Today I host another fantastic guest post written by VR ergonomics expert (and friend of mine) Rob Cole. Rob is a big fan of PCVR (he even tried to design a new SteamVR controller, do you remember?) and recently he had the opportunity to go hands-on with the high-resolution Pimax Crystal headset. He wanted to write on my blog his opinion on this device to inform the community and of course I accepted, because I’m more than happy to host another one of his super-detailed articles.
Rob… the stage is yours 🙂
Introducing Pimax Crystal
Following my test of the Pimax Sword controllers for Skarredghost last year, an opportunity arose to test Pimax’s new “Crystal” VR system, boasting very high-resolution displays, glass optics optimized for clarity, and their first 6DoF inside-out tracking system with joystick motion controllers.
After their very successful Kickstarter campaign for the 8K ultra-wide headset, Pimax made their name offering the widest field of view in the consumer VR space, to the delight of many simulation and VR enthusiasts.
The next generation included the introduction of their “Reality 12K” headset, followed by the announcement of Crystal, which had a much more specific focus, in Pimax’s own words:
“The highest pixel amount of any consumer VR headset, packed with tons of features to enhance image quality.”
Known as a very ambitious company, Pimax seems to be going from strength to strength with the Crystal and 12K headsets, as well as bringing their modular Portal gaming console and VR headset to market alongside Crystal.
It’s refreshing to see Pimax continuing to develop high-end virtual reality hardware, whilst other players have scaled back their plans, canceled projects, or just offered….radio silence.
Regarding the 12K headset, this was still some way off, with a 12K demo planned for Q3 of 2023, a roadshow in Q4, and a presentation at CES in January 2024. There is now a good chance we could see something towards the end of this year, with a potential release to consumers in 2024. This is the latest news on 12K directly from Pimax:
“The Pimax 12K QLED is processing and we are happy to announce we’ve completed over 70% of the work certifying the development of the process. Most of the 12K QLED components are shared with the Crystal, so you will see the many shared systems when seeing reviews and hands-on with the Crystal.
As with any development effort, there have been challenges with the 12K QLED that we have to overcome and a few that still require optimization. The nice thing about the work on the Crystal updates on the software and firmware sides is almost all of it applies to the 12K.”
After some communication with Pimax, an NDA was signed, where I promised not to spill the beans, until the appropriate time. Shipping of a Crystal pre-production sample unit was arranged with the understanding that this was to be a “PCVR Preview” as several hardware features were not yet enabled, though physically present in the hardware build.
These new features would include eye-tracking, dynamic foveated rendering, IPD auto-adjustment, and stand-alone mode: these will be enabled through future software updates. A wireless module and Steam VR “lighthouse” faceplate have also been announced as currently being in development, for release later this year.
My initial test was to find out what the tethered PCVR experience was like, before being able to try out the full range of features over the next couple of months. This would be my second test of hardware from Pimax, following last year’s Sword controllers. After receiving the tracking information for my Pimax Crystal shipment, I looked forward to what would be my first time using a Pimax VR headset.
The first article in this two-article series is an introduction exploring the specifications, showing some key features and my initial observations of setting it up and getting it running. The second article of this series will be released later this year, once the software updates have enabled the extra features of the system, and it will be possible for me to give a more balanced view of the Crystal as a finished product.
Unboxing
Much quicker than expected, my delivery arrived. Many thanks to the marketing team at Pimax for the use of this loan unit for this “preview”, and for some longer-term testing as additional features are activated with software updates.
Two boxes arrived by secure courier, a large box containing the complete Crystal system (including a fiber optic tether) and a small box containing a copper tether cable.
The outer cardboard sleeve of the large box had taken some impact damage on one corner, probably from bouncing around the inside of a courier van underneath a bunch of other packages.
Thankfully, the Pimax box inside seemed intact, though it had a little crease in the same place as the outer. The interior box was made of thick cardboard with foam inlay and seemed to have done its job of protecting the headset from transit damage.
The Crystal was snugly packed, with its motion controllers end to end inside a foam structure to prevent them from damaging the interior of the headset. A pair of batteries, a battery charging cradle, a spare “comfort” face cushion, USB leads, and fiber optic tether cable were all included, and DMAS speakers were already fitted (an optional upgrade).
Crystal Headset
Once the Crystal headset and controllers were set free from the packaging, I sat them on a cushion in my VR room and took some photographs. Since a picture paints a thousand words, here are two images showing some of the different parts of the Crystal headset, with my labels indicating the different parts.
Everything is laid out logically, though the adjustment buttons are a bit too easy to accidentally press whilst putting on or taking off the headset, or when making adjustments to the fit whilst wearing.
