Benq TK800M long HDMI cable questions and expectations (1 Viewer)

[Dave>h]

Hi all,

I recently took the plunge into 4k with teh purchase of a (new to me) Benq TK800M projector. This is an upgrade from my rather old Benq w1070, which has done an amazing job over the years with few headaches. I also have a Yamaha Rx V1083 and an LG UHD, the cheaper one.

I bought a 30ft pro series HDMI cable from amazon to connect the projector to the Yamaha and another 3 ft High speed 4k HDMI from UHD to Yamaha.

Playing Oppenheimer 4k, I noticed a lot of pixelization in the background - walls, cabinets etc - as well as on faces and uniforms. I figure this can't be right.

As a test I connected the HDMI directly from the LG to the projector and turn off all the video type processing I could fine on both machines. This improved the picture considerably but there was still some noticeable pixelization in high contrast shots - black and white scenes and scenes with harsh lighting - when they are interrogating Oppenheimer in color for examples. Since it improved but didn't completely fix it, can I assume that the cable is the problem? maybe it says its 4k but over that length it is losing data?

Logistically, I can't move the UHD player close enough to the projector to connect them directly using a shorter cable, in case you are thinking that is an option for testing. Is there any other tests I can run to test the cable?

I've purchased Spears and Munsell for 4k, should arrive today and a "better" HDMI but is there possibly something I have missed that could be causing the problem?

Any and all suggestions graciously accepted and appreciated.

K

 

[Josh Steinberg]

Are you using an active or passive cable?

Although they sell passive cables at lengths longer than 25 feet, they should not be used. A 30 foot run requires an active cable, which are directional (meaning that there’s one end labeled specifically to go into the display device and the other to go into the source device), and use power from the device’s HDMI port to boost the signal to prevent degradation over the longer run.

 

[JohnRice]

At the minimum, an active cable, but even better might be a fiber optic hdmi cable.

 

[Dave>h]

What is this sorcery of which you speak? Active cables, fiberoptic HDMI??? I have never heard of these things?!?

Every turn on this $k journey brings up something new!! Actually, that is a great typo right there $k instead of 4K, this journey is getting more expensive by the minute.

All I can say is I hope ultimately it is worth the effort because so far I am slightly underwhelmed and so is my wife. "It looks the same" she says and she isn't wrong because so far she has only been watching 1080p stuff and can't understand what all the disruption is for. And there has been a bit of disruption - new projector, new location for projector, new cables, new UHD bluray alternatives, getting UHD sources figured out, new streaming content etc etc.

Honestly not exactly sure what I was thinking because I thought this would be simple and relatively cheap but so far it is anything but simple. LOL At least I am having fun. I put it down to the fact that this is my hobby and I really do enjoy it despite all the headaches.

 

[JohnRice]

If you want to see the full visual benefit from 4K, a projector will not accomplish it, regardless of marketing claims. An OLED or good QLED is the only way to do that currently.

 

[Josh Steinberg]

What is this sorcery of which you speak? Active cables

I tried to explain what it was in the post you’re replying to but in short, it’s a cable that draws power from the HDMI ports on your source device to amplify the signal.

HDMI runs longer than about 25 feet are prone to signal degradation.

Normal HDMI cables are “passive” which means that they send the signal from one device to the next without any additional electric use or amplification, and the signal tends to degrade at longer lengths. With old fashioned analog cables on old fashioned devices, signal degradation usually meant being more susceptible to interference or less clear audio or less sharp video. Since modern systems are digital, you don’t get snow in the picture or weak audio - you get their digital equivalents, pixelation and dropouts.

“Active” cables use a tiny bit of power from your source device (in your case, the AVR) to boost that signal so that it can travel longer distances without breakups and dropouts.

All I can say is I hope ultimately it is worth the effort because so far I am slightly underwhelmed and so is my wife.

There are a few factors at play here but in general I would argue that 4K over HD (2K) is more incremental than revelatory in most cases.

A lot of modern films are completed at 2K resolution, so even if it’s being presented on a 4K disc, it doesn’t necessarily have a full 4K’s worth of resolution. Older films shot on 35mm film may not always have 4K worth of information on the film negative either.

One of the big selling points for the 4K format was the inclusion of HDR - high dynamic range - which in short means that there’s a wider range of tones and colors the format can reproduce. The whitest whites are brighter than SDR (standard dynamic range, which every prior format has used), and the darkest darks are darker than SDR.

But projectors have great difficulty handling the extremes of brightness and darkness that an HDR signal can carry, so the effect of viewing something in HDR on a projector tends to be more muted than viewing that material on a flat panel television.

And so, if you have movies where there isn’t much more resolution present to use in 4K over 2K, and projectors can’t fully see all of the HDR detail.. that’s how you end up looking at something on a new 4K projector and not seeing much more or much of a difference over regular HD.

 

[Dave>h]

There are a few factors at play here but in general I would argue that 4K over HD (2K) is more incremental than revelatory in most cases.

A lot of modern films are completed at 2K resolution, so even if it’s being presented on a 4K disc, it doesn’t necessarily have a full 4K’s worth of resolution. Older films shot on 35mm film may not always have 4K worth of information on the film negative either.

One of the big selling points for the 4K format was the inclusion of HDR - high dynamic range - which in short means that there’s a wider range of tones and colors the format can reproduce. The whitest whites are brighter than SDR (standard dynamic range, which every prior format has used), and the darkest darks are darker than SDR.

But projectors have great difficulty handling the extremes of brightness and darkness that an HDR signal can carry, so the effect of viewing something in HDR on a projector tends to be more muted than viewing that material on a flat panel television.

And so, if you have movies where there isn’t much more resolution present to use in 4K over 2K, and projectors can’t fully see all of the HDR detail.. that’s how you end up looking at something on a new 4K projector and not seeing much more or much of a difference over regular HD.

This is a most excellent explanation and I really appreciate it!

I have a rule. I can only purchase UHD for films that I don't already own in HD. However, the UHD must also be better than the current HD offering or comparably priced (either works and I tend to be bit fast and loose with the rules but...). Probably there is a thread already on this topic but maybe you have some great suggestions for UHD. I read a lot of Robert Harris reviews (hope I got his name right) on here as I trust his opinion, objectiveness and expertise.
Thanks very much for your comments!

Dave

 

[JohnRice]

One thing to keep in mind, a lot of (particularly) early Blu Ray transfers were really bad. There are many cases where a new transfer on UHD will be significantly better, even if the fact it is a UHD disc isn't necessarily a big part of the improvement.