Testing: Avegant Glyph Head-Mounted Display

By Norman Chan

I use Avegant's personal home theater player for a week to watch movies, TED talks, and basketball games.

The Avegant Glyph is not a virtual reality headset. Despite VR being a hot topic these days, this head-mounted display is just that: a display you wear on your head to watch video and listen to music, kind of like those Sony HMZ and Vuzix Wrap personal theaters that we skip covering at CES. But what makes the Glyph interesting and a better device than those other HMDs is its use of a new kind of display technology--one that's more akin to a home theater projector than a flatpanel. I've been testing the Glyph Founders Edition headset for about a week, and have found it great for comfortably watching video piped from my smartphone on the couch and while lying in bed, but have really enjoyed using it with drones.

First, let's talk about the unique display technology in the Glyph, which Avegant has been calling a "virtual retinal" display. That's marketing speak for DLP projector tech--Glyph employs two tiny 720p DLP projects that shine and bounce light into your eyes. Each projector shines the equivalent of a million pixels, but those pixels aren't like the individually-lit dots in LCDS or OLEDs, they're light reflected from micro-mirrors. The result is an image that has a very high pixel fill--I can detect basically no screen door effect in the 16:9 image.

The image doesn't wrap around your entire field of view, though. Glyph's display has a 40 degree FOV, which makes it look like a 75-inch TV in your living room. There's definitely the sense of some space between the image and your eyes as well--which captures some reflected light from the "screen"--which to me looked like sitting in the middle of a big theater with ambient light bouncing off the walls.

It's fair to wonder why Avegant shipped the Glyph with 720p DLP modules as opposed to TI's new 1080p chipset, and I guess it's due to product development lead times and supply costs. But the good news is that 720p looks really good in the Glyph. With the high pixel fill, pixelization is almost non-existent, though low-bitrate video compression artifacts did stand out. The only place where the resolution is really noticed is in the aliasing of on-screen text, such as when navigating through a connected phone's home screen or trying to browse the web. This is a device made for watching video, not reading e-books.

Over the past week with the headset, I sought out places to use the Glyph instead of just watching a video on my iPhone. The design of Glyph makes it possible to use it as headphones in public, and then sliding the head band down over your eyes to watch video (let's call it "La Forging"). In practice, I rarely found it practical to drop the Glyph over my eyes to watch video while in public, like on a bus ride. The places I ended up using it was almost always at home, either lying on the couch or in bed.

It takes a bit of time to find the sweet spot for the image.

It's not that the Glyph is awkward to wear--it's actually pretty comfortable, and comes with several nosebridge adjustments that easily pop out with magnets. I didn't need to use the included headstrap either, and it never felt too heavy on my head or tight around the temples. What's more clumsy is the time it takes to get properly situated with the Glyph, when you just want to watch a short YouTube video. Built-in IPD sliders and focal knobs (compensating for +1 to -7 eyesight) meant I never had to wear my glasses with the Glyph, but it also takes a bit of time to find the sweet spot for the image. There's even a dedicated button on the headset to help you calibrate the lenses, and I had to go to that pretty regularly to make sure my eyes weren't straining to focus.

Video is piped in via a micro HDMI port, and Avegant has included a really nice cable with the headset (good length and really flexible). For video from smartphones, you may need an adapter to get HDMI out, like Apple's $50 Lighting Divigal AV connector, which does some encoding work for iOS. Most of the video stream from the iPhone worked just fine, from YouTube to TED talks to Netflix. In many cases, though, video will play on both the phone and the Glyph, so you're draining battery pretty heavily on both devices at once. My phone would occasionally get hot when streaming video. I wish someone would make a dedicated portable video player with HDMI out, like of like an iPod Shuffle for video. That'd be the perfect accompany device for the Glyph.

But once I was situated with the headset, watching longform video content was pretty great. I used the Glyph to watch all of a Warriors basketball game streamed from my phone, and a few episodes of Rick and Morty. As with my experience with the Gear VR, animated content looked best in the HMD, partly for its native 16:9 aspect ratio and lower dependency of high bitrates. Eye strain never became a problem, and because the Glyph doesn't completely block out your view of the outside worth with eye gaskets, I never got nauseous while using it. The four hour battery life claim is accurate, as long as you're watching on the lowest brightness setting. Honestly, I would prefer the Glyph give me the option to go even darker.

(One nitpick--the display doesn't seem to know whether an HDMI source is plugged in or not, and won't automatically turn itself off when disconnected from a video source. I've had the battery drain overnight more than once just from forgetting to flip the power switch after use.)

Glyph also supports 3D video playback, though only in a limited way. SBS (side-by-side) 3D, like what you can find on YouTube, works just fine. You long-press a button on the side of the headset to activate it, and the stereo imagery is enjoyable. But that's technically 3D that's half the resolution of 720p--each eye is getting 640x720 pixels worth of data. Watchable, but not very sharp. SBS 3D is the only supported stereo system with this launch; there's no 3D Blu-ray playback.

The design of the Glyph makes it blend in with big headphones like Beats, and it's clear that Avegant wants you to pack its headset in your bag instead of a big pair of cans. The audio quality, however, wasn't very impressive. It's serviceable for watching video, but I found the bass lacking and the volume controls finicky. The sound simply didn't make me say wow. And while you get audio passthrough over HDMI, dedicated music playback is limited to a 3.5mm jack (which doesn't override HDMI, either). There's actually a Bluetooth receiver inside the headset, but it hasn't been activated for audio.

As a media playback display, the Glyph isn't changing how I consume mobile video on a day to day basis, but one area where it has huge potential is as a display for quadcopter video. Both at CES and on trips this past week, I used the Glyph as a viewfinder for the DJI Phantom 3, using to stream live video from the quad over DJI's Lightbridge system. Here, the benefits of the DLP tech were immediate--the Glyph is easily the highest-quality FPV headset I've used, and far better experience than looking at the live drone video on a tablet or phone. The little bit of latency over the Lightbridge system was low enough so that I could fly comfortably with just the Glyph, and it was easy to still maintain line of sight on the quadcopter since the headset doesn't block out my entire field of view. Glyph also has a built-in IMU that works out of the box with DJI's Inspire 1, so you can use it to control the drone's camera gimbal, turning your head into a camera joystick!

Grant from Avegant and I fly some drones using the Glyph.

The last place I need to test the Glyph is on a plane ride, so I'm bringing it along this month on a long overseas flight. But unless in-cabin use of Glyph radically improves my flight experience, the headset is just bulky enough that I would hesitate to bring it instead of my favorite pair of headphones, just to be able to watch video. At $700, the Glyph is a high-end accessory for relatively niche use cases. Fortunately, with the IMU and 3D support, there are more of these niche uses than you would think for a traditional non-VR HMD, which in aggregate could make it worth your money. I'm likely going to keep it packed with my drone. As a first-gen product, I'm glad it's not half-baked. But it still is very much first-gen, meaning it's more a proof of technology than a must-buy.