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RBE effect and my new HC3800 - Please advise

post #1 of 17
7/28/10 at 5:39pm
Thread Starter 
I've had my first projector - a new HC3800 from VisualApex - about a week now. Yes, I should have found out, but I am just now discovering that I am very sensitive to the rainbow effect and it's making me sick.

Since I'm a projector newbie, I wonder if people here could answer any of these questions I have about the RBE.
  1. Is it typical for a person who is sensitive to the RBE to feel dizzy to the point of sickness?
  2. Does the framerate of the media matter for reducing the effect, and if so, is it possible for the 3800 to accept a 48 frames per second signal instead of 24? Is 48hz unheard of?
  3. Does it matter that I'm displaying this against a white wall instead of a screen?
  4. Are there any other ways I could reduce the effect?

I just read through the post here (can't post urls yet, but it's thread 815451) and it sounds like the only way to deal RBE is to reduce contrast by ambient light or other means. Maybe I misunderstand but that doesn't sound like an appealing solution at all!

If I can't acceptably minimize the effect, I'll probably return the 3800 and purchase a 3LCD projector in its place, such as an Epson 8100. However, from what I've read, the sharpness, contrast, and brightness (in best mode) of that projector and all other 3LCD projectors in the $1000-$2000 price range is not nearly as good as the HC3800. In addition, I've read about many technical problems cropping up with the 8100, such as misaligned panels and bulbs dying early. I know the Panny 4000 is supposed to be good, but that may be more than I wish to spend, and I hear that it isn't particularly bright (which matters a lot to me).

I beg for any advise
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post #2 of 17
7/28/10 at 5:43pm
If you are not already, try the setting the lamp to eco or low mode over bright images tend to cause rainbow more or so I have read. I have never seen one with my DLP HC3000.
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post #3 of 17
7/28/10 at 5:49pm
Thread Starter 
The thing is, I strongly prefer a very bright picture (and it doesn't seem particularly bright as it is).
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post #4 of 17
7/28/10 at 6:23pm
Are you sending it a 24Hz signal instead of a 60Hz signal? The wheel does spin slower at 24Hz and the slower the wheel spins the more chance of RBE.

I'm lucky enough to not see any RBE and mine is pretty bright, but some peole who are VERY RBE sensitive can get dizzy and nauseous. If you are so RBE sensitive that you get sick, then you may need an LCD.
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post #5 of 17
7/28/10 at 7:55pm
Thread Starter 
Yes, I am using a 24Hz signal. Originally, my computer was pushing out a 60Hz signal, but I researched how to get 24Hz to eliminate 3:2 pulldown. I figure a 48Hz signal would be ideal, but I don't know if that's possible on either end. I'm guessing no.

I've only watched a few films on it so far, so I'm still getting a gauge of how sick the RBE makes me (the first time I got sick I sat too close). Apart from dizziness / mild nausea, it can be distracting visually.

If I go the route of getting an LCD projector, can anyone advise on which model to go for in the $1000 - $2000 price range?
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post #6 of 17
7/29/10 at 4:06am
Are your seeing rain bows?


Your description sounds more like to close and to large of an image stuff?
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post #7 of 17
7/29/10 at 8:38am
I do see it in my hc3800 but does not make me sick. Try Epson 8100 LCD for about the same price, but with less "pop" and slightly less sharp. However, I do not recall light spill in the Epson.

Epson's quality and the hc3800 is about the same, pot luck. Bear in mind that even high price PJs also have quality issues. In the end, you do want to consider warranty and customer service support as part of the overall valude decision, as well as the vendor. VA is fine.
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post #8 of 17
7/29/10 at 9:03am
Since this is your first PJ, I would suggest swapping for the Epson or similar LCD. It will still look great when installed and you're watching it. I have a DLP and quite happy not to suffer from RBE. But if it was an issue, I'd switch and be happy. Remember, when folks are comparing these new PJs, the differences aren't that great. Nearly all show a great image. It's not worth enduring headaches and nausea in hopes that you eventually get used to it, the lamp dims enough to notice it less, or worry that the return window has closed before realizing that you need LCD.
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post #9 of 17
7/29/10 at 10:49am
Thread Starter 
Thanks for the advise, guys. I just called up Visual Apex to do an RMA. Since I have more than 5 hours on the unit, I was told I will need to wait for approval from a supervisor. I didn't understand that there was a 5 hour usage return limit when I first bought the thing; their return policy is worded very ambiguously for a first-time buyer like myself who doesn't know projectors track usage times.

The representative at Visual Apex was quite friendly, but I'm bothered that I will have to pay a 15% restocking fee, especially since I'm willing to commit to repurchasing a different projector from them. I'll be out $200, which wouldn't be the case had I bought from Amazon or CostCo.

Return hassles aside, I think I will go for the Epson 8100 once the return gets taken care of.
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post #10 of 17
7/29/10 at 11:13am
Good luck. Check the 8100 thread for potential issues and check it carefully when you receive it. Swap until you are happy. Then enjoy.
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post #11 of 17
8/2/10 at 1:06pm
blorgo,

You could be of the unlucky few that are very sensitive to RBE, and in that case, there isn't much you can do but avoid DLP.

