Oppo HM-31
HDMI Switcher

Oppo Digital HM-31 Advanced 3x1 HDMI Switch

Oppo HM-31

For connecting modern home-theater gear such as Blu-ray players, audio/video receivers (AVRs), game consoles, and, of course, HDTVs, HDMI is the way to go. Why? Because HDMI (High-Definition Multimedia Interface) can, via a single cable, transport audio, video, and other data signals in pristine digital quality between compatible devices. And with the exploding number of such compatible devices, it's increasingly likely that a person could use an additional HDMI port (or three). The simplest way to have multiple HDMI-enabled devices share a single HDMI port is through the use of a hardware switch. I recommend the Oppo HM-31 Advanced 3x1 HDMI Switch ($99 direct), which proved itself a very capable performer in testing. I also like the fact that the device offers useful extras such as an effective auto-switching feature and additional control options that give it increased flexibility for home theaters.

Inside the HM-31's retail box is the switch itself, as well as a 5V DC adapter, a credit-card-size remote control, and a nine-page user manual-no HDMI cable is included. The switch's glossy black plastic case is about the size of a paperback book at 1.1 by 7.4 by 4.25 inches (HWD), and it weighs 9 ounces. A trio of mounting holes on the bottom of the device can be used to secure the lightweight unit permanently. The face of the HM-31 features a power indicator light and a manual input selection button, as well as a trio of indicator lights that report the current state of each HDMI port. An RS-232 port on the back side of the switch can be used with programmable home-theater control systems, and there's an IR input for use with an optional external IR receiver.

The simplified remote is tiny and has only four buttons: three for direct port selection and a fourth that cycles through the active inputs-inactive ports are automatically skipped. Communication with the switch remained solid at distances exceeding 20 feet and at angles up to about 40 degrees off-axis. If the last thing you need in your life is another living-room controller, not to worry. The HM-31 is supported by Logitech's popular line of universal remotes.

On the device are three HDMI inputs and one corresponding output. The switch's HDMI ports are compliant with the current HDMI v1.3 spec, which can support video resolutions up to 2,560 by 1,600 pixels at 75 Hz-well beyond 1080p resolution. HDMI v1.3 compliance also paves the way for lossless audio support, including such formats as DTS-HD and Dolby TrueHD.

Oddly, there's no mention of the HM-31's useful auto-switching feature in the user manual or on the box. I did, however, find this information on Oppo's excellent product support page . Ideally, an auto-switching HDMI switch detects when a connected device is powered on and automatically switches to that port. The HM-31 takes this ability a step further by prioritizing its three HDMI inputs so that if an "always-on" device, like a DVR, is added to the mix, it doesn't throw a monkey wrench into the whole auto-switching process.

For example, in my test setup, I connected a Dish Network ViP622 DVR to input port 3 on the HM-31 (lowest priority), the Samsung BD-UP5000 Duo HD player to port 2 (mid-priority), and a Sony PlayStation 3 to port 1 (highest priority). Even though the DVR was always active (it displays a splash screen when in stand-by mode), turning on the BD player would cause the switch to select its port automatically. If I left the disc player running and turned on the PS3, the HM-31 gracefully switched to that device. Likewise, turning off a device connected to the switch's port with the highest priority resulted in the switch automatically selecting the active device connected to the next-highest-priority port-with my always-on DVR connected to the port with the least priority. Timed measurements showed that activating a device connected to a port with higher priority resulted in a near-instant selection of that port; auto-switching to a lower-priority port took the HM-31 an average of 12.7 seconds. Keep in mind, however, that adding a second always-on device to the HM-31 would effectively negate its auto-switch capabilities.

In addition to its fancy auto-switching, the HM-31 features an HDMI equalizer function. According to Oppo, the EQ "removes distortion from the input HDMI signal after it travels over long cables and restores the signal quality/strength." Oppo also claims it has successfully transmitted 1080p material using 50-foot HDMI cables. I didn't have a pair of 50-foot HDMI cables handy, but I did use a 40-foot HDMI cable to connect a Sencore VP403 video signal generator to the switch, and a 25-foot cable from the switch to an HDTV. With everything hooked up, my 1080p60 and 1080p24 test video signals (which included various high-quality test patterns) were transmitted perfectly. That's fine, but it is worth noting that I've yet to experience an HDMI switch failure when using my 40-foot and 25-foot cable lengths-it may be time to increase the challenge by adding a longer, 50- or 75-foot run to my test setup.

The HM-31 also had no trouble passing along a 1,920-by-1,200 (60 Hz) PC signal to a compatible LCD monitor. Audio timing tests using the Blu-ray version of Joe Kane's excellent HD Basics reference disc revealed no sync or other audio anomalies being introduced by the HM-31.

The Oppo HM-31 is easy to recommend to anyone who needs a few more HDMI ports, especially given its clever auto-switch capabilities. The lack of an included HDMI cable appears to be common with switches at this price, and, considering how inexpensive HDMI cables have become, I don't find this a deal breaker. Perhaps the only complaint I can level at the HM-31 is that it has only three HDMI inputs. A six- or eight-port version of this switch would be truly awesome, but even the current three-port version is well worth our Editors' Choice award.