MacMost Now 342: Using Multiple Monitors With Your Mac

It is easy to hook up a second monitor to most Macs. Once you get a monitor and the proper cables to connect it, you can use the Displays preferences to control how the monitor fits into your desktop.

Video Transcript
Hi, this is Gary with MacMost Now. On today's episode, let's look at using multiple monitors with your Mac.
So, Macs have always been great about allowing you to hook up more than one monitor. As a matter of fact, all of the iMacs that have been out for a while now have had a video port on the back that you can use to hook up a second monitor. All of the MacBooks, of course, come with video out, and the MacPros come with two video outs, allowing you to hook up two monitors.
So, the first thing you need to do, of course, is get a second monitor, and you have to see what type of input it takes. You should get something with at least DVI. A VGA input, that's so old school, and it's not as good a quality connection as DVI. You can get a DVI LCD display, pretty cheap now.
Now, it's the matter of hooking up your Mac's port to that monitor. So, it depends on what you've got. If you have a new Mac, you've got the mini display port out, and you need to get an adapter to go from mini display port to DVI.
If you have an older Mac, you may already have DVI, or you may have a simpler connection like mini DVI. Then, you just have to get the right adapter to go to DVI to hook up the second monitor.
Then, once you have two monitors hooked up, you want to go to your System Preferences, and go to Display Preferences, and then this is where you control how your Mac uses that second monitor.
So, here we are in the Display Preferences. And you can see the normal tab display allows you to look at the different resolutions for the current display. You can click gather windows, and it will show you both windows for both displays.
Otherwise, it displays each of those windows on its own display. Then, if you go to Arrangements, you can decide how you want these monitors to line up. In other words, how the cursor goes from one screen to the other. You could basically click and drag your second monitor around to where it should be relative to the first monitor.
You can play with different settings. Just drop it and it will change it. And then you can test out your new arrangement and try another one. Now, another thing you can do on Arrangements is decide where the menu bar goes. You click and drag the menu bar, and you can drag it to one monitor or the other.
Because you control which is the primary monitor where the menu bar will be displayed. Now if you check off 'Show displays in menu bar', then you will be able to control a lot of this through the menu bar icon, here. You can change the resolutions, turn on mirroring, you can also show the number of recent resolutions for each monitor and go to the display's preferences very easily.
Mirroring displays is mostly used when you are making a presentation using a projector. And, the projector doesn't have to be the same resolution as your primary display, like on your MacBook. It will just take the lowest common denominator and use that.
Now, if you do hook up your MacBook to a projector often, then you are going to want to use the Detect Displays command that you saw there in the drop down menu. This allows it to see the display if it doesn't happen to notice it when you first plug it in.
Getting multiple monitors can be very useful, especially with a lot of LCD displays being around 200 or even 100 dollars. You can hook up a second monitor and then get that much more desktop space out of your Mac.
Hope you found this useful. 'Til next time, this is Gary Rosenzweig with MacMost Now.

Comments: 37 Responses to “MacMost Now 342: Using Multiple Monitors With Your Mac”

    3/27/10 @ 9:54 am

    Hi Gary – Have you ever done a podcast on connecting more than two monitors to your mac? I’ve been investigating the Matrox Dual Head To Go, but would like to know your take on this. Thanks! Gene

    3/30/10 @ 2:17 am

    Hello Gary,

    is it possible to “mirror” the desktop to an external monitor but with a different resolution…for example 1920×1200 on the MB Pro and 1240×1024 on the external TFT?
    I was surprised that I can’t find this option because it pretty easy on Windows and works also on Ubuntu…

    Thanks in advance

      3/30/10 @ 7:13 am

      You definitely can mirror it, but it would be at the lower resolution. Otherwise, there aren’t enough pixels to display it on the second monitor — squeezing 1920 down to 1240 would look horrible. Is that what you are trying to do?

        3/31/10 @ 7:24 am

        Thank you for answering so fast…I guess mixed something up there.
        I thought that in my “windows days” I was able to run the laptop and the projector both at native resolution..but maybe it wasn’t like that…

    7/6/10 @ 4:21 pm

    Hi Gary,
    I have hooked my macbook pro to my IMAC using the Belkin Mini DisplayPort to Mini DisplayPort in order to use my IMAC as an external monitor. However nothing happened when I made the connection. I can’t figure out how to get them to communicate.