The interpupillary distance can be quickly adjusted using two physical buttons on the top left face of the headset casing (as seen in the image above) or by using Pimax’s new client software on the PC.
Either method activates a small motor providing an adjustment range of 58mm-72mm which should cater to most users; the average IPD for men and women in many populations is around 64mm and 62mm respectively. There are also additional IPD “offset” adjustments available in the Pimax PC client, on a per-eye basis, to allow further fine-tuning.
After years of using mechanical IPD adjusters, it felt very sci-fi to hear the whirring noise of the motor whilst the headset adjusts the lens separation. As eye tracking and automatic IPD were not yet working, I would set my IPD of 63.5mm as a starting point, taking this information from my last eye test.
The Crystal uses a well-proven style of headset harness: an adjustable top strap and adjustable rear cradle, with padded face and head cushions. This has worked well for successful PCVR headsets like the Vive Pro, Valve Index, and Pimax 8K, offering a useful range of adjustment to accommodate as many different head shapes and sizes as is practically possible.
Sound is provided by extra-aural (off-ear) speakers, always a welcome feature removing any physical contact or heat build-up typical of on-ear headphones. Boasting a similar BMR driver to the Valve Index, I looked forward to checking out the DMAS sound system with my favorite games.
Finally, two cooling fans underneath the removable faceplate provide active cooling for the computer, memory, and displays, helping to keep temperatures sensible inside the headset, whilst I couldn’t detect any noise from the fans during my testing.
Here is a closer look at some of the internal parts that come together to create the Pimax Crystal, starting with the display panels and optical lenses.
Displays
Crystal uses BOE 3.2” LCD panels boasting a resolution of 2880 x 2880 pixels per eye, providing a higher resolution than any other consumer VR headset currently available on the market. To give a total resolution (both eyes combined) comparison to other headsets:
- Pimax Crystal 5760 x 2880 pixels
- Varjo Aero 5760 x 2720 pixels
- Reverb G2 4320 x 2160 pixels
- PlayStation VR2 4000 x 2040 pixels
- Meta Quest Pro 3840 x 1800 pixels
- Valve Index 2880 x 1440 pixels
Of course, display panel resolution alone does not tell the full story, as angular resolution (often called “pixels-per-degree” i.e. PPD) is also determined by the field of view and the lens design. Crystal was unusual for Pimax in having a more regular FOV compared to their signature ultra-wide headsets and this was specifically chosen to maximize angular resolution, whilst still maintaining a good working field of view.
The Valve Index has 13 PPD, while Crystal offers 35 PPD, which is going to be a significant jump in resolving power. For reference, human vision (retinal resolution) is 60 PPD, which can also be expressed as “one arc-minute per pixel” (arc minute).
The Crystal uses BOE’s second-generation CLPL (customized low persistence liquid ) RGB vertical stripe display panels combined with the new technologies of “QLED” (quantum dot layer) and Mini-LED for backlighting.
The use of Mini-LED offers a “local dimming” ratio of 20000:1, whilst the displays boast a 100% NTSC color gamut for vivid colors with the enhancement of the Quantum Dots. Boasting much deeper blacks whilst offering up to 200 nits of brightness, which is almost double the brightness of earlier LCD headsets like the Index and Quest 2.
Motion-to-Photon latency is touted at 15ms whilst the refresh rate is either 90hz or 120hz. Finally, HDR content is supported using a special algorithm as the display panels are rated as 8-bit whilst true HDR requires 10-bit hardware.
Lenses
My Crystal came with a single set of 35 PPD aspheric glass lenses, described by Pimax as:
“Customized replaceable aspheric lens, with 35 PPD peak fidelity”
What is an aspheric lens? “An aspherical lens is a lens that is not spherical to combat spherical aberrations. This increases sharpness, especially at wider apertures, and reduces chromatic aberrations. Aspherical lenses are more complicated to manufacture, and with the increased image quality comes a higher price.” answer from SLR Lounge
I was aware some early units had shipped with polycarbonate (plastic) lenses which some users reported as showing distortion and chromatic aberration. Unsure which lenses my headset had shipped with, one user suggested “putting the lens in the fridge as the glass goes cold!” The first thing I did was to remove the right lens using the supplied tool, and weighed it on kitchen scales, to avoid putting anything in the fridge.
52 grams confirmed my suspicion it was a glass lens (the polycarbonate lens is only a couple of grams each), this can also be determined inside the Pimax software which sets the distortion profile according to information provided by the lens itself. With the Tobii eye tracking not yet active, I have ignored that aspect of the lens design though it’s visible on close inspection.
