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The official SeymourAV center stage screen thread! - Page 79

post #2341 of 2609
Quote:
Originally Posted by Cam Man View Post

Thank you for posting. I haven't visted an official recommendation like this in a long time...but I'm glad to see that I hadn't missed any changes. My paraphrased descriptions regarding aiming are almost identical in content to that descibed in the paragraph on aiming.

From past readings for which I cannot remember the source, the point of the higher than center positioning of the screen speakers was to place the acoustic center of the speakers where they would be in nominal association with on-screen spoken dialogue. I follow that logic in the home environment.
Does that mean the dialog voice should be higher than the center of the screen?
It seems all the LCR are placed about 2/3, closer to the top of the screen. Does that mean the sound should come from the upper half of the screen? I'm not a pro in cinematography. Does that means majority of action are framed above the center of the screen? confused.gif
post #2342 of 2609
I thought u were supposed to mount the tweeters at ear level while sitting?
post #2343 of 2609
Quote:
Originally Posted by bighvy76 View Post

I thought u were supposed to mount the tweeters at ear level while sitting?

Ear level is perfect when you just have one row but centre of screen common if there are multiple rows. My existing room ear level is in the centre of the screen but I suspect that at the screen will be mounted higher in the new HT room.

-- Bill --
post #2344 of 2609
Quote:
Originally Posted by bighvy76 View Post

I thought u were supposed to mount the tweeters at ear level while sitting?
That's for the typical audiophile setup.
For Dolby commercial theater setup, it's different. The sound is on the upper half of the screen.

(screenshot from the Dolby Atmos whitepaper)

How many of us have LCR placed at the upper half of the screen?
Is there a specific advantage of doing so? Sounds "bigger" tongue.gif?
post #2345 of 2609
Quote:
Originally Posted by rx-8 View Post

Ear level is perfect when you just have one row but centre of screen common if there are multiple rows. My existing room ear level is in the center of the screen but I suspect that at the screen will be mounted higher in the new HT room.

-- Bill --
I've read many articles saying that the general rule of thumb is eye level should be at 1/3 of the screen (from bottom) That means 33.3% is below the eye level and 66.6% is above the eye level. Why is that so? Why not the opposite (66.6% below the eye level)?

How do you like it with yours exactly at the center of the screen? Isn't that the best compare to the 1/3 rule?
Why did the majority place the screen higher than eye level if there's only 1 row of viewer?
post #2346 of 2609
That's how mine is placed...with my eye level on the bottom 1/3. It gives more of a theater effect. My speaker are at ear lever so my l.r.c. are below center line of screen. I think it sounds amazing I angled left and right towards the center of the room slightly.. I have only one row though. I'm using the center stage xd
post #2347 of 2609
Quote:
Originally Posted by Skylinestar View Post

Does that mean the dialog voice should be higher than the center of the screen?
It seems all the LCR are placed about 2/3, closer to the top of the screen. Does that mean the sound should come from the upper half of the screen? I'm not a pro in cinematography. Does that means majority of action are framed above the center of the screen? confused.gif

I'm only going to relate what is done at the professional/commercial cinema and why. You will have to decide whether the logic is sound and should be applied at home.

You don't have to be a pro cinematographer/camera operator to understand the logic behind the 2/3rds screen height placement of the acoustic center of speakers. It's not based on "action." It's based on people/dialogue localization. Think about a medium closeup. Where is the actor's head? In the top third. Even in a tight closeup where the actor's mouth will be nearer the bottom of the screen, you have to consider that much of the human voice comes not only from the mouth, but resonates through the sinuses and eminates from our faces near the mouth/nose. Therefore the 2/3rds screen height still works. But remember that all the sound also does not come from your tweeter/horn (unless you have a Tannoy model or JTR 212). The acoustic center of your speaker, as perceived from your viewing distance, will be (as described in the Dolby document) somewhat central between the tweeter and mid-range component(s). I would contend then that there is a "circle of perception" on the screen of the voice of each LCR that is maybe 1.5' in diameter, not a pinpoint. That's up for research, but that's my theory FWIW. Speakers with good directivity index will still localize highly precisely.

The image/graphic from Dolby is a little misleading in terms of scale of the size of the screen and each LCR stack. That would be like us using a little Bose satellite for LCRs. biggrin.gif Most of us have speakers that occupy a much larger piece of real estate behind the screen, so placing them such that the acoustic center is just above the center of the screen is pretty easy to achieve. I contend that the benefits are strong. Ear level for me at home would put the LCRs near the bottom of the screen. I would find that much more distracting when the speaking actor's head is some 40" above that (in trigonometry maybe 3-4 degrees higher than where the sound is coming from)...not good...at least for me and any professional cinema. Same goes for mixing stages (which are not giant cinemas).