    8/30/10 @ 12:39 pm

    Hey Gary,

    I’ve got a mini dv to hdmi connection done to my LCD Full HD television. Images are coming fine but no sound! It’s still playing from my macbook.
    Also, I haven’t understood what’s happening with the whole dragging the smaller monitor around the main one…is that a viewing style of 2 screens on one?

      8/30/10 @ 1:14 pm

      Which adapter are you using? Does it support audio? Some do, and some don’t. If it is supposed to support audio, have you checked your System Preferences, Sound? Make sure it is selected as the output device.
      Otherwise, you’ll need to ask the manufacturer for support.
      I don’t understand your second question, sorry.

    1/27/11 @ 11:46 pm

    so I want to connect two LED Cinema monitors to a mac miniā€¦ possible? or do I have to go mac pro?

      1/27/11 @ 11:57 pm

      Well, you’ve got a Mini DisplayPort out from the new Mac minis. You could probably turn that into a Dual-Link DVI and then split that into two monitors with a series of cables and then hook that into two displays if they aren’t too high resolution. But I’ve never heard anyone try it.
      With a Mac Pro it is just a matter of using two video cards, or a card that supports two video outs — which I think is the default.

    Louis V
    9/15/11 @ 8:34 am

    Hey Gary,

    I was wondering if it was possible on a Mac Pro to connect two displays to the default Mini DisplayPorts and then at the same time could I connect a projector to the DVI port? Would this work at all? Thanks in advance

      9/15/11 @ 8:37 am

      You could add one display to each, but I don’t think you can add two to one of them.
      If you have a Mac Pro then you can simply get another video card — fill it up with video cards and add many displays if you want.

        Louis V
        9/15/11 @ 8:53 am

        Thanks great!! Thanks Gary!

    Kelly Small
    12/25/11 @ 3:15 pm

    My son has a DVI monitor working with his Macbook Pro. My concern is what is the correct procedure for connecting or disconnecting the mini port cable? Is it hot-swapable such that we can plug or unplug it anytime while the laptop is running? Or do we need to go to sleep/shutdown before changing the hookup?

      12/25/11 @ 4:10 pm

      It is “hot-swappable” yes. People with present using projectors and such do it all the time.

        Kelly Small
        12/25/11 @ 4:52 pm

        Thanks, I figured it was but wanted to make sure. They really need to document things like this.

    John Witte
    1/11/12 @ 6:18 pm

    I have an iMac 17 inch with a bad monitor. I have hooked up an external VGA monitor (connected to mini-DVI) to it so I can continue working on it until I get a chance to replace the entire unit (cost-prohibitive to fix). Problem is, that when I hook up the external monitor, it thinks it is a second monitor and I still cannot get to preferences. All I want to do is mirror the “bad” monitor so I can use it. Is there a way to do this using hot-keys ? I know it would be easy if I can just view the main monitor and get into System Prefs, but doesn’t appear to be an option. Any help would be greatly appreciated.

      1/11/12 @ 6:30 pm

      Depends on your Mac and version of OS X. Try holding down the option key and pressing the brightness button (usually F2). You may need to hold down the “fn” key at the same time.

        John Witte
        1/11/12 @ 8:11 pm

        Thanks for your rapid response Gary ! Unfortunately, I cannot remember the OS version of this particular Mac … about 3 yrs old if that helps. I tried different variations of these suggestions to no avail. Is there a Mac equivalent to RDP so i can remote in from another Mac as admin and change this setting ? … so close and yet so far.

          1/11/12 @ 10:18 pm

          RDP? Do you just mean VNC, or Screen Sharing as it is called on the Mac? That’s built in. But if it isn’t turned on, then you have the same problem of being able to get it going by getting to System Preferences.
          Oh, also try Command+F1 or Command+fn+F1 just on the off-chance that it works (supposed to work, but on MacBooks)

    John Witte
    1/12/12 @ 9:25 am

    Hi Gary, yes I mean something like VNC and unfortunately it doesn’t seem to be turned on. Seemed that Command+F1 or Command+fn+F1 didn’t do the trick either. On a last-ditch idea… is all of the screen setting data stored on the physical hard disk ? I do have a couple of identical Macs in the office. If I was do take the drive out and replace it in another Mac… then set it up as I desire ( with mirroring on ). Then, put the drive back into this unit… do you think the settings will stick ? Just an idea I had while driving back to the office this morning. Thanks again for all your suggestions!

      1/12/12 @ 10:18 am

      Possibly. Maybe in a plist file in the Library/Preferences folder?