So what is the advantage of a replaceable lens? Yes, it adds cost, some extra weight, and more complication for manufacturing, but critically allows for damaged lenses to be quickly replaced (accidents do happen). This can save a headset from going to the electrical graveyard, as it’s not difficult to damage a lens, but often hard to source a replacement and tricky to successfully fit.
User-replaceable lenses also allow for different lens designs for different applications, depending on what the user is doing with the headset – productivity, gaming, movie experiences, etc.
At the time of writing this preview, an email has gone out to customers, informing them about a second set of lenses, which Pimax is still aiming to supply. These are described as “Optional Big FOV lens that increases FOV by 15%”. However, the resulting FOV number has not yet been determined, this is something I look forward to finding out during part two of this article later in the year.
The use of aspherical glass lenses is unusual in a VR headset, adding a good 100 grams of weight over polycarbonate lenses, but offering much higher optical clarity without glare or god rays, so well worth the weight penalty and extra expense of manufacturing.
It’s also much harder to scratch or damage a glass lens whilst cleaning or during daily use, compared to plastic lenses, so should be much more durable in the long term. And if damaged, can be quickly swapped out. Good work, Pimax!
Compute
Another more unusual aspect of Pimax Crystal was the inclusion of a Qualcomm Snapdragon XR2 processor, in conjunction with Pimax’s own “PC VR engine dual-processor” chipset with 8Gb of operating memory and 256Gb of storage memory.
As well as adding considerable cost to the product, it also adds weight. However, it’s important to remember this is a “dual function” device, with a small switch on the headset that allows the selection of the two modes:
- PCVR mode with 6DoF SLAM tracking. It sends tracking data back to the host PC running Steam VR, as well as eye-tracking, foveated rendering, wireless connectivity, and other functions. Can run Steam VR and OpenXR applications on the host PC.
- Stand-alone mode with 6DoF SLAM tracking where everything is self-contained on the headset, running Android-based VR applications. The XR2 processor is already used in other products like Meta Quest 2 and HTC Vive XR Elite, making porting of games much simpler.
Batteries
A big surprise to many, the Crystal headset requires a battery even for PCVR mode, the XR2 processor using the battery as its power source, despite the headset receiving USB power from the host PC through the tether cable.
Pimax supplied two curved lithium-ion batteries (6000mAh – 22.8Wh, 120 grammes), and a slim charging cradle which I first mistook as part of the rear head strap. There is also a small (120mAh) onboard battery to allow “hot swapping” during a play session, similar to the small internal battery used by the Pimax Sword controllers.
The battery is locked into place at the rear of the head strap, with small sprung loaded tabs on either side; these are very stiff when new and quite difficult to use, but repeated insertions make it much easier as the plastic parts start to wear in a little.
Charging each battery took about 2 hours using a smartphone mains charger, and run time was typically four hours before an on-screen “low battery” warning would appear. It was very easy to swap out the battery and turn the headset back on, confirming the small internal battery was working as intended.
The use of batteries may seem like an additional complication for PCVR users: usually the run time is only limited by the battery capacity of motion controllers as tethered headsets draw all their power directly from the PC. But eight hours of playtime from two batteries should be plenty for most people doing room-scale VR and one battery can always be charged whilst the other is being used and swapped out during refreshment or bathroom breaks.
For PCVR simulator enthusiasts using HOTAS, or wheels and pedals, the session can continue as long as they can stay awake! You can take very long flights in Microsoft Flight Simulator or some very long driving sessions when racing “24 Heures du Mans”.
Battery swap-outs could be more problematic for these long sessions, but as my seated “sim lite” sessions in Project Cars 2, Aircar, and House of the Dying Sun were always much shorter, it was never an issue. Later during my testing, I received a powered USB hub from Pimax, which aimed to support the battery by providing additional power through the USB lanes of the tether (more on this later).
Tether
The headset box contained a thin fiber optic tether cable, though as previously mentioned I had also received a copper tether cable as a spare, which proved very useful during testing as I had some connection issues using the fiber optic cable.
The big difference between the two tethers was the effect on room scale movement; the fiber optic cable was light, flexible, and nonintrusive, whilst the copper cable was heavier, noticeably stiffer, and felt more restrictive when moving about.
The fiber optic cable has one USB plug and one DP plug on the PC side, whilst the copper cable has two USB plugs to ensure power delivery, as well as one DP plug. The fiber optic cable is also a little longer at six meters, with the copper cable a more typical length of five meters.
The headset side of each tether plugs into a small DP repeater box and extension cable on the left side of the headset; the extension cable loops around the left harness hinge before plugging straight into the headset connector above the face cushion base.