On the other hand, that scale relationship we have at home between speaker size and screen size makes it quite easy. If the acoustic center of LCRs are at least at 1/2 screen height, then it will be indiscernible from 2/3rd screen height...ie "close enough."

One last comment: Since most of us will have a slight look-up angle from our seating position, the higher speaker location is "along" our viewing sightline. Even if the LCR is near the top of the screen or above it, the distraction will be less than if the LCR is too low or below the screen. And all of this is based on listening in a dark room so that there are no visual distraction cues about speaker locations. Of course that is a moot point if you're using an AT screen.

So, I guess that what I'm saying is that if I'm going to make the investment in a fine AT screen like Chris's, I'm gonna get ALL the benefit. smile.gif
Edited by Cam Man - 12/3/13 at 7:11am
post #2348 of 2609
Quote:
Originally Posted by Skylinestar View Post

Quote:
Originally Posted by rx-8 View Post

Ear level is perfect when you just have one row but centre of screen common if there are multiple rows. My existing room ear level is in the center of the screen but I suspect that at the screen will be mounted higher in the new HT room.

-- Bill --
I've read many articles saying that the general rule of thumb is eye level should be at 1/3 of the screen (from bottom) That means 33.3% is below the eye level and 66.6% is above the eye level. Why is that so? Why not the opposite (66.6% below the eye level)?

How do you like it with yours exactly at the center of the screen? Isn't that the best compare to the 1/3 rule?
Why did the majority place the screen higher than eye level if there's only 1 row of viewer?

I've also have read some articles that state that eye level should be 1/3 from the bottom of the screen but that may be better suited for commercial theatres with multiple seating rows and high ceilings. This is not practical for most HT enthusiasts due to our desire for large scenes and typically lower ceilings.

I have mount my screen mounted so that my eyes and ears are at mid screen due to height of the screen and the 7.5' ceiling. Since I only have one row of seating the compression drivers at ear level are perfect IMHO. I do like having everything at mid screen - no neck strain, great sound, and great picture. YMMV.

-- Bill --
post #2349 of 2609
Quote:
Originally Posted by Cam Man View Post

You don't have to be a pro cinematographer/camera operator to understand the logic behind the 2/3rds screen height placement of the acoustic center of speakers. It's not based on "action." It's based on people/dialogue localization. Think about a medium closeup. Where is the actor's head? In the top third.

Even if the LCR is near the top of the screen or above it, the distraction will be less than if the LCR is too low or below the screen. And all of this is based on listening in a dark room so that there are no visual distraction cues about speaker locations.
For the typical non-AT screen user, placing the LCR above the screen is better than placing them below the screen? rolleyes.gif


Logic?
Quote:
Originally Posted by Cam Man View Post

Since most of us will have a slight look-up angle from our seating position
^ Why did the majority have the slight look-up angle? rolleyes.gif
Edited by Skylinestar - 12/3/13 at 8:03am
post #2350 of 2609
Quote:
Originally Posted by Skylinestar View Post

For the typical non-AT screen user, placing the LCR above the screen is better than placing them below the screen? rolleyes.gif
^ Why did the majority have the slight look-up angle? rolleyes.gif

I little off topic, but yes, IMO. Of course, each home environment may have unique issues and limitations (ceiling height, etc).

Typical single level front row seating height is about 30". The top of a front projection screen will be what, 5'-7'? I'd call that a slight look up angle, depending on your viewing distance, right?
post #2351 of 2609
On a side note the lower u Mount your screen the lower the projector has to hang down off the ceiling
post #2352 of 2609
Quote:
Originally Posted by Cam Man View Post

I little off topic, but yes, IMO. Of course, each home environment may have unique issues and limitations (ceiling height, etc).
Thanks for the feedback.

Typical single level front row seating height is about 30". The top of a front projection screen will be what, 5'-7'? I'd call that a slight look up angle, depending on your viewing distance, right?
Is 30" the seating height or eye level? If it's the seating/butt/ass height, the eye level will be another 2'higher. That brings the eye level about 4.5'. I'll call that slight look down angle if the top of the screen is about 5'-7'.
post #2353 of 2609
If u go to any movie theater u always have a slight look up. Unless u sit in the last few rows
post #2354 of 2609
Quote:
Originally Posted by bighvy76 View Post

If u go to any movie theater u always have a slight look up. Unless u sit in the last few rows

That's my point. And, yes, ear/eyeball height is typically about 30".
post #2355 of 2609
post #2356 of 2609
Quote:
Originally Posted by Cam Man View Post

That's my point. And, yes, ear/eyeball height is typically about 30".

