My 8KX Review & Problem & Solution

My Pimax8KX has been arriving for a week now. There are some noticeable areas of completion, but I’m loving it so far. I probably won’t be going back to ValveINDEX.

I’ll give good and disappointing points. For me the good parts far outweigh the bad parts and I enjoy 8KX every day.

■Good point
1.Really high definition (SDE is still recognizable but hardly noticeable).
2.Better black levels against 8K (TheBlue’s deep sea is also very atmospheric)
3.Satisfied with the sound quality of the SMAS (but it leaks too much sound).
4.It runs smoothly at 75Hz (I loved the 144Hz on the INDEX, but the 8KX does feel at all fine).
5.I no longer need glasses (my eyesight is S=-2.0.
akes me a little out of focus, but I don’t need them anymore. It is the same as when I look at a real monitor from 50-60cm away with my naked eye).

■Disappointing point
1.The screen is dark and the saturation is low (a big disappointment compared to INDEX. I’m not satisfied with the current 0.5 unit adjustment. It makes me want to adjust the gamma curve more linearly).
2.The IPD is very difficult to adjust (this hasn’t changed since 8K. For me, the sweet spot is very narrow).
3.The shape of the face pads don’t fit my face.

■Points that may be a problem
1.The SMAS won’t go down
It came with plastic hinges.I don’t have any issues with the fit, but the speakers are too far away from my ears and need to be louder.

2.I need to turn it on and off twice or three times to normaly start 8KX
PiTool: the first time is a black and white screen.

3.I feel that the transmission performance of the lens has been reduced
Even in the sweet spot, the luminous intensity has been reduced in the surroundings and is yellowish in color.In the photo, there is only a slight color difference, but in reality, only the center is white and the surrounding area has a distinct yellow tint.

I would like to know if the above three points are normal or abnormal, and if so, if they are abnormal, whether they can be corrected.


This might be what you are looking for:

A janky 3d-printed add-on:

Other useful links:

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Totally agree with you on all points. The sweet spot is very small, I’ve ben playign with the IPD, I can get a bigger sweetspot by opening up the IPD but then it hurts my eyes, it’s almost like the software warping needs some tweeking???

I fitted the Vive DAS I have and it’s a million times better than the Pimax strap. I honestly feel that Pimax has gone backwards on the strap compared to the original 5k+ fabric strap, the new one is uncomfortable and everyone that has tried it has said the same thing. My Vive DAS also helps block out more light leaking in.


I have exaclty the same problems with my 8KX, do you have a leak lighting in the left panel on the bottom ?

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Thank you for your thoughtful help.

For me, the speaker volume of the SMAS is adequate.
The problem is that the hinges on the SMAS do not go down enough.

Since the speakers are far from my ears, I need turn up the volume and withstand the sound leakage.

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Thanks for the advice.

ViveDAS is very good. My ViveDAS is mounted on the 8K.
I will have to consider porting it.

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You can swap sides of the hinges, that brings it down significantly.

They offer to replace the plastic hinges with metal ones, if necessary. Seems like they altered the angle somehow.


I checked.
There doesn’t seem to be any light leaks.

I think the problem with the 8KX’s image being darker and changing color outside the sweet spot is due to the quality of the 8KX’s plastic lenses.

If you look at the lens from the sweet spot from the front, white is white.
But if you just move your gaze, the white becomes darker and tinted.

As the distance the light travels through the lens increases, the spectrum is absorbed and the color changes.

In light of the above, I cannot dismiss the possibility that a lens with low light transmission is being delivered that is not up to the level set by Pimax.


That probably good analysis of the lens problem. Hopefully they can improve over time as they’ve been known to do. If the eye tracker’s sole purpose is to help fix the color and distortion problems then I’m still ok with that.



My solution.
Eliminate the 8KX boot failure

I figured out the steps to turn the 8KX on correctly in one go.
Don’t start SteamVR until the device is fully activated.
Don’t even turn on the controller.

1.Press the power button on 8KX and wait until the Pimax logo appears on the HMD screen.
(If the logo fades out quickly or stays on the screen, you may notice it.

2.After that, start SteamVR and turn on the controller.

*)Discussion of the problem
If SteamVR starts up before the negotiation between the headset and the BaseStation has finished, the positional information will not be acquired correctly and the 8KX boot sequence will not end successfully.


