[q80inusa]

I've been a reader of this forum for a while and have finally decided to begin my own HT. This one is not in the States, but in Kuwait. So this may pose some differences to what you guys are used to with regard to sourcing materials and construction methods.


I'm obviously working with the metric system but I have converted some figures to English to ease communication.

The room was part of an open-plan basement, which has been recently partitioned with Insulated concrete blocks on the right and rear side walls (shown in light gray). The existing walls on the front and left is poured reinforced concrete retaining wall (Dark gray). The room is roughly 29' x 15' and has two existing windows. I have purchased 12 HT leather reclining seats and plan to arrange them in 3 rows, 2 of which sit on 2 riser levels. i am also planning for 7.1 configuration and an HDTV front projecting screen.


Like many others, I got overwhelmed with the amount of information on the acoustical treatment master thread. So I've decided to begin this thread to hopefully get some input with the next phase of acoustic treatments. I would really appreciate any help or pointers especially when it comes to treating that curved front wall and dealing with this long theater configuration.

 

[Ted White]

Very interesting! What is the framing and material overhead? Steel / concrete or all concrete?

 

[W00lly]

Some real life Pictures would definitely help everyone get a feel for your space

 

[LarryChanin]

Hi,


Before diving into the acoustic issues you might want to first devote some time to considering your layout in a bit more detail. For instance, where do you intend to place your equipment rack(s)?


It looks like a tight fit to gain access to the front row from the entrance. I have a theater whose finished inside dimensions after acoustic treatments is 15' feet wide. I found I had to use slightly narrower recliners and offset my seating to ensure I had a wide enough single isle for folks to navigate to the seating. I didn't think that two isles on either side would be sufficiently wide to permit easy and safe access for four seat across in a 15' wide room.


Based on you current drawing spacing between isles, in order for someone to come and leave the room, other folks who are reclined will have to unrecline to permit egress. More space will be required between isles to avoid this inconvenient situation.


Click on the link in my signature to see a layout of my home theater.


Larry

 

[Dennis Erskine]

Those two radius front corners will be a nightmare ... but, they can also provide some great opportunities (on the acoustics side)

 

[q80inusa]

Thanks everyone for your replies.


Ted,

the overhead is mesh-reinforced