JVC RS4500 (native 4K laser projector)

[Dylan Seeger]

As baseball0618 states, the only way to do dynamic contrast is through the dynamic laser dimming system. However, the manual aperture in the lens allows you to set a peak white of your liking and this will allow you to increase the native on/off contrast ratio of the projector which in turn will allow you to get a higher dynamic contrast ratio. Moving more towards the telephoto end of the lens (if your room allows for it) will help get even more contrast. Though none of this is new and most of us here realize how much projector setup changes contrast and lumen output performance.

[alangouger]

So the laser dimming is indeed as confirmed by Mike using an average multiplier between 5 to 6.

If using a higher mutiplier with a typical dynamic iris you may see some nasty artifacts, breathing etc. Having never seen Laser Dimming in action how does it compare to a dynamic iris, do you notice it, is it completly invissible,do you notice any artifacts.

Thank you!! 

[Dylan Seeger]

One thing that needs to be taken into consideration is that the projectors sold by JVC, Sony and Epson have much higher native contrast ratios than what you typically find in DLP projectors. This means that the dynamic contrast solution doesn't need to kick in until the APL gets lower than where a DLP projector would need to kick in. This typically means you're not going to see it working as much. I've also noticed that Sony, JVC and Epson seemed to have figured out how to use a 5-6x multiplier without the need to use as much dynamic gamma. Most of the DLP projectors that used a 3.5-4x multiplier seemed to use more dynamic gamma even though the contrast multiplier was less. This means less clipped whites and fewer artifacts associated with gamma shifts on these LCoS projectors.

The vast majority of DLP projector manufacturer's never seemed to figure out how to properly implement dynamic contrast.  Only Planar/Runco and Sim2 did to some extent, but they were dealing with relatively low native on/off contrast so their projectors often were plague with a lot of dynamic contrast artifacts such as clipping and visible gamma shifts.

[AVSCraig]

So the laser dimming is indeed as confirmed by Mike using an average multiplier between 5 to 6.

If using a higher mutiplier with a typical dynamic iris you may see some nasty artifacts, breathing etc. Having never seen Laser Dimming in action how does it compare to a dynamic iris, do you notice it, is it completly invissible,do you notice any artifacts.

Thank you!!

On my screen I don't  any artifacts in mode 1. Subjectively speaking, I watched Nova's " Black Hole Apocalypse " last night, and the many dark space scenes looked fantastic. The only artifact I could see was the " Nova " logo at lower right on the screen would occasionally dim - you can always find something. So minor as to be chalked up to " I see it because I'm a videophile specifically looking for it ". I'll try and shoot some screen shots of that show.  I used to prefer mode 2 dimming, but there were rare instances where it was over - aggressive. I've asked JVC to look into that and maybe ( hopefully ) do another software revision.

[Baseball0618]

So I just got word that my second RS4500, which replaced my first one that produced a random image judder, is also getting replaced b/c of a malfunctioning exhaust fan.    From the first day this unit was installed after the projector would warm up ( about 30-45 minutes) and the exhaust fan speed would increase to the next RPM level, the fan all the way to the left (looking at projector from lens side) would start to create this high pitch whistle that was so distracting.  I waited a few weeks before I brought it up to see if it would go away and it only got worse.    I emailed my dealer a video I took, he send it to JVC and they said they agreed that something wasn't right so they requested my dealer to take a log from the projector.   Presumably to see something that relates to the fan operation.  While my dealer was there he was able to hear in person the whistling to confirm I wasn't nuts and JVC looked at the log and confirmed that the unit needs to be replaced! 
   So I will be on RS4500 #3 in a week or two.  I told my dealer that JVC owes me some free stuff and they are lucky that I love the image this thing throws so much or most people would have probably thrown in the towel on it. 
   The funny thing about the whistle is it would go away if I switched into high laser increasing the fan speed, so it was only prevalent at the level it moves to after warm up in medium laser, which is all I use.

Here is the video on Youtube

[AVSCraig]

That's a bummer. Are they replacing them with brand new units ? If so, at least you have that going for you. Knock on wood I've have had zero issues with mine.

[Baseball0618]

That's a bummer. Are they replacing them with brand new units ? If so, at least you have that going for you. Knock on wood I've have had zero issues with mine.

Yes they are.  However the second unit I was kind of not sure on b/c it had 4 hours on it and it had the v1.22 firmware so I was thinking maybe it was demo'd or they checked it for the image judder the first unit had prior to shipping?  Oddly enough the serial number was one number higher than my first unit so right behind it in production. 

[AVSCraig]

4 hours is pretty close to brand new - maybe it was 4 hours of " quality assurance tests " !

[woofer]

So I just got word that my second RS4500, which replaced my first one that produced a random image judder, is also getting replaced b/c of a malfunctioning exhaust fan. 

I am also getting a replacement Z1/RS4500 in the next day or so...   JVC agreed to replace my unit due to a couple of ongoing issues.
My current unit has 460 hours on it, so will be starting over again..

JVC support has been superb...

[Baseball0618]

I am also getting a replacement Z1/RS4500 in the next day or so...   JVC agreed to replace my unit due to a couple of ongoing issues.
My current unit has 460 hours on it, so will be starting over again..

JVC support has been superb...

My first unit had ~ 800 hours on it and this one has ~ 500

I agree they are very responsive and if there is something wrong they address it.  Unlike Sony that hide behind vague fine print to avoid doing anything.  My 665es had a bad lens position memory where if you set an image position and saved it then move to another zoom position then back it would always over-correct ~1" in the direction of your last adjustment.  Sony rep came out and verified it was not working properly but Sony wouldn't cover it under warranty stating that it was within "allowable tolerances" per the specs.  So if I ever needed to make a new image position or make an adjustment I would have to overcompensate in one direction to try to get it right.   It always took many tries until I could get it in an acceptable position.   However that units DI locked up and had to get sent out for repair anyway 6 months later. 

[woofer]

Yeah, again i cant say enough about the support from JVC concerning my issues.

They did not hesitate with , or query my concerns in any manner.... they then organised a replacement unit to be shipped out from Japan...it arrived in Aus 2 days ago, it is in transit and should arrive to me either tomorrow or Monday ...could not ask for more..

[AVSCraig]

JVC here in the US has outstanding customer service. They always have a knowledgeable person available to help customers with issues. 

[AVSCraig]

Don't forget that we can demo the RS4500 in person at our Rochester NY store, or in the Northern California area -

[DavidHir]

Craig, you're going to be famous now.   

[Dylan Seeger]

I still need to get out to Rochester. I would love to see one of these in person! It's a bit of drive that's the only reason why I haven't made the trip.