My solution.
Adjusting IPD to provide a clearer picture

I got instructions and tips for adjusting the IPD in the thread below.

I’d like to describe the procedure.

As an assumption, I live with glasses adjusted at S=-2 (I have a bit of astigmatism, but I don’t have the correction in place).

I use 8KX with my naked eye. The image is much clearer than when I was looking through the original 8K with glasses.

The adjustment process consists of 4steps

  1. Adjusting the distance between the pupil and the lens
    Adjust the thickness of the facepad to find a distance where the vertical lines on the left and right side of the field of view are not distorted. I check this in VirtualDesktop (e.g. window borders). If you don’t adjust this part well, the distortion will haunt you for a long time after this. Make sure that your eye height is aligned with the center of the lens.

  2. Hardware IPD adjustment
    Put the real IPD value as it is.

  3. Software IPD Adjustment
    Move the IPD offset to both - and + to find the place where you feel the discomfort. In my case, I found the discomfort at -1 and +2. When I set the software IPD to 0.5, it looks more natural.

  4. Adjusting the vertical offset value
    This adjustment is even more important than the IPD adjustment. It is an adjustment to match the vertical eye position, angle, and normal eye use to your non-IPD facial features. In my case, once I found the right position, the overall clarity of the screen improved significantly.
    Display the text in the center of the screen in something like VetualDesktop and adjust the offset value so that this text is as clear as possible to read. This adjustment requires some patience.

In my case gave me the clearest image.
I can view a 3440x1440 wide monitor on VertualDesktop and read clearly to the edge of the screen with the naked eye.

Hardware IPD = 65
Software IPD = +0.5
Vertical offset = +2
*)The vertical offset value was initially +5.5, but after adjusting the height to cover the HMD, it settled at +2.

I recomend PiTool RQ is over 1 and SteamVR SS is over 100%.


The sound from the SMAS sounded horrible until I went into sound settings in windows and enqbked Sonic then checked Loudness equalization.

I also noticed that putting my hands over my ears how much better it sounded like 10x better.

Im going to try priniting these

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im thinking of printing these. How did it go?

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Do you mean that you do not need glasses compared to Valve Index, or compared to some other Pimax headset?

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…and if one is charging the controllers from any of the computer’s USB ports, make sure they really are off – one might want to unplug them anyway.

Otherwise, they will, I presume, already be considered “taken” (they will certainly show up in SteamVR), as wired devices, and not available to the tranceivers in the HMD. :7

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That’s right.
Vive -> VivePro -> Odessy+ -> 8K -> INDEX -> 8KX
I’ve ordered prescription lens adapters from VR lens labs and other sources for all models up to the INDEX, and I’ve installed and used them.

On the 8KX, I get a pretty clear image with the naked eye.


If so, then what you observe is an interesting finding, which so far no one else mentioned (as far as I am aware), and which would mean that the displays in 8kX (and therefore most likely in 8k+) are closer to the lenses (assuming we are dealing with the same lenses as in 5k).

Now, going onto a pure speculation, why Pimax would want to do that - one reason could be, they needed more space in the headset, the other reason could be the 4K displays they used in 8k+ and 8kX were smaller than the previous ones (I believe it has been even mentioned by Pimax) from 5k+ and 8k, and they did not want to lose the FOV so they put the panels closer to the lens to compensate for a smaller surface.

The consequence however would be that the virtual focal length gets smaller, possibly in the range where your impaired vision can notice the difference. With -2 dioptres you should be able to see clearly (without glasses) up to a half a meter, so it could indicate that 8kX virtual focal plane is (at most) around that mark.

Putting the displays closer, while keeping the same lenses, can however also impact the warping and other optical properties of the whole system, e.g. the size of the sweet spot (eye box).

I wonder if someone with similarly strong glasses could confirm the same experience. If confirmed, it could actually explain, why 8kX behaves differently than 5k+ and why it behaves so.


Although not knowing what -2.0 means, I can’t help but think that what you write here, adds circumstantial evidence to my loose hypothesis, that the 8k/5k series is designed by and for the nearsighted… :7


It actually suggests that 8kX is designed for even more nearsighted :wink:.


Maybe - I had the same problem with my 5k+, as did, I would have to presume, the whole “near IPD” crowd… :7

If Pimax have just shoved the screen closer to the lens in the 8kX, to fill out the FOV, or whatever, without considering the obvious consequences; Then I am at loss for words. :stuck_out_tongue: