How to setup dual display on your Macbook Air via HDMI

Posted by Winston

Thursday, 20 December 2012 06:28

I've been looking to share my screen from my Macbook Air on two monitors (duplicate/clone) ... and there was not many options available. The guys at the Apple stores says it can't be done ... while I went to all the hardware stores to look for a mini-DisplayPort splitter ... it doesn't exist. So what can I do?

There are two options ... spend over $200 USD for a Matrox DualHead2Go or similar, which apparently has some incompatibility issues with the Macbook Air or around the same price ... go for a bulky VGA splitter box, which again isn't really what I wanted.

It took me a while to figure this out ... but finally I have a workable solution! In this article we will show you how to setup dual display for your Macbook Air via HDMI (duplicate/clone screen only). It even works with the lid closed (thanks to the FREE NoSleep app).

Now you're thinking the Macbook Air doesn't have HDMI output ... and you are correct. It only has one mini-DisplayPort or on the newer Macbook Air, oneThunderbolt connector. So how do you get HDMI output on the Macbook Air. Well, the only way to do this is to use a mini-DisplayPort to HDMI converter/dongle, which Apples sells for around $35.00 USD. Generic ones will cost much less around $8 USD.

The Things You'll Need

Next, you'll need 3 sets of high quality HDMI cables and a HDMI splitter box (like the one pictured below). If your monitors does not support HDMI, then you can always get the HDMI-to-DVI cables. You'll need two of of these and one high quality HDMI cable.

Now, HDMI splitter boxes can cost quite a bit depending on build quality and brand, so shop around for bargains ... for me, I got the cheapest one available on the internet costing me around $25.00 USD.

And finally, you'll need a Mac app called NoSleep. It allow you to close the lid on your Macbook without going into sleep mode, which is really annoying. It's free and you can download it here. Here's a summary of the things you'll need...

1 x HDMI splitter box (1-in, 2-out)
1 x Mini-DisplayPort-to-HDMI converter/dongle (pictured above)
1 x High quality HDMI cable (to connect with the dongle to the HDMI splitter box)
2 x High quality HDMI cables or 2 x HDMI-to-DVI cables (one for each monitor)
NoSleep v1.3.x Download it here.

The HDMI Splitter box

The HDMI splitter box has 1 x HDMI input and 2 x HDMI output. Each port has a green LED, which lights up whenever there is a signal. It's power by a 5V power pack and supports HDMI version 1.4.

How It's Connected

As you can see from the images above ... all the cables connected to HDMI splitter box. Photos 1 and 4 shows the Mini-DisplayPort-to-HDMI converter/dongle connected to the Macbook Air. This is then connected to one of the HDMI cables, which goes to HDMI splitter box. Photos 2 and 3 shows how the rest of the cables connected. Here I'm using 2 x High quality HDMI cables to connect to the two monitors.

Dual Monitor on a Macbook Air (in action)

Mirror/Clone ONLY. With the Macbook lid closed running on different monitors. In this scenario, all screens will run at the lower resolution of the two. Remember, this solution only gives you Mirror/Clone/Duplicate mode ... you can not run a extended desktop or run the monitors at different resolutions.

NB: However, having said that ... you can run your Macbook with an extended desktop, but both monitors will be duplicated (extended), while the laptop will be the master screen. These settings can be adjusted on on your Macbook via the System Preferences > Displays options.