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One way to 'mirror' DVI displays on a Mac mini Desktop Macs
I am in the process of creating the "ultimate" Mac mini-based home entertainment system. One issue with using a mini is the lack of dual-monitor support, which is a real hassle if the mini is attached to a projector -- turning on the projector to see the screen each time is expensive and time-consuming. Since the mini only has one video output, I came up with a way to effectively mirror the video to both the DVI projector and a DVI-input LCD monitor:
  1. Buy a DVI "splitter" cable (I got mine on ebay). You want a two-female to one-male DVI-D splitter.
  2. Plug the monitor into one fork of the splitter.
  3. Take the cable from the projector, and break off pins 6 and 7 (pinout chart). This will disable the monitor sense function, and the mini won't "know" the projector is connected. Plug it into the other fork of the splitter.
  4. Make sure the LCD monitor's resolution matches the projector's native resolution (you may need to use DisplayConfigX).
Now go watch your DVD. Note that if you don't modify the projector cable, this setup may work when both the LCD and projector are on, but as soon as one is turned off, the mini will blank the video output.

[robg adds: I haven't tested this one...]
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One way to 'mirror' DVI displays on a Mac mini | 11 comments | Create New Account
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Authored by: lullabud on Mar 27, '07 10:04:27AM

For those out there who haven't yet purchased a projector:

Another way to do this is to get a projector that has dual-inputs that can be switched to pass-through. This is what I'm doing with VGA on a Viewsonic PJ656. Video is passed through without needing the projector to be on at all, and that way you can have the same video mirrored on another display other than the projector.

This is also nice because I can point that monitor around the corner into my kitchen so I can still watch video when I get up to mix myself a mixed drink. ;-)

(They censor the word *censored*tail?)

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One way to 'mirror' DVI displays on a Mac mini
Authored by: rspeed on Mar 27, '07 11:01:10AM

Rather than breaking the pins off of the monitor's cable, how about using a short extension?

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One way to 'mirror' DVI displays on a Mac mini
Authored by: Roquentin on Mar 27, '07 01:25:56PM

This is beside the point for those who do want to mirror, but for those who might be thinking about the alternatives, it may be worth pointing out that (1) splitting the signal can affect signal strength and quality, obviously, and (2) there's a pretty good chance that the resolution you'll want to maintain on your mini's computer display won't be the same as the one you'll want (or are able to achieve) on your projector. In my own case, I ended up purchasing a decent A/B video splitter (they're not that expensive) and a BlueTooth keyboard and mouse so that after I make the switch I can do my thing over the projector while I'm sitting on the couch. And because my 1024 x 768 VGA resolution stretches horizontally to fit the 16:9 aspect ratio my projector is configured for, I use the aspect-ratio menu command in VLC media player to display the video in 4:3. That way I don't have to switch my projector to 4:3 (which would mimic my VGA display but reduce the projected display size on the left and right), with the result that the video ultimately displays over the full projection surface rather than a subset of it.

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One way to 'mirror' DVI displays on a Mac mini
Authored by: Roquentin on Mar 27, '07 01:29:27PM

I said "video splitter" but I meant "video switch." Big difference. :)

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One way to 'mirror' DVI displays on a Mac mini
Authored by: beowulff on Mar 27, '07 01:48:49PM

I posted this hint.
One advantage to using DVI-D is that it is *Digital* - so there is no signal or quality loss from splitting the signal (there are limitations to how far the cable can be run). Also, I have found that keeping the mini resolution (1280 x 720) at a multiple of the projector's native resolution (854 x 480) makes for image quality that is better than what I was getting out of my DVI-out Oppo DVD player.
In answer to an earlier post which asked about an extension cable - yes, you could do that, but I found a 15' DVI cable was just as cheap...

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One way to 'mirror' DVI displays on a Mac mini
Authored by: nonno on Mar 27, '07 04:38:02PM

MMM interesting ...

One other option albeit one with cost is to use a Matrox DualHead2Go module. With it you can either mirror or extend your display across 2 monitors. The only limitation is your monitor resolution is limited to 2048x768 (2x1024x768). This limitation is imposed by the limited graphic capability of the Mini.

Personally I prefer extension because it leaves your primary display free for management and other things.

I too want to build the 'ultimate' entertainment server using a Mini, but don't consider it worth the effort until Apple 1) upgrade the processor to C2D and 2) include decent graphic capability.

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ANOTHER way to 'mirror' DVI displays on a Mac mini
Authored by: vonkas on Jun 17, '07 04:23:23PM

Mac mini Intel video circuitry is capable of dual monitor support. You can see this when run under Windows XP/Vista (bootcamp only). It shows the second monitor in the control panel.
It might be worthwhile constructing a split cable where you separate the VGA signal lines from the DVI ones - I wonder if the Mac then thinks or could be coerced to think that it has 2 independent connectors..?

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ANOTHER way to 'mirror' DVI displays on a Mac mini
Authored by: beowulff on Jun 25, '07 03:26:17PM

I tried this.
It doesn't work.
As soon as you plug a DVI monitor in, the VGA output stops. This is probably a software issue, but I don't know what to hack to get it to work.

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ANOTHER way to 'mirror' DVI displays on a Mac mini
Authored by: jhusak on Jan 16, '08 03:55:45PM

I've tried this too with the same effect, but I think the half-solution that switches between two monitors is sufficient, atleast for me.
I keep trying.

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One way to 'mirror' DVI displays on a Mac mini
Authored by: vurey on Jan 30, '09 03:37:53PM

Works great! Thanks for the tip. I wasn't sure how to break off the pins, so I used a very small flat head screwdriver to bend the pins this way and that until they finally broke (taking care not to damage the surrounding pins)

I have my main 32" TV and small 19" TV in the next room both running off the same Mac Mini now. Fantastic!

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One way to 'mirror' DVI displays on a Mac mini
Authored by: Maccrash on Feb 10, '09 02:04:45AM
My question is about the Apple DVI to Video Adapter. I wanted to have TV out on my mac mini for recording quicktime movies to VHS at 640 X 480 resolution and playing video on my TV. I have found a couple of solutions online. The first is getting a DVI Splitter and on the second DVI Port cutting off pins 6 and 7 and then hooking the Apple DVI to Video Adapter to it ( The second was using the Tritton SEE2 Xtreme ( )and connecting the Apple DVI to Video Adapter to that. Both methods are just theory, but I was hoping you guys could shed some light on my situation, or if you happen to know of any other solutions that i can use.

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