The access to this connector is shrouded making it quite tricky to get right the first time, but if you gently work the connector through the opening in the casing you can slide it into place before snapping it shut.
Face Cushions
My Crystal was supplied with two face cushions, a standard cushion, and the “comfort” cushion which has a more substantial head support.
These are secured with Velcro onto a molded plastic base, which gently clips inside the headset casing. The plastic base looked quite wide, which could allow for much thicker face cushions to be fitted if required.
The headset came already fitted with the standard cushion, so I started using the Crystal with it still fitted, but it allowed too much movement causing the headset to freely move about.
Whilst the comfort cushion was a better fit, it still allowed the headset to move from side to side as there was still a noticeable gap on either side of my face. The comfort cushion also tended to make my head overheat, causing the lenses to get damp when trying out active games like Beat Saber. I planned to modify some after-market cushions later in my testing, to get the fitting dialled.
Rear Cushion
The rear of the head strap has a removable foam pad for support and comfort, also held in place with Velcro to allow easy removal for cleaning or replacement.
Whilst putting the headset on for the first time, I felt a sharp edge against my head, causing a red mark and a little discomfort. As the harness is not spring loaded (unlike Rift CV1 and Valve Index) it requires the rear harness to be loosened, and the headset pulled over the head before tightening.
After removing the headset, I noticed a slightly sharp plastic edge at the base of the battery bay, where the cushion wasn’t fitted quite square, but had rotated a little relative to the plastic molding behind it.
After removing the headset and repositioning the cushion, this problem wasn’t noticed again, though Pimax may want to put a gentle radius along that plastic edge to make it less prone to causing user discomfort if the cushion has moved.
The shape of the cushion could also benefit from some further development, as I found the flat shape of the cushion didn’t properly support my occipital bone (back of head) but had a small vertical gap causing the headset to move around at the rear a little.
Something easy to experiment with in the future thanks to the Velcro cushion fitting, making it very easy to fit an alternative cushion with a more appropriate shape to suit my occipital fit.
Top Strap
What looks like the top strap of the headset harness is actually a thick rubber “power strap” connecting the rear battery module to the front compute unit, this makes adjusting the actual top strap (hiding underneath) a little difficult.
The actual top strap is a stretchy, elasticated style fabric piece, with Velcro-faced tab adjustments at either end to allow tightening or loosening as required.
The top strap is a bit underwhelming, considering the bulk of the headset, and the adjustment tabs are quite short, making the on-headset adjustment a bit fiddly as the actual top strap itself is somewhat obscured by the power strap sat above it.
As with fitting many top-strap headsets, you need to prejudge where the headset is going to end up sitting on your head after it has sagged underweight, to maintain the correct vertical alignment with the lenses. It’s easiest to do this whilst wearing a headset, so that adjustment can be quickly optimized by adjusting and checking.
But with the thick power strap somewhat restricting access to the adjustments whilst the headset is being worn, it may be easier to remove the headset, set the strap length, refit the headset, test it, and make any further adjustments as required. Unless multiple people are sharing the headset it’s something you need to set up only once, so not a big hassle.
Sound
My Crystal shipped with Pimax’s top-of-the-line DMAS speakers, these use a very similar BMR (balanced mode radiator) 40mm driver to Valve Index, with both drivers being made by Tectonic who is a specialist in the BMR field.
The DMAS speakers are simple to fit and come from the earlier 8K Reality series, hence the blue color of the mounting puck. The speaker volume can be controlled using the volume adjusters on the right top face of the headset, behind the power button.
The only time I needed to remove the speaker (right) was to remove the DP repeater/extension cable box from the head strap, otherwise, they were left in place and did a good job with all the benefits of off-ear audio which once you have tried, may find hard to go back to wearing over-ear cans.
In terms of adjustment, the speakers can rotate around a fixed pivot, and have a sliding mechanism to provide some height adjustment; meaning I could set the speakers at just the right height for my ears. Despite BMR speakers being more tolerant of misplacement than using normal on-ear speaker drivers, there is still a sweet spot for BMR driver placement to get the best sound quality, making it important to get your ears and speakers aligned.
When fitted correctly, this audio system has a good sound quality with plenty of detail and strong bass reproduction. Certified for DTS-Audio, the DMAS speaker system should provide good reproduction of music, dialogue, and sound effects for watching movies, as well as playing your favorite VR games.
Controllers
The Crystal’s motion controllers looked neat, though rather generic. However, these new controllers are really important for Pimax so they can provide fully featured controllers with a joystick, extra input buttons, and finger tracking. This wasn’t possible for the Sword controllers which relied on the old SteamVR driver for the HTC Vive controller, with its limited input options and lack of support for analog joysticks.