That height actually seems a little low to me. My seated ear height on my couch is in the upper 30s (39" IIRC). Of course this will vary by a few inches, but 30" seems likely only if reclined. Maybe I'm unusually high.
post #2357 of 2609
Quote:
Originally Posted by bkeeler10 View Post

That height actually seems a little low to me. My seated ear height on my couch is in the upper 30s (39" IIRC). Of course this will vary by a few inches, but 30" seems likely only if reclined. Maybe I'm unusually high.

You are so right. I don't know how I pulled that number from some scary place in my memory, but terribly wrong. Half-Zheimers, I suppose. Your number of 39-ish" is right...but doesn't affect the core of the discussion; we're still looking up a bit.
post #2358 of 2609
Quote:
Originally Posted by bighvy76 View Post

If u go to any movie theater u always have a slight look up. Unless u sit in the last few rows
If you only have 1 row at home, you have the luxury if not having to look up. With my 7.5 foot ceilings it would be difficult to have people look up anyway. With one row, the center of the screen and the height of my high frequency compression drivers is right above ear level.
post #2359 of 2609
Quote:
Originally Posted by Jedirun View Post

If you only have 1 row at home, you have the luxury if not having to look up. With my 7.5 foot ceilings it would be difficult to have people look up anyway. With one row, the center of the screen and the height of my high frequency compression drivers is right above ear level.

That's a good point. It reminds me of the theater in the photos that I did a few years back in which it was desirable to have a somewhat stadium feel. We kept the second row a little high, and the screen positioned as low as possible but maintaining clear sightlines. It's kind of like forced perspective, but the illusion worked. The perspective of the camera lens makes the screen look smaller/narrower than it is in relation to the seating. Front row center has about a 40 degree HVA, as I remember. EDIT: It is 42 degrees HVA rather than 40 degrees. The luxury in this room was that it was pretty good size (about 21' x 16')...so we the walls and ceiling were a pretty good distance from the screen, therefore no significant retroreflection from them. Surfaces in close proximity are a great challenge...almost demanding a creative bat cave approach as suggested in the next post.

Edited by Cam Man - 12/3/13 at 7:04pm
post #2360 of 2609
Quote:
Originally Posted by SherazNJ View Post

Finally after putting a lot of hours, I was able to put the screen to the test yesterday. Its 141" wide and 164 high screen including borders. Excluding borders, its 134" wide and 57" high screen. The screen is almost hugging the side walls. When I was testing it, I saw the light being reflected back to the side walls, ceiling walls and the floor as well. It was visible enough. As of now, I don't have any Black Velvet fabric on the borders since I'm still waiting for the Velvet tape to arrive, but even if I were to install it on all the borders of screen, would it stop the reflection completely on the walls? If not then what is it I'd have to do to make sure no light is visible beyond the screen?
Thx.

You need to mask the walls + ceiling near the screen. Take a look at this thread.
http://www.avsforum.com/t/1465053/black-theater-improvment-thread-once-you-go-black-you-never-go-back
post #2361 of 2609
Quote:
Originally Posted by chriscmore View Post

We'll simply continue replacing their holy screens while they keep patting themselves on the back.
Does this mean if we're religious, we should seriously consider Stewart screens since they're holy? J/K tongue.gif
post #2362 of 2609
Quote:
Originally Posted by adude View Post

You need to mask the walls + ceiling near the screen. Take a look at this thread.
http://www.avsforum.com/t/1465053/black-theater-improvment-thread-once-you-go-black-you-never-go-back
Thanks so much for the link. That's exactly what I was looking for.
post #2363 of 2609
Quote:
Originally Posted by SherazNJ View Post

Finally after putting a lot of hours, I was able to put the screen to the test yesterday. Its 141" wide and 164 high screen including borders. Excluding borders, its 134" wide and 57" high screen. The screen is almost hugging the side walls. When I was testing it, I saw the light being reflected back to the side walls, ceiling walls and the floor as well. It was visible enough. As of now, I don't have any Black Velvet fabric on the borders since I'm still waiting for the Velvet tape to arrive, but even if I were to install it on all the borders of screen, would it stop the reflection completely on the walls? If not then what is it I'd have to do to make sure no light is visible beyond the screen?
Thx.

The screens black boarders will not stop all those reflections on the side walls and ceiling. I once had my side walls and ceiling painted black flat and even that reflected the image in my bat cave. It really looks horrid with all those reflections over the walls and ceiling. In the end I covered the walls and ceiling in a black fabric similar to velvet, its wonderful now. It also increased the blacks of the image.
post #2364 of 2609
Quote:
Originally Posted by RapalloAV View Post

The screens black boarders will not stop all those reflections on the side walls and ceiling. I once had my side walls and ceiling painted black flat and even that reflected the image in my bat cave. It really looks horrid with all those reflections over the walls and ceiling. In the end I covered the walls and ceiling in a black fabric similar to velvet, its wonderful now. It also increased the blacks of the image.

