I just received my 8kx and can't get the optics right (solved with ipd hardware mod)

Part of the issue I found was the angle at which the headset sits on your brow, I too had blurred text outside of the center view of the lens, looking slightly left or right introduced mura that made text uncomfortable to read. You need to get the lense perpendicular to your eyes. I solved this by adding some additional padding under the lower side of the cushion.

After that I re-jigged the PPD slightly I hooked up the eye tracking which then worked (it was off-center previously).

All I can do is recommend you experiment with repositioning it on your face until you find out where it feels correct.


I just got my 8KX. I had a problem with focusing: I also saw potential, but something was wrong. Sweet spot was really small, and because of that, keeping stuff in focus was very difficult. I never had this problem with 5K+. So, I just replaced the default 8KX 11 mm foam with 15 mm foam from 5K+. And immediately, magic was back! Huge sweet spot, effortlessly perfect sharp image. I’m wearing glasses, maybe this is a case, but anyway, thicker foam completely solved this problem for me. I ordered 8KX 15 mm foam already. But so far, even with 5K+ 15 mm foam, I couldn’t be happier with my new 8KX.


Does anybody know what the focal place of the 8KX is, i.e. which distance the eyes believe the screens are in ? Obviously we don’t have proper vari-focal headsets yet, and the 8KX isn’t one either. ANd as obviously the physical distance of the eyes to the displays, which will be approx. 3-6 cm, is not what the eye (better: brain) believes it is looking at - because the lenses bend the light in a way which lets our eyes see it at a different distance. It likely is somewhere in the range of 1-3 m. Does anybody know the value for the 8KX ?

This information is important for anybody who is short- or far-sighted and is considering getting lenses/glasses to adjust his sights for the 8KX. The reading glasses a far-sighted person uses won’t work as well as you might think, because they are measured to allow you reading at a shorter distance, say 50 cm. The values for 1 m or 3 m will be different again.

I am currently using my PC reading glasses, which I don’t like for reading books, but which work well at 1 m distance. And they certainly improve my acuity and also lessen the cross-eyed experience I have with the 8KX. Which may mean that the cross-eyed sensation is due to not being able to properly focus on the focal plane of the 8KX.

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For completeness sake I tried with a 22mm thick foam instead of 11mm last night (and any step in between). For me it was terrible, truly terrible. Like when you take the headset off and you look at the lenses. You’re just not there anymore at all and the the far sides which are usually completely ‘just distorted’ now completely dissappear, leaving only an almost single ocular vision area visible in the center. (which is much smaller than e.g reverb g2)

I believe that you and others experience an improvement with more distance. I theorize that if you have the required minimum IPD on your eyes (=personal) and you go too close you are in fact moving out of the focal point of the 2 combined lenses too much. Creating slightly more distance would solve that in your case.

For me it’s quite the opposite since I don’t have the required minimum IPD: Every test so far shows the closer the better for me as the sides become more visible and immersion increases as well with general clarity at the cost of being even slightly smaller IPD relative to the lenses. But 1 thing is for sure: at any distance whether it be 11mm or 22mm I can never get both eyes in focus of their respective lense center at the same time. Only 1 at a time each depending on where (left or right) I slightly shift the headset. So once more I’m full circle back at my first findings and the brutal choice of sending it back or going for the extreme IPD mod. I’m not able to use it in its current state.

In addition after taking off the casket and inspecting the lenses it’s become clear to me why. Clearly Pimax’ solution in order to generate a larger FOV was to physically increase the lense’s size but in doing so they also shifted the centers of each lense much more away from each other than corresponds with the average IPD of people, making it incompatible with almost the entire ‘lower half’ of IPD people out there. That explains the many comments about this.

Even now the lenses are already very close to each other but they’re just too big. Imho this is a design flaw: They should have either settled for a smaller maximum FOV (150 instead of 170 works just as well as the last bit is unusable anyway) in order to respect the maximum allowed IPD or they should have completely redesigned the lenses to have their focal point shifted toward the middle instead of their centers. Or should I say even more if this is already the case. In addition if their goal was to min/max they should have also reworked the center connection between the lenses in order to allow them to touch almost and thus allow the hardware IPD function to go below 60. That would solve it for everyone, large or small IPD.


I’m not saying that what had worked for me, would work for everybody else. Clearly, it is not. If someone need additional info, my IPD 63 mm, I’m shortsighted, wearing -3 glasses. For me 11 mm foam is too thin, but 15 mm feels just right.


Were you able to correct your issues by using that Samsung Odyssey Plus foam?

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Yes, I think it’s better with the foam for me. Also more comfortable. And the IPD range where I see sharp seems to have increased a little, can now go up to ~64mm again. Proportions are also a little more realistic (less big). And I didn’t get dizzy last time I played. Could also be getting used to it though. It’s a little give and take, distortions are a little more now again at the outer edges. But I think I prefer this setting.
It would definitely help if Pimax would put different foams into the package, particularly for these lenses that are so dependent on perfect eye-lense distance (Introducing hardware side eye relief might be a really good idea for upcoming Pimax headsets).

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We’ve asked Pimax about this and haven’t gotten a proper answer, as far as I know. There was a reply, but it was incorrect (~6 cm) which is the distance to the lenses, when what we want to know is the “focal distance”. To me, it seems like it’s in the range of 0.75 to 1.5 m.


Yes - “Virtual”, or “Apparent”, focal distance, or whatever one might distinguish it by. :7

…those six-ish centimetres for the absolute, technical, correct answer, sound way too much, though, by the way, to my mind… At least neither observer or subject is placed at that distance, in the HMD,.