The Crystal controllers are surprisingly small, each one weighing only 130 grams. They feature a small joystick, X and Y buttons, Menu and Pimax buttons, side grip buttons, and frontal triggers. Rechargeable batteries inside the controller with a USB-C charging socket at the base of the grips allow for the controllers to work.
The hardware for hand tracking is already incorporated, though wasn’t activated at the time I started testing the system, coming soon as part of ongoing software updates.
In terms of function, they felt adequate, but in terms of fit a little too small for my medium-sized hands finding the side of my thumbs catching the inside of the tracking ring when moving the joystick left (left controller) or right (right controller).
This is not painful, but perhaps uncomfortable during a longer session, something I could explore in the future with more gaming time.
Weight Matters
Let’s get the elephant in the room out of the corner, into the limelight, and talk about weight. I’m not hiding from this, it is a physically large, and relatively heavy headset. It has been reported as being nearly 1.2kg, but I wanted to directly find out how this might impact the overall experience.
Crystal is physically large because it shares the same external casing as the forthcoming 12K, despite having a more regular field of view. The reason for sharing many components (including the external casing) is to make the two products more cost-effective to manufacture and develop, otherwise, it would require two product lines of unique parts and two software development projects.
From watching a recent interview with Pimax’s CEO Nordic Ren, I understood that Crystal is the first stage of their “12K QLED platform”, followed by 12K, and then further systems in the future.
As a dual-mode, inside-out tracked headset, Crystal also contains four cameras, onboard compute and memory, the external battery (120g) with its mounting hardware and power strap, a small internal hot-swap battery, tether mounting hardware, 100g of replaceable glass lenses with eye tracking hardware, and off-ear speaker pods. You can see how it quickly adds up in terms of weight.
Earlier Pimax headsets like the 8K line, and the forthcoming 12K, are known for their huge lenses which provide the ultra-wide field of view that Pimax is famous for. Crystal lenses are much smaller (regular size) than the 8K and 12K lenses, hence the large gap seen on either side, as shown in the image above.
I put the Crystal headset on my digital kitchen scales and it registered 1160g, this included the battery and tether attached (but laid flat on the counter). In comparison, my Index weighed in at 791g including a 3D printed wide face gasket, VR Cover for the rear head strap, and tether attached (also laid flat on the counter).
The 369g weight difference is easy to account for considering the Crystal’s glass lenses (+100g), external battery pack (+120g) and extra compute. It indicates that whilst the Crystal has a big casing, that big casing is not particularly heavy in itself, maybe.
Putting the Crystal on my head was revealing though, with a good front-to-rear weight distribution helping to center the headset on my head. The rear battery (120 g) and associated mounting hardware were doing a good job in balancing the headset, similar to using inert mass (coins, weights) strapped to the back of other headsets to take the weight off the face.
Something to be aware of though, with increased mass comes an increase in inertia, making an unwelcome presence felt when quickly turning. This can cause the headset to move about on the head with implications for maintaining eyeball alignment as well as motion tracking.
I tightened the headset strap as far as comfortably possible and moved my head about, confirming my suspicion about inertia: there was a tendency to move about independently of my head, with a slight lag as the headset accelerated. This is something I’d also experienced in my Index during really fast games, though to a far lesser degree, a combination of the better fit and lighter weight.
Cranking the rear strap down helped, but at the expense of extra pressure on the face, and still not addressing the underlying issue I probably needed a slightly narrower face cushion to help secure the headset in place and minimize any movement which was being exaggerated by the heavier weight.
Some Pimax Crystal users online have reported using after-market face cushions from different headsets to solve fitting issues, or using weatherstrip foam under the sides of the cushion, so this is something to explore later on.
Due to the weight of Crystal, the headset may also benefit from a thicker, wider head strap to provide more support and stop it from sagging so much. I’ve already seen posts on Reddit with users modifying the Crystal with after-market straps and strap comfort mods to improve fit and stability.
Installation
Pimax has a new software client: it was easy to download, install, and start running on my Windows 10 PC. Once installed, the headset is connected, or so I assumed. Not to hide anything, but initially, there were some issues trying to connect my Crystal to the PC using the fiber optic cable supplied with the system.
After reaching out to Pimax support, they suggested trying the copper cable that I had received as a spare with the headset. This seemed to improve things, though the connection was still hit and miss, sometimes taking numerous restarts to get the headset recognized just once.
I then tried reinstalling the Pimax client, updating all drivers, reinstalling my Steam installation, and even reinstalling my Windows 10 operating system to get things working by ensuring all PC software was on the latest version. Despite all this, a reliable connection continued to be elusive; I tried using my Valve Index on the same PC and had no issues making the connection, during long PCVR sessions or hooking up multiple Vive trackers for FBT.