    John Witte
    1/12/12 @ 10:42 am

    OK,I will try this and report back my findings Gary. May take me a day or two to get this all accomplished.

    John Witte
    1/16/12 @ 10:53 am

    Greetings. Just wanted to let you know how everything ended up. Was able to get them to mirror using the following:
    1.) Option + F14 – This brought up a “Sys pref” window on the 2nd monitor.
    2.) Clicked on “Gather Windows” button.
    3.) This brought up the Display Options. From there, I clicked on “Arrangement” and then checked the “Mirror” box.

    This combination accomplished what I needed and now am able to use this Mac until time allows a new unit to be set up.

    1/16/12 @ 11:26 pm

    Gary – where are the settings to control what happens to the external display/projector when I close my macbook pro – i.e. if I close my macbook pro does it turn off the feed to the external display? Can I change settings so that I can close my macbook pro and still have a feed to the external display?

      1/17/12 @ 7:45 am

      No settings that I know of. You simply need to have the display connected to the MacBook. I haven’t tried it in a while (with Lion) but it used to be that if you had an external display connected, and a mouse and keyboard connected, that the MacBook would then continue to work with the lid closed.

        1/17/12 @ 12:34 pm

        Thanks Gary

    4/16/12 @ 9:22 pm

    Hi. I have a MBP (OSX 10.7.3) and I am using a Full-HD LCD TV as an external monitor, set as a primary screen. I’m using the built-in trackpad and keyboard on the Mac, obviously the lid is open, but I don’t want to use the screen on the MBP.
    As this is the secondary screen, I just reduced the brightness until turn it off, but this is not an entirely solution, the secondary screen is still active on the system. I can still drag apps on it. I don’t want that to happen.

    So, the question is, when using an external monitor as a primary screen, how can I turn the secondary screen off? Thanks!

      4/16/12 @ 9:31 pm

      The only way I know of to not use the MacBook’s screen is to have it closed — with an external keyboard and mouse/trackpad.

    5/4/12 @ 2:18 am

    Greetings. I currently have a triple LED monitor display for my pc. I want to hook up my Macbook pro. I have seen that it can be done with a Matrox triplehead2go, but that requires a mini display port to display port adapter, and 3 display port to DVI adapters.

    Do you know of a more elegant solution ? Thanks!

    5/7/12 @ 7:15 am

    Hi Gary,
    I have a newer model iMac (2011, right before lion released), and I have a 2nd monitor attached, using a miniport to dvi. I am also attempting to connect a cintiq at the same time. On my old windows pc, I was able to have the extra monitor and cintiq running at the same time (the cintiq would just display the same as my second monitor using a splitter) Unfortunately, I am not able to use the splitter on the iMac configuration. It seems to stop both from working at all. I was just wondering if you have a work around for this?
    Thank you for your help!

      5/7/12 @ 7:29 am

      I’m surprised that a “splitter” worked for you before. Don’t know what sort of solution there is for this. I think the iMac only supports one additional monitor via mini displayport. Thunderbolt supports more, I think. Or, it could be you just need the right cable set-up. Maybe a visit to an Apple store or computer store and see what they have.

    6/23/12 @ 10:45 pm

    I have a mac mini with 3 tv’s hooked up to it. two of them run off vga cords and the same signal with a splitter and the other tv is hooked up with a hdmi cord. Every week through the preferences i put the display settings were i want them, and when i return the next week they are reset to what i believe is factory settings, How do i fix this so the settings stay where i want them?….. i change the preferences through the program i am running, not the system preferences, do the system preferences have anything that might be conflicting with the program?

      6/24/12 @ 1:02 am

      You don’t mention what “the program I am running” is. That’s probably the key. Why not change it in System Preferences?

    6/30/12 @ 2:53 am

    Hi Gary
    Thank you for your excellent podcasts – they’re really useful to a new mac convert!

    I have a question I hope you can help with.

    I have set up a second monitor on my iMac – but I continually get ‘dropouts’ where the screen on the second monitor goes black for a few seconds and then comes back on.
    This is so frustrating and I can’t seem to find any help on the net.
    Any ideas?

    (I have an iMac with 8GB and run OS X [10.7.4] – the second monitor is a Viewsonic VX712)

    Many thanks again


      6/30/12 @ 6:12 am

      No, sorry. No idea. Could be the monitor. Could be the cable. Could be the connectors. Could be the Mac. Impossible to know without being there.

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