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MIKEinMICH Level 1 Level 1 (0 points)

I have a studio set-up where I need to be able to run two video monitors off of a Mac Mini DVI port.

One display must be at the desk where the Mini is, the second must run into a recording booth for

talent to view the same screen.  This is a 1.83ghz. Core2Duo...2008'ish vintage.. with the


Is there a specific device anyone can recommend - to either allow a split feed to both monitors at

once - or the ability to routinely switch the video display to feed either one or the other monitor?


I'm looking for a very cost efficient way to do this - i see passive splitters but i am guessing that

a cable-only approach isn't going to work and there needs to be some splitter or switcher hardware

box to make this work right.  Thanks for any suggestions,


Mac mini, Mac OS X (10.5.8)
  • Euchre Level 4 Level 4 (1,275 points)

    I take it the displays you intend to use are both DVI only?

    You are right that digital display connections don't usually like to be passively 'split'. Since computers usually use an active two way connection to their displays, this can confuse things. Are the two displays identical?

  • MIKEinMICH Level 1 Level 1 (0 points)

    Hi, I have to double check - not there right now but one is definitely DVI, the other may be VGA as its a little older...  they're not identical - but i would maybe just buy a second DVI monitor to use for this - i am also

    assuming that i wouldn't be able to adapt a VGA to DVI connector - it would still read as an analog signal no?

  • Euchre Level 4 Level 4 (1,275 points)

    DVI as a standard can deliver digital or analog signals, but you can't 'split' one signal that's being sent into one analog, one digital. If the displays were identical, you might be able to get away with using a passive splitter to mirror the same desktop to both displays. The only issue then is HDCP authentication. That might not be necessary and might not come into play though. If your mini really is a 1.83 ghz Core 2 Duo, you should have a full sized DVI port. Those minis came with a DVI to VGA adapter. VGA is analog only. If you did use VGA, you could much more easily just split the output to mirror to two displays, as an analog signal doesn't have the same authentication issues. You would need both displays to support the same resolution and timing frequency. If both of your displays support VGA, this is probably your best way to go.

  • MIKEinMICH Level 1 Level 1 (0 points)

    Hi, thanks for your input!  Yes, it's a 1.83G Intel Core 2 Duo and in fact i am using the VGA adapter for the current Acer S201HL LED monitor...and did the same with the monitor I replaced - a Samsung Syncmaster 710n. Both have VGA support so maybe i've gotten lucky with this combination and can get by putting these two together on a splitter. This, then could in fact be a passive cable-only solution i gather.

  • Euchre Level 4 Level 4 (1,275 points)

    If you use VGA input, yes - you should only need a passive one. Just remember they are going to be getting the same exact image to both screens, and the resolution should be set to one compatible for BOTH screens.

  • MIKEinMICH Level 1 Level 1 (0 points)

    Hi, just got my passive splitter and gave this a try...well, after connection of an Acer S201HL, and SyncMaster 710N, the initial response from the Mac Mini was an error/restart dialog box.  On Restart, the "remote" monitor- the smaller width/older 710n monitor was displaying - acting as the "master" of the two...but Acer was blank.


    I pulled the cable on the Syncmaster and just left the Acer cabled and restarted, then added the Syncmaster, and got dual display.  But, no resolution on the widescreen Acer would allow for anything but a compressed view on the Samsung monitor...  1360X768 and 60.0 Refresh Rate was the only setting to get full-screen view on both.


    I also had a noticeable dimming of both displays - especially the LED "Acer" - with both monitors connected...


    So it works...sort of.  I am thinking....if I get an identical 2nd Monitor, like another Acer S201HL -- theoretically anyway, that would probably work better (?)  I didn't think about the difference in screen size but am guessing that is the main culprit -  The Samsung is a 17" LCD while the Acer is a 20", LED.


    So far if the smaller-screen 710N is the "master" display - there's no resolution setting i've been able to find that will appear without a diminished viewing area on the larger Acer. 


    Before I drop a dime on another monitor, just wondered if you could think of anything else i might for this...


    Thanks again!



  • Euchre Level 4 Level 4 (1,275 points)

    According to the specs, the Acer's native resolution (and hence maximum) is 1600x900. The Samsung's is 1280x1024. The first is an aspect ratio of 16:9, the second is nominally (although technically smaller than) an aspect ratio of 4:3. This means the resolutions are not going to match right and even if one or the other has a way to cope with an incorrect ratio signal, its not going to look right on one of them. Doing a passive split like you are, I'm not surprised you are having such results then. It will be easier if you get another monitor that has the same aspect ratio, and shares at least one common resolution at or below the maximum of the higher resolution monitor.

  • MIKEinMICH Level 1 Level 1 (0 points)

    Hi, this is an update/reply to this older thread because i just got round to setting up two identical Acer monitors using the passive dual-VGA splitter idea you mention -  Well it works but there is a rather significant dimming of

    the display and i wonder if there's any solution to avoid this - like, maybe a sequence/order of startup that would keep both monitors at the same brightness - it seems to only affect one or the other - in this case when i 'added' the 2nd monitor by just plugging in/powering up AFTER starting up with a single monitor attatched to the splitter it only caused the monitor already powered on to dim.  I can adjust it back up manually to a higher brightness but not by much. 


    Any other ideas on a better trick to make this work?  I realize it's largely dependent on what kind of graphics capability the host computer is that you're working with in the first place.  Just kinda wondering if anyone's had

    success getting two displays to maintain identical characteristics using a passive splitter like this - or is there a

    need to somehow 'amplify' with external device of some kind?


    Thanks much!



  • John Lockwood Level 5 Level 5 (6,445 points)

    The following are powered devices and I get the impression (although they do not explicitely say so) that they could be considered 'active' devices.

  (1 source to 2 output VGA splitter) (1 source to 2 DVI Dual-link splitter)


    I am sure there would be cheaper alternative brands doing a similar thing but Gefen is a good reliable brand.


    Have you tried connecting both monitors directly to the Mac and using Mirroring?

  • MIKEinMICH Level 1 Level 1 (0 points)


    Hi John, thanks for the info. I am using this.  (Sorry for the huge images: )  It is attached directly out of the Mini DVI-VGA port. I do not see the mirroring option actually 26791.jpg

  • John Lockwood Level 5 Level 5 (6,445 points)

    The cable you showed is definitately a passive device and as far as the Mac is concerned counts as a single monitor. The signal is being reduced by having to 'power' two monitors, hence the dimming. The Gefen devices being powered themselves would not suffer this problem.


    To try mirroring you would have to connect one display to each of the two video interfaces on the Mac mini.

  • MIKEinMICH Level 1 Level 1 (0 points)

    Thanks for that.  This particular Mini - 1.83G Core2Duo only has the one video port (2009 model). 

    I would definitely do mirroring if I had a newer one with the extra video output.  Guess in this case

    I'd need to go with the amplifier device.


    I do have a 17" and a larger IMac with the external video port at another studio where i'd like to do

    mirroring...but will take some study to choose the right external Monitor to use to match the

    Resolution of the IMac's internal video display.

  • John Lockwood Level 5 Level 5 (6,445 points)

    The Mac mini (late 2009) does have two video interfaces, a Mini DVI, and a fullsize DVI. Both can be used to connect to VGA monitors by using appropriate adapter cables, or can be used with DVI monitors.


    I notice your cable came from Monoprice, they also do cheap active VGA spitters as you can see by going to

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