After further contact with support, the suggestion was to bypass the DP repeater/extension cable loop on the side of the headset by plugging the tether straight into the headset. This involved unclipping the face cushion and plastic base, removing the left DMAS speaker, and carefully extracting several tiny metal screws.
With the DP repeater box removed, and the copper cable plugged straight into the headset, it connected the first time, and we were off!
However, one concern, as it is something that plagued the Index from launch, is the repeated bending of the tether where it exits the headset connector. I’m assuming this is why Pimax had the extension loop cable originally fitted, which like the Vive Pro, prevents bending damage to the tether.
With this extension now removed, it was obvious that repeated opening and closing of the headset whilst putting on and taking off, was starting to crease the tether. For now, I would keep an eye on this area, as it required the replacement of my Index headset only two weeks after launch when repeated bending and creasing started causing sparkling video in the headset.
After connecting the headset, I started Steam VR and entered a strange version of Steam Home; I seemed to be under the floor, as the headset was having trouble finding the floor level.
I restarted the headset and now I appeared on the roof above the Steam home, looking down through a window at the game selection menu far below. I ran the room setup tool in Pimax Client again, but then found myself high above the Steam Home house, looking far off into the mountains which demonstrated the high PPD very clearly.
Using FPSVR, I quickly made a manual adjustment to floor height, which forced the headset to use my determined ground level as a reference. With the headset now connecting and ground level established, I wanted to check the field of view that was visible in my headset.
FOV check
Headsets have a maximum rendered field of view, but often considerably show less, accounting for differences in human physiology. How well does your face fit into the supplied cushion? Does the harness support your head shape correctly? Does your vision work well with the lens design? Is there any eye relief adjustment? Can the headset angle be tilted? What effect do different IPD settings have on the field of view?
The maximum rendered field of view can be obtained using tools that ask the headset driver for the information, but after having obtained that information, I was interested in what I could see for myself.
I used developer Boll’s excellent “Wimfov” tool (https://boll.itch.io/wimfov) which allows the user to determine what can be seen in each eye by adjusting 16 light ray sliders, providing an accurate result unique to each user and their headset fitting. This will provide accuracy to within a degree giving a useful and relevant result.
Using the comfort face cushion and tightening the Crystal as firm as possible to stop any unwanted movement, I ran the tool (wearing the headset whilst using a keyboard) and got the results as seen below in the image showing the output into a web browser at the end of the test session.
Stereo overlap was a useful 74%, whilst the “shape” of the FOV was a big square with rounded corners, making it feel more generous than the numbers. The optical clarity of the glass lenses also seemed to make the FOV seem more “open” than many Fresnel lens-based headsets.
The comparison was then made with my Valve Index (fitted with 3D Printed wide face cushion), using the same tool provided the results seen in the image above, a touch more stereo overlap. Index’s FOV looked different to Crystal with a rounded shape, and less clarity across its dual-compound plastic lens, though I always considered Index’s geometric stability class leading.
Stereo overlap was similar between the two headsets; both provide a convincing stereo image so important for VR. Going back to Index was interesting, with noticeable glare in brighter scenes making the lens clarity seem slightly obscured or greasy, like the lenses needing cleaning. I also started to notice a slight screen door effect on Index which I hadn’t really seen it much before, although this soon disappeared when busy in a good game (exciting stuff)!
First Experience
Satisfied with my FOV check, I started one of my favorite applications, “Aircar”, which is built on Unreal Engine and always looks great at higher resolutions. As I’d had some issues getting Crystal’s motion controllers to connect, and stay connected (these were the early days) I decided to use my Xbox wireless controller, which handily is my favorite controller for this game.
Aircar has centering controls built-in, so it was very easy to get myself in just the right position to suit the in-game cockpit. Starting in the garage as always, I flew forward and came to a pause whilst hovering outside the garage, to go into a menu to adjust the visuals in-game.
I set everything to maximum whilst maintaining an in-game render resolution of 1.0, with SteamVR reporting a headset resolution of 100% as 4312 x 5100 per eye. Skarredghost later told me this was sort of 4K per eye, take that Apple 😉
At this point, my PCVR rig with its 3080Ti spun its cooling fans up to a maximum, starting to struggle with the ridiculous rendering workload. My PC sits on a wheeled trolley in the corridor outside my VR room with the tether cleanly passing under the door, despite the door being firmly shut it sounded like a jet engine was running on the other side.
