# [SOLVED] iMac Video/Audio Switching and Display Options?



## LoneRider (Feb 9, 2008)

OK, maybe this is something simple but it's bugging me, it's late here (in Iowa) and I just can't seem to figure it out. Earlier tonight I connected my iMac 24 to my HD TV and the digital output (via optical cable) to my stereo system. All was well as I figured out and used the extended desktop on the TV (at 1080p). The audio also sounded great. What I've been looking at since has given rise to 2 questions:

1. How do I get a 2 display system like I have here to use "video mirror" mode so that the display on the TV is simply a reproduction of the one on my monitor? Reading all that I can find in help on this, there seems to be an implication that video mirroring can only be done when 3 displays are involved (I hope that's not true).

2. While I will use the stereo occasionally for the sound output, it will often be turned off or else "doing other things". When the receiver is not available for the Mac's audio I would like to quickly and easily revert to the computer's internal speakers. However, since a headphone jack is involved, the internal speakers are turned off and I don't see any way to revert back except to physically pull that headphone connector out. That's OK (well, sort of) but it's a real pain to get back behind the monitor and reconnect it the next time I want to use the stereo for audio processing. It's also *very* inelegant. Usually when something like this occurs, I figure that I haven't yet come across the information to let me accomplish the task. So am I missing something here? This just doesn't make too much sense to me. Frankly, I was thinking that what I'd get for this functionality is "speaker" outputs that I could switch via software control. What it actually looks like is that there can never be such an option and this scenario will only (really) work properly for those folks that plan to use their stereo receivers for audio all (or almost all) the time.

Any advice or tips on what I can do for either or both of these issues would be greatly appreciated. Thanks!


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## sinclair_tm (Mar 11, 2005)

*Re: iMac Video/Audio Switching and Display Options?*

The video mirror is easy. When the TV is connect to the Mac open the System preferences and click on the Displays button. There should be an arrangement tab that you click on. There will be two blue squares that represent the screens. Drag the one that has a white bar on the top to the other screen and now they will kinda look like there is one on top of the other, and the screens will display the same thing.
As for the sound, there might be a solution 3rd party, but as for the Mac OS, it only sees it as one unit, so it can't use the speakers if headphones are plugged in because there is a switch that the headphones hit to turn the speakers off. You could get an iMic and then you can switch between it and the built-in sound out without doing the plug thing. That is what I do on my Mac at home.


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## LoneRider (Feb 9, 2008)

*Re: iMac Video/Audio Switching and Display Options?*

Thanks for your response. OK, I had already investigated the Arrangement tab under Systems Preferences>Displays, but when I try to move one display icon onto the other (no matter whether or not it is the one with the menu), it simply will *not* allow it. I can move one screen to any of 4 sides of the other but never will it overlay. I can also move the menu so that it's on the TV if I want to. So maybe I'm missing something about video mirror yet, sorry if I'm a bit slow on this.

Thinking the displays issue might have something to do with incompatible display resolutions settings, I've changed the TV from 1920x1080 to as 800x600 and the Mac from 1920x1200 to 800x600 as well but no combination of the 4 sizes makes the video mirroring work.

Regarding the sound, if I use an iMic, I was assuming I would lose the digital sound output (for analog). This I did not want to do (but I wasn't sure if it was going to be true). At any rate, you've confirmed my thoughts the most useful and flexible way of designing a digital video and audio output from the iMac has not been done ... <sigh>.

Any other ideas on the video mirroring would be very much appreciated. I'm just sure that I must be missing some setup thing somewhere but I feel like I've tried them all with no joy.

Thanks!


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## sinclair_tm (Mar 11, 2005)

*Re: iMac Video/Audio Switching and Display Options?*

Loosing the digital out is true, as the iMic is analog. It still sounds good to me, but then I don't have the digital out on my desktop. You could always get desktop speakers to plug into the iMic when you don't want to turn on the stereo, but then that does take up more space.
As for the mirroring, the built-in help says that after you set the displays to the same resolution and color depth that there will now be a mirror displays button under the arrangement tab. Perhaps your color depth isn't the same, make sure they are both set to millions of colors or thousands of colors.


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## LoneRider (Feb 9, 2008)

*Re: iMac Video/Audio Switching and Display Options?*

H-mmm. Thanks for the tip. I played around with setting the resolutions (by moving the menu bar to the TV's display I could set it and that's the part I was missing) and found that if I set the horizontal to 1920 on both, the mirror option was available. Interesting that the vertical resolution is limited to 1080 and that's not a display option on the iMac's 24" monitor, but when I clicked on "Mirror" it shrunk the vertical resolution on the Mac from 1200 to 1080 (I lost some off the top and bottom) and worked perfectly. Frankly, that's just fine and it's the best that can be done given that the TV's vertical resolution is only 1080.

Again, you've confirmed the issue with the digital sound output and I understand your point regarding adding speakers to my desk. Something I don't want to do but I feel pretty strongly that it shouldn't be necessary. Anyway, I consider my question resolved and I appreciate your timely responses.


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## Chris. (Jan 26, 2009)

Lone Rider, I have a question about this, I hope you or anyone else who's done this can help.

With a 24" iMac connected to a 1080p projector (or HDTV in your case) in Mirror mode, you said, _"but when I clicked on "Mirror" it shrunk the vertical resolution on the Mac from 1200 to 1080 (I lost some off the top and bottom) and worked perfectly."_

So do you mean:
a) The image on your iMac now has black bars on the Top and Bottom but shows the entire 1920x1080 image that the TV displays?

or

b) That the image on your iMac is a stretched 1920x1080 image that fills the 1920x1200 resolution of your iMac's monitor, giving the image a small amount of vertical distortion.


P.S. Also are you running to the TV via a VGA or a DVI (HDMI) cable?


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## sinclair_tm (Mar 11, 2005)

You should get black bars on the Mac.


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## LoneRider (Feb 9, 2008)

Chris ... yes, the iMac display matches the TV and has black bars on the top and bottom. I use the DVI connector of the iMac along with a DVI-HDMI converter plug and then a regular HDMI cable over to my stereo's HDMI input. The receiver is connected to the TV via HDMI. When audio from the iMac is needed I connect its optical output to the stereo.


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## Chris. (Jan 26, 2009)

Thanks to both of you for the answer. That's very helpful and exactly what I was hoping for.


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