There are certain instances where you’d want to use more than one display. Regardless of your reasons, multiple displays give you more screen real estate than a single monitor. Especially when you’re looking to add an extra monitor to your current setup, it’s cheaper to go for a second monitor than to buy an ultra-wide option, as they’re quite expensive.
But one of the challenges you may experience is connecting your dual-monitor setup. While it’s easy to set up two monitors using HDMI, a common misconception is that you can buy an HDMI splitter and be set. But that’s not true. An HDMI splitter won’t give you the results you need.
The mistake almost everyone makes about HDMI splitters
It might sound logical, but it’s a common gotcha
Most people buy an HDMI splitter thinking it’ll allow them to have extended displays. Extended, in this case, means that you can have the connected monitors display two different things. One could be for watching random YouTube videos or the latest news, while the other is dedicated to getting work done.
Sure, a dual-monitor configuration is perfect for almost everything, but HDMI splitters don’t work this way. It’s easy to assume that if you can have one HDMI cable connected to your laptop or desktop and two HDMI cables on the other end, then you can connect and use two screens separately. While you can connect to two screens, the screens won’t be independent of each other.
That is to say, instead of giving you extended displays, an HDMI splitter simply mirrors the two monitors. So while you’ll have two monitors connected, they’ll display the same information, which is probably what you don’t want. It all boils down to how HDMI splitters work.
How HDMI splitters work
Here’s what goes on under the hood
At its core, an HDMI splitter works by taking a video signal from one device (say your laptop, desktop, console, or streaming box) and duplicating it so that it can be shown on multiple video output devices at the same time. The key term here is “duplicate”, which means it takes a single video signal from your video output device and makes multiple copies of it. Yes, don’t assume the name “splitter” tells you how it works.
The name “splitter” in HDMI splitters is a bit misleading because it implies that the signal is split, and the connected screens will show different information, but these cables don’t work that way. Instead, an HDMI splitter takes that one signal, makes multiple copies of it, and transmits it to every connected display.
You can think of it like photocopying your homework—you’ll have multiple, identical copies. This is why, instead of seeing different information on connected monitors, they’ll show the same information, which defeats the purpose of having a dual-monitor setup. It doesn’t mean that HDMI splitters are useless. They’re just misunderstood.
How to actually get two displays to work
This is how you get a dual-monitor setup
So, if you want multiple displays to work independently, what should you do? Well, there are different methods that you can use depending on your output device. First, if your output device has multiple ports that can pass video signals, you can connect each monitor to a dedicated port.
For example, if your laptop has an HDMI and a USB-C port, you can connect one monitor to the HDMI port and another to the USB-C port if the USB-C port supports DisplayPort Alt Mode. If yours has a Thunderbolt port, that’s better because you’re assured it can transmit video signals. By far, this is the most reliable method of connecting multiple displays. In this setup, each port outputs its own independent signal, and thus, you don’t experience the mirroring issue of using an HDMI splitter.
Another option is to use a docking station, such as Selore’s USB-C Docking Station, which includes two HDMI ports and can connect to two displays thanks to DisplayPort Multi-Stream Transport (MST). However, MST is exclusive to Windows and not supported on macOS; as a result, you can’t use it to connect to dual monitors on your Mac. If you use a Mac or your Windows laptop doesn’t support MST, you can use a DisplayLink adapter or docking station, such as the Mosirui DisplayLink Docking Station.
Docking stations that support dual monitors rely on one of two methods: MST or DisplayLink. A docking station with MST won’t let you connect to multiple displays on a Mac. DisplayLink works across macOS and Windows, hence this is the one to get if you want cross-platform compatibility. You should pay close attention to how the docking station or USB-C hub achieves dual-monitor support before buying to avoid disappointment.
DisplayLink sends video over USB and can create multiple independent video signals for both macOS and Windows, even when your laptop only supports a single external display at a hardware level. This is the trick you can use to connect multiple displays to your M1 MacBook Air, even though the laptop only supports a single external display.
Don’t buy an HDMI splitter for the wrong reason
HDMI splitters duplicate video signals; they don’t create new ones. If you buy an HDMI splitter when you want to extend your dual-monitor setup, you’ll be disappointed. As always, before making a purchase decision, do your research, especially if you’re not familiar with the gadget, to avoid regrets.