I was getting 45-50 fps but the visuals were shocking, absolutely stunning with huge levels of detail and a super clear picture down to the street level. Despite having good VR legs, I reduced the headset resolution to 70%, which provided a more comfortable 90 fps, whilst still looking very sharp and highly detailed. Immediate thought, just wow!
During a couple of seated sessions in Aircar and Project Cars 2, I started to notice headset instability, which didn’t seem to be caused by the optical tracking, perhaps a faulty IMU, causing my Aircar to sometimes pitch forward, start rolling even when game paused, it was quite random.
This continued to be an issue in several games as well as in Steam Home. After some discussion with Pimax they agreed to replace my headset. Bearing in mind this was a pre-production sample, without a technician inspecting the headset it was difficult to tell what had happened, though the large box had taken a pretty hard blow during shipping, perhaps damaging something inside…
I offered to send the first headset back, but they advised me that a replacement was on the way, and to retain the first headset until things were resolved. Top marks to Pimax for its excellent customer service!
Second headset
The second headset arrived after just a week and came in a differently shaped box, things were also laid out differently with a thick foam rubber spacer wrapped around the front of the headset strap, to prevent shipping damage to the plastic clip that the top strap mounts onto.
Once again, the headset box contained a thin fiber optic tether cable, but this time the comfort face cushion was already fitted, the thinner cushion spare in the box. The most interesting thing I found bundled with the new headset was a USB hub designed to provide support to the battery through the USB lanes of the tether.
Second Experience
Now that I had the second headset with its USB hub, it was time to restart my testing. For a short while, I was the proud owner of two Crystal headsets, so of course I had to take a photograph for posterity.
Out of the box, I had similar connection problems to the first headset, whilst using the supplied fiber optic cable. Pimax had advised me to retain the copper tether cable (which had come spare with the first headset), so this was the first item to be swapped out.
After trying to get a stable connection (it took several restarts to finally connect) I then removed the DP repeater and cable extension loop from the left side. This was much easier having done this before, and it quickly came free, letting me plug the tether straight into the headset connection.
With the DP repeater and extension cable now removed, I finally enjoyed a hassle-free connection each time. Later on, I tried fitting the USB hub, but started experiencing intermittent connection problems: the hub seemed to be causing an unstable connection on the USB side.
The hub was swiftly removed, and the connection was once again stable. However, this was at a cost of no battery support through USB, and the slight reduction in mobility and reach from using the thicker and shorter copper tether cable rather than the fiber optic version. Other Pimax Crystal users on Reddit mentioned their success using after-market powered USB hubs, which is something I could purchase at a later date.
During this time, there had been several firmware updates for both the headset and controllers. Finally, the controllers started to connect every time and there were general improvements in controller tracking, though still a bit glitchy and less precise than is necessary for fast gaming.
With the headset now connecting each session, I could finally spend my time adjusting the fit to get the optical alignment just right. It soon became obvious that the lenses have a sweet spot (optimum alignment relative to eyeballs) that is easy to set in the wrong place due to the high clarity of the lens. With older Fresnel lens-based headsets it’s quite easy to tell when the lenses are misaligned as you are rewarded with an eyeful of glare or god rays.
Overall the headset setup took some practice as it is very eye position dependant; this is unique to each individual’s craniofacial fit making it difficult for headset manufacturers to accommodate everyone within their design. Lacking the spring-loaded headset harness of the Index, Crystal had to be loosened on removal, and tightened for each fitting, introducing the possibility of slight misalignment which is more noticeable in high-resolution headsets.
Getting the best fit possible using the comfortable face cushion, and looking around inside the lens, I experienced distortion around the outer perimeter of the lens; during some different games, I started feeling the pupil swim.
I also saw chromatic aberration in some different situations: the Steam VR menus showed slight color fringing around the edges, whilst Wevr’s “The Blue” had an intense blue ring around the outside of the lenses. The amount of distortion seems to vary slightly depending on the game engine, Project Cars 2 (Madness), Valve’s The Lab (Source 2 and Unity), and Aircar (Unreal) all present things differently.
I tried adjusting the IPD to see if this would help, but the distortion seemed equally spaced around the perimeter of each lens, perhaps indicating my eyeballs had the correct X, and Y alignment relative to each lens centre.
Removing the face cushion entirely and pushing the headset against my face was revealing as there was a noticeable reduction in distortion, my first thought was that my eyes needed to be closer to the lenses to get the best fit. Without mechanical eye relief adjustment (Z axis) the only solution was to change the face cushion, although thin face cushions are generally not comfortable to use with heavier or firmly clamped VR headsets during longer sessions.