I may be able to help here. As a result of cataract surgery I have artificial intra-ocular lenses (IOLs) in my eyes. With the type of IOL I have, you lose the ability to refocus your eye. So my two IOLs are set to different fixed focal distances in each eye (complicated story which I explained in another thread).

Anyway, by good fortune, my unaided left eye finds the 8KX display perfectly sharp, to the extent that the individual pixels are quite discernable. Since I cannot physically alter the focus of that eye, It therefore follows that whatever that eye is set to as a result of the surgery is pretty much the 8KX’s notional focal distance.

Taking the HMD off and measuring the distance from my left eye to my computer screen when the text on it is most in focus, I get 93cm. So that is the notional focal distance of my 8KX, give or take a centimetre or so.

I have no idea of how sensitive the focal distance is to manufacturing variations, or how consistent Pimax’s manufacturing is, so take my results as a guide only.


Hey Mate. No not at all. It was basically the same result as my self-made foam where I immediately I couldn’t see anything on the sides anymore and stuff became the opposite of immersed. Completely unusable.

After days of testing and trying I realized that unfortunately my first conclusion was the right one: The lenses are too far apart :frowning: and nothing will fix that except physical operations on the headset.

Since I now had to make the hard choice of sending it back (and losing alot of money anyway because customs import and transport) or going for the extreme mod and take a chance I went for the latter.

With the guidance of user Trigen (third replier in this thread) for the rough bits I took it slow over a few days and successfully did the mod as custom as I wanted: I can now actually make the lense frames completely touch using the slider (as in zero space left in the middle part) if I want to.

That solves the issue and the small sweetspot is now super sharp as it should be at the cost of horizontal fov becoming somewhat smaller, something I honestly don’t care about anyway.

I’m still left with finding the perfect new software ipd for my the new physical location of my lenses but by chance 2 days later my HP Reverb 2 unexpectedly arrived and the busy work/festivities period begun.

In hindsight I stick to the statement that Pimax should redesign this headset with the same display quality but smaller lenses and allow them to be moved much closer to each other as part of the default design, without requiring extreme mods. That should fix the optics for all sort of people faces and prevent us having to do this ourselves and void our warranty in order to make the product usable :frowning:

I hope they take a lesson here as I’m taking one for the team (=Pimax community)


Thanks for your turning your disadvantage into a superpower, taking and sharing your measurements. :slight_smile:

Now, the obvious next step, is for each of all of us here on the forum to also get IOL;s, at a range of assigned focal distances, turning us into a mighty distributed instrument, that can match up an eyeball with the per-unit optics of any particular HMD.

I see no weaknesses in this plan. :wink:

Hi All,
Yes, I’m in the same boat also. This is very frustrating as I have not been using the 8KX because this has been a problem for me that I have not been able to resolve, just as stated by others and put nicely into words by @Profundido. I have experienced the same as described in 3 and 4.

I recently go frustrated waiting for the DMAS and after getting a somewhat weak confirmation that it will be delayed until sometime after the CNY, I decided to take my Vive DAS off my Pimax 5K Plus and attach it to my Pimax 8KX and try finally using this thing again, I was pleasantly surprised with the improved sound compared to the SMAS, but then I was quickly reminded of the impossible visual issues.

My IPD is 63.5 Near and 65.6 Far / Segment Height: 24.9 Left and 22.0 Right.
I purchased Prescription Lenses from VRMUST.
I have tried everything, I was hoping that IPD Adjustment Tutorial that shows in the Menu and was mentioned by @SweViver was here to possibly assist as I am at a lost.

Same as described by @Profundido


Hi if you found the MAS worked save the bad sound.

Here are some options.


Thanks But I was trying to avoid going through the hassle of doing my own modifications with my 8KX, after all, I paid $1200 USD for this thing. But once I got the really bad news that the DMAS was being delayed again and the CNY was just around the corner, I just decided to Remove the DMAS from my 5K Plus, I already had the 3D Printed parts, it’s now attached to my 8KX and I don’t think I will every go back and change it unless there are reports that the DMAS is superior in Sound Quality to the DAS.

I get so sick of alway having to compensate for things when they have cost me so much money.

And I’m just too lazy to fiddle with this any more since now I have pretty good full bodied sound from the DAS.

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The SMAS is only intended as a place holder or for those whom are looking to either have really easy removal or use own headphones.

If you have ordered DMAS at time of 8kX it should be on par/similar to Index as it is said to be using the same bmr drivers.

There is a cool mod on reddit using cv1 headphones no 3dprinting that even uses the MAS’ headphone jacks.

I do have the kdmas of which with having Vive DAS can say is higher quality sound. Which of course with pimax now selling it for same price as SMAS. Imagine SMAS will be phased out as as predicted by the community was not well received.

This SMAS mod/addon by @Virtualmisterl has good reports.


I was reading your statement:

I am currently using the Vive DAS with a 3.5mm to USB-C Adaptor, Not a single 3.5 input on the HMD. In your opinion, Would you say that the KDMAS has better sound quality than the Vive DAS?

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Yes imho the kdmas sounds better. Is the headphone jack broken on the headset?

Hi @Heliosurge,
No, the headphone jack is not broken, I was just reading in one of the threads that you should not use a single input jack on the 8KX as it would not have the output power to really drive the headphones.

I ended up purchasing a 3.5mm to USB-C Adaptor that has a built in DAC and ADC which shows up in Windows as a DVD Quality Hi Res headphone.

It supports the following:

Smart DAC Chip

This Headphone Jack adapter is compatible with up to 32bits / 384kHz while others are 24bit/96Khz or 16bit/48Khz. High-fidelity noise reduction design, clear sound quality conversion, bringing you original sound quality.

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