receiver instead of the TV, I started having problems. The signal passes through just fine and looks great, but whenever I turn the receiver on or off, the screen of my iMac flashes blue for a second, as if the iMac thinks I have physically plugged or unplugged the secondary display. This never happened when it was directly connected to the TV and I turned the TV on or off. It's very annoying and disruptive.

    Is there any way to solve this problem? I thought about putting an HDMI repeater in the path. Maybe if the iMac sees an "always-on" device like a repeater, it won't do the blue flash thing when I turn the receiver on or off? Haven't tried that yet.

    For the time being, I have just gone back to connecting the iMac's video output directly to the TV and only routing the audio through the receiver, but ideally I would like to have both the video and the audio going through the receiver just to simplify things.
  2. macrumors 68000

    Does DVI carry the audio? Guess with DVI you need a separate cable for audio anyway, so I won't bother running the iMac to the TV directly.
  3. macrumors regular

    No, DVI does not carry the audio, but I am not concerned about that at all. My issue is regarding the way the iMac responds to having the video signal routed through the AV receiver vs. directly to the TV.
  4. macrumors 603

    Actually the DVI spec doesn't support audio but DVI does carry audio. Audio is in the video stream located in the "blanking" area between frames.
  5. JAT
    macrumors 603

    It really depends on what precisely you and all your components are doing. When you "shut off" the 2nd monitor, the Mac has to resync video. You have to avoid that with different usage, you can't change the functionality.

    My experience using a Monoprice HDMI switch suggests you could get away with putting one of these in between the iMac and receiver and get what you want. I'm betting the 3x1 $25 switch would do what you want, my older 4x1 does it. Not sure if the lower end, not "Enhanced" models would, though.

    Although, I use my TV as a 2nd monitor, not mirrored. And that means the Mac thinks it is still there and you can move your cursor over to the 2nd monitor space even when that monitor is off, losing it for a bit. Worse, you can get some programs that open windows in the 2nd monitor, and you can't access them very easily blind.
  6. macrumors regular

    What you describe at the end there is how my setup has worked for years with the iMac hooked up directly to my TV. It was only when I started routing the video through the AV receiver instead of direct to the TV that this issue began. It's good to hear that you think an HDMI switch might be enough to convince the computer that the monitor is still present. Do you think an HDMI repeater would do the same, or would a full-blown switch be necessary?
  7. macrumors regular


    What is the model of receiver you are using? Some receivers offer HDMI pass-through and auto-switching so that even when it is off, the active signal will still get routed to the TV. I don't know if that will solve your problem of the screen flashing but it would be something you could try without buying another device to put in the chain.
  8. JAT
    macrumors 603

    It seems like a repeater wouldn't be enough because I doubt it does an EDID handshake. But I don't actually know for certain.
  9. macrumors newbie

    yeah,you could try without buying another device to put in the chain. thanks[​IMG]

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