An immediate and very practical solution was to avoid looking across the lens, by looking predominantly forward or going old school using my head to look around a scene. After several sessions this quickly became second nature, minimizing any visible distortion, which kept my eyes much more comfortable as swimming is best kept for water.
By the end of this preview, I was already experimenting with after-market face cushions, which showed a benefit in reducing-edge distortion and chromatic aberrations; something to further explore in the second part of this article.
PCVR Preview conclusion
During my testing, by the time the second headset had arrived, several software updates had been rolled out which made genuine improvements to connection and tracking. Updates to the controllers let me start playing room-scale games, though the headset itself still struggled to set floor level, also reported by other users.
Pimax suggested using OVR Advanced Settings (free on Steam) as an interim measure to set floor height, which certainly worked for each session, I also found the center marker to be very useful for room orientation.
The Clarity
Something that became undeniably obvious during early testing, and throughout my testing, was that their claims about clarity and resolution were not unfounded – this was a seriously impressive visual experience! I won’t mention the screen door effect as I never saw any…
The wealth of detail whether up close, or looking far into the distance, was breathtaking.
Aircar demonstrated Crystal’s sheer clarity and resolving power, I’d never seen the city in such rich detail, especially from height. Being able to look from height and see individual vehicles moving at street level, colors popped with vibrancy, blacks were near black and not the greyish soup typical of LCD; metallic objects had highly reflective sheens, and contrast and brightness were very impressive.
Driving in Project Cars 2, I was stunned by the quality and vibrancy of the world outside the cockpit, it was an incredible spectacle, showing rich details I had never seen before, despite hours of racing open seater cars in my Valve Index.
My smartphone camera had trouble focusing, so I used video mode and extracted single frames, and some are visible in the image seen above.
Valve’s The Lab looked super realistic, it was already a treat in Index with supersampling and high frame rates, but the considerably higher resolution of Crystal combined with the vibrant colors and deep blacks make it feel like a fresh experience all over again. Valve’s software optimization chops show through with a smooth comfortable 90Hz even at the higher resolution.
I still experienced some controller tracking issues, though typing using the SteamVR keyboard was possible, and selecting the volume control or other menu functions was much improved compared to the controllers used with my first headset.
The audio was of good quality from the off-ear speakers, providing a thumping soundtrack to many games, the microphone had a good quality of speech with no clipping. As with the Valve Index, some adjustment of depth (speaker-to-ear distance) for the off-ear speakers would be useful for people with noticeable asymmetry.
Headset tracking seemed competent once set up, similar to Windows WMR or Rift S headsets which is a compliment to those in the know. As with other inside-out tracking systems, it benefits from having some furniture, objects, or artwork on the walls of your room, to give the SLAM tracking something to lock onto.
Controller actions like using the bow in “In Death”, two-handed weapons in “Pavlov” or taking the controller out of camera range expose the Achilles heel of inside-out tracking. It’s nothing specific to Pimax’s iteration as it’s something I’ve experienced using other inside-out tracked systems including WMR, Meta Rift S, and Quest.
I still use the lighthouse tracking after seven years of PCVR, with three 2.0 base stations providing room-scale coverage with highly accurate controller tracking and no compromise of gaming style.
Games like In Death hugely benefit from being able to freely use the bow in all directions; whilst being able to lie prone on the floor in Pavlov whilst operating a heavy machine gun is always very enjoyable.
Pimax has offered to send me a Lighthouse faceplate as soon as it’s available, which would marry the best of both worlds, a Crystal clear 35 PPD headset with precision lighthouse tracking; I look forward to seeing this product.
With new software updates bringing further improvements, Crystal will only get better with time: one important update will be the Pimax stand-alone mode which I look forward to exploring later this year. Very interesting to see how that all works, and which titles will be available on the Pimax store.
Another big change will be the introduction of eye tracking; using the Tobii eye tracking system which operates at 120hz, a threshold for accurate eye tracking on PCVR. Once implemented it should be possible to set up the IPD automatically and run dynamic foveated rendering which has substantial performance gains for demanding simulation titles (or users without top-end GPUs) as well as removing distortions and chromatic aberration to improve optical comfort.
Bear in mind the pupil can move up to 3mm during full range of vision, which has obvious implications for VR headset optical setup, high-resolution headsets like the Pimax Crystal will show immediate and noticeable benefits from eye tracking technology. Welcome to the future!
Many thanks to Daisy and the team at Pimax for making this preview possible! Thank you to the Skarredghost for hosting my article, thanks to Sara Ramos for taking pictures, and thanks to you the reader for taking the time to read through this introduction to Pimax Crystal.
Rob Cole
(Header image by R.Cole, S.Ramos)