That being said, RBE will be less if you send the HC3800 60hz (as mentioned) and stay away from 24fps.

Also, sitting further away from the screen helps also. I sit 1.5x screen width away, which is about as close as I want to be when playing DVD's (not blu's).

Brightness> The larger the screen (assuming same gain), the less RBE, due to the dimmer image you get going larger.

New lamp> For some, the brightness of a new lamp (new PJ) can induce RBE, and as the lamp ages (gets dimmer), RBE can fade away.

But again, it could be you are Very sensitive, and in that case, even under the best circumstances, DLP may not be for you.
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post #12 of 17
8/3/10 at 6:58am
If you are really bothered by RBE and are willing to spend up to $2K for a different technology then you could consider the Panasonic AE4000 (just under $2K). It has better contrast, lower black levels and far more features than the Epson 8100. The higher-end Epson model 8500UB provides even better black levels than the Panasonic. It normally sells for around $2.5K but VA now has it on sale at a really good price, so I would probably go that route as it is a top rated projector in the under $3K price range.
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post #13 of 17
8/3/10 at 8:08am
Quote:
Originally Posted by blorgo View Post


Is it typical for a person who is sensitive to the RBE to feel dizzy to the point of sickness?

I don't think so but i'm not a medical specialist. Do you suffer from epilepsy?
Quote:


Does the framerate of the media matter for reducing the effect, and if so, is it possible for the 3800 to accept a 48 frames per second signal instead of 24? Is 48hz unheard of?

Na, sorry dude, won't work. The color wheel spins at a certain speed no matter what.
Quote:


Does it matter that I'm displaying this against a white wall instead of a screen?

Shouldn't matter
Quote:


Are there any other ways I could reduce the effect?

I would return it while you can and get an LCD.
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post #14 of 17
8/3/10 at 8:10am
Quote:
Originally Posted by Legairre View Post

Are you sending it a 24Hz signal instead of a 60Hz signal? The wheel does spin slower at 24Hz and the slower the wheel spins the more chance of RBE.

Do you have a link explaining this... I was never under the impression that the color wheel varied it's speed based on the input.
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post #15 of 17
8/3/10 at 8:57am
Quote:
Originally Posted by Verge2 View Post

Do you have a link explaining this... I was never under the impression that the color wheel varied it's speed based on the input.

You can hear the wheel slow down when going from 60 to 24Hz, but here's a few links that discuss the wheel slowing down at 24Hz.

Scroll down to The color wheel "rainbow effect"
http://en.wikipedia.org/wiki/Digital_Light_Processing

Search these for 24Hz
http://www.avsforum.com/avs-vb/archi...t-1151980.html
http://www.avforums.com/forums/proje...heels-rbe.html
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post #16 of 17
8/3/10 at 10:11am
I can hear colour wheel slowing down, when switch from 60 Hz to 50 Hz on my Mitz HC-1500...
Quote:
Originally Posted by Verge2 View Post

Do you have a link explaining this...

http://en.wikipedia.org/wiki/Digital_Light_Processing
"...The effect varies with the rotational speed of the color wheel and the frame refresh rate of the video signal. There is a maximum rotational speed limit for the wheel, typically 10,000 to 15,000 RPM. Video framerate is usually measured in frames per second and must be multiplied by 60 to find the wheel speed, whereas 60 frames/sec equals 3,600 frames/minute. If the color wheel spins 4 times per frame, it is rotating at a speed of 14,400 RPM. (Projector specifications often list the wheel speed at specific framerates as 2x, 3x, 4x, etc.)... Increasing the video refresh rate to 85 frames per second does not necessarily further reduce the rainbow effect since this rate would increase the wheel speed to 20,400 RPM, potentially exceeding the safe limits of wheel rotation and requiring the projector to drop back to 3x speed, at 15,300 RPM....".
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post #17 of 17
8/3/10 at 10:15am
Quote:
Originally Posted by Legairre View Post

You can hear the wheel slow down when going from 60 to 24Hz, but here's a few links that discuss the wheel slowing down at 24Hz.

@Verge2

http://archive2.avsforum.com/avs-vb/...pm#post9077014 (post #51)

http://www.cine4home.de/knowhow/DLP-...Farbraeder.htm (you will have to use google translate for this one)


At 24fps it actually slows the color wheel down to 48hz (double 24) to sync. So the difference is 60hz vs 48hz sync rate....not huge, but it can/might make a difference to some who are RBE sensitive (and I guess the reason why they double the 24hz refresh rate to 48hz on DLP's):

60hz x 4 (cw speed) = 240 RGB refreshes
48hz x 4 CW speed = 192 RGB refreshes

On single chip DLP's, the CW has to sync with the incoming input signal (though 24hz input is actually doubled to 48hz).

So yeah, keep it at 60hz if you're RBE sensitive.
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