Oppo HM-31 Advanced 3x1 HDMI Switch

The review hardware for this test was provided by OppoShop.com, a European-based online retailer of Oppo Digital products. Customers in the UK can order from OppoShop and experience fast delivery times without any risk of Import tax or duty charges.

Just a few years ago, if your TV had a digital video input at all, then you were basically guaranteed that there'd only be one of them. Even into 2006, when two HDMI inputs became the norm, some manufacturers (we love them really) persisted in including a solitary connector. Last year, 3rd inputs began sneaking onto the sides of TVs, and at the Consumer Electronics Show last month, it became apparent that 4 inputs is now the order of the day.

Yes, HDMI is quite blatantly here to stay, and the number of devices relying on this all-in-one digital connection for their AV output will surely continue to rise. Right now, we have HDMI-equipped standard and High-def DVD players, Blu-ray Disc players, Digital Cable/Satellite set-top boxes, PVRs, media servers, home cinema systems, amplifiers, video processors, computer video cards, laptops… not only that, but most of today's games consoles utilise HDMI for their highest quality video output, and many people own both of them. It's enough to make your head spin, and it's safe to say that having even 3 or 4 of these inputs on your HDTV, projector, or video processor, still might not be enough for some.

Oppo Digital, already famous for their quality, affordable DVD players, have come to the rescue with the HM-31 "Advanced 3x1 HDMI Switch". Plain and simple, it's an HDMI switch that accepts 3 inputs and sends the currently selected A/V signal to its one output. At €104 delivered (that's £78 or so in our olde money), it's not the cheapest device to perform this task, but there's a few quality-related reasons for that: firstly, the HM-31 contains a signal equaliser, which aims to prevent signal drop-outs, which typically appear as flickering white or green pixels on the picture. These annoying pixel-sized drop-outs can crop up when long HDMI cable runs are used with High Definition resolutions, as HDMI is at its most error-free with short cables and lower-resolution video.

Secondly, the HM-31 is, according to Oppo, one of the very first switches "to pass the HDMI 1.3 certification test". In practical terms, HDMI 1.3 is, for many applications, a lot of hype, but it's true that the 1.3 spec does involve higher signal bandwidth. Knowing that the HM-31 can accommodate this not only means that it's future-proofed, but is also a good sign of a well-built product.



Lastly, the HM-31 features an RS-232C port on the back. It won't be of consequence to most, but RS-232C is a communications protocol which is used for in automated home theatre systems, as it allows devices to talk to each other (for example, commands to dim the room lighting, part the curtains, drop a projection screen down from the ceiling, turn on the projector, and set the switch-box to the necessary input, could be sent to this port). The HM-31's inclusion of this feature will allow system installers to fully integrate and automate the switch's operation.

Build Quality/Appearance

Unboxing the HM-31 is much the same as unboxing Oppo's other products. It's well packaged and comes wrapped in one of Oppo's usual classy black canvas-like bags. It comes supplied with a suitably minimalist remote control (which features input selection buttons for each of the 3 inputs, as well as another to cycle between them), a sticky adhesive pad (in case you want to mount it to the wall), and a power adapter. (Although OppoShop are based in Continental Europe, UK customers will receive the appropriate power adapter).

Ironically enough, in terms of size, the HM-31 reminded me of a compact 56k dial-up modem I used to connect to the internet in the late 90s. (Thankfully the comparisons end there, because installing and using the HDMI switch was completely straightforward!) It's black and closer inspection reveals a subtle brushed metal finish, as well as mounting holes on the back, so you can attach it to the wall (see illustration). The surface is a little glossy, which means that it can pick up fingermarks, but as a device you're not likely to be touching much, this didn't bother me as much as it has in some other instances.

The front of the unit has four LEDs – one for Power, and one for each of the three inputs. These LEDs actually give you feedback on what's going on – they'll light up red if an HDMI device is connected and powered on but not selected, and the input you currently have active will light up blue. If you've deliberately seleted an input which has nothing plugged in, the blue light will blink, cackling silently and reminding you of your error.

The HM-31 also features a manual Select button on the front, so you can still operate it even if you lose the remote control down the side of the couch.

But, even then, manual control isn't necessary, because the HM-31 auto-switches between inputs. Upon turning one connected HDMI device off and then turning on another, the switch will automatically detect the new device and switch inputs automatically, which is incredibly convenient and means that for many applications, you can basically forget that the switch is there! (The only time you'll need to manually jump between inputs is when you have more than two or more devices actually powered on at the same time).

Testing

It might not make for the most thrilling review, but the HM-31 does exactly what it says on the box. I tested it with a 1080p HDTV and a Sony 1080p SXRD Projector as input devices - both of which only have two HDMI inputs, despite the latter of which being a recent product. For sources, I used Panasonic and Oppo DVD players, DVI-based desktop and HDMI-based laptop PCs, an Xbox 360 Elite, and a Playstation 3 - all of which output a variety of different resolutions, scan-rates, and signal types. The HM-31 never operated anything less than perfectly.

To seperate the HM-31 out from the cheaper switches, I decided to put its signal equalisation function through its paces, and tested it with cables of longer length. As a new owner of a projector, I now have to share a Playstation 3 between it - for watching Blu-ray Disc films on - and a TV, for up-close analysis of video transfers, and for when I'm doing DVD authoring and compression work and don't want to use up precious projector lamp time. This requires the use of a good quality HDMI cable, which is around 6 metres in length (in my setup, the PS3 is on the other side of the room, near to the projector). When connected with another switch, which performed just fine with short cables, this set-up presented problems in the form of white pixel drop-outs scattered across the image, which wasn't too surprising, as HDMI is fairly well known for such issues with long cables. But, replacing the previous switch with Oppo's HM-31 solved the problem and presented a completely trouble-free image, even at 1080p/60, the most bandwidth-hungry type of video accepted by today's HDTVs. (Regrettably, I didn't have the opportunity to test the switch with any "Deep Colour" sources).

It's also worth noting that the HM-31 has an Infrared Extender port on the back. This means that you can plug an additional IR module in and hide the switch away from view. Oppo doesn't include the IR module with the HM-31, but because it's a small, slick-looking unit which can be wall-mounted, I don't see anyone wanting to hide it away. Also, it has two of its own Infrared receivers built in, in the less than usually likely event of you needing to give it remote control commands, it should be able to pick them up.

One other convenience feature I should note: when you press the Cycle button on the remote (which cycles through Inputs 1, 2, and 3, then back to 1 again, in that order), I was pleased to see that the HM-31 skipped over an inputs when the device connected to it wasn't turned on. It's nice attention to detail and gives you one less reason to wonder "why am I only seeing a black screen?"

Conclusion

The HM-31 isn't the cheapest HDMI switch on the market, but it's also not the most expensive either. If you've run out of inputs on your TV, don't have an HDMI-equipped A/V receiver, and want a well-built switch that will still perform under trickier conditions, then it's a solid choice which I highly recommended. Once you use an auto-switching HDMI box like this, it's difficult to go back to one that requires manual control.

Although the price certainly isn't unreasonable, I'd ideally like to see Oppo include an HDMI cable as part of the package, like they do with their excellent DVD players, just to seal the deal. I've heard of a lot of people who've bought HDMI switches but forgotten that they'll need an extra cable to connect the switch to the display – and yes, I'm one of them!