Yeah I found the whole tread dedicated to this point. Based on what I gathered so far, at least 5' of area should be covered around the screen. Royalty 3 Black Velvet seems to be favorite material to cover and absorb the light. I bought black cotton without knowing about black velvet. Yesterday I bought 14 yard of black velvet and putting velvet next to black cotton, it was obvious way it was preferred. That velvet is as black as it gets. Now in the middle of putting it around. I"ll post some pics when I'm done. A challenge will be to put it on the ceiling.
post #2365 of 2609
Quote:
Originally Posted by SherazNJ View Post

A challenge will be to put it on the ceiling.

I will be doing the same thing. I plan to use 1/4 inch plywood in small pieces so I can handle it, use gaffers tape to hold the fabric to the back of the plywood and then "try" industrial velcro. I used the same stuff when I had RPG Skylines on my ceiling but a word of warning: STAPLE the velcro to the ceiling in addition to the very strong glue on the velcro. Otherwise, one day, a piece will fall.

I am still interested in other, safer" ideas on how to attach it!!
post #2366 of 2609
Quote:
Originally Posted by audioguy View Post

I will be doing the same thing. I plan to use 1/4 inch plywood in small pieces so I can handle it, use gaffers tape to hold the fabric to the back of the plywood and then "try" industrial velcro. I used the same stuff when I had RPG Skylines on my ceiling but a word of warning: STAPLE the velcro to the ceiling in addition to the very strong glue on the velcro. Otherwise, one day, a piece will fall.

I am still interested in other, safer" ideas on how to attach it!!

Why not bolt it to the joists? If you're going to all the trouble to glue & staple velcro to the panels & ceiling, it seems easier (and no less permanent/damaging to the ceiling) to put a couple of short lag bolts up into the joists.
post #2367 of 2609
Quote:
Originally Posted by audioguy View Post

I will be doing the same thing. I plan to use 1/4 inch plywood in small pieces so I can handle it, use gaffers tape to hold the fabric to the back of the plywood and then "try" industrial velcro. I used the same stuff when I had RPG Skylines on my ceiling but a word of warning: STAPLE the velcro to the ceiling in addition to the very strong glue on the velcro. Otherwise, one day, a piece will fall.

I am still interested in other, safer" ideas on how to attach it!!

That seems like a lot of work. I don't think we need to use plywood to cover whole area. Having one on each side (left/right) side of ceiling should do the trick. Then attach the velvet to the sheet and stretch it out from one side of wall to the other. Also I was thinking to use nail gun to hold sheet against the ceiling.

Googling on this topic, I came across an article that explains it. Here is the narrow version of it

1 - Use the stud finder to locate all ceiling joists and mark the locations.
2 - glue the pre-cut plywood in place using panel adhesive. Apply the adhesive to the plywood in a thin serpentine patterned line. Place plywood on the ceiling pushing up against the edge.
3 - Use the pneumatic nail gun to nail the plywood in place. Place the nails where you marked the ceiling joist.


That should do it.

I am also thinking of building a curve stage (a rather small one). Here is the way to do it
http://www.avsforum.com/t/869753/the-copperfields-cinema/60#post_11247083
Edited by SherazNJ - 12/5/13 at 1:18pm
post #2368 of 2609
The picture is crappy but this is what I did. Velvet on 1/4" plywood with spray adhesive. Squirted some liquid nails on the back of the plywood, held it up with the furring strips, and shot some finish nails into the joists that are marked with the blue tape. Did 78" out from where the screen would be. The ceiling is painted flat black and next to the velvet it looks dark gray. There is absolutely zero reflection on the velvet and my screen is only 2" from the ceiling. It was a pain in the ass to do, partly because I was trying to do large panels, but well worth it.

post #2369 of 2609
I bought plywood yesterday and had it cut into 40 inches long and 12 inches wide panels. Built about 10 panels with black fabric and will put them up tomorrow. I think using these panels, putting velvet will be a peace of cake on walls and ceilings. Using adhesive spray made it very easy to put velvet around these panels.

I am also building a small stage in front of the screen. I am using plywood and some wood to support it. It will be 6-8 inches high. I will leave the back side open since its not visible.
My subs are behind the screen. My only concern is if that stage is going to cause any issue with bass? Screen is AT.
post #2370 of 2609
Kind of off topic but why would u make a curved screen. What are the advantaged plus u have to get an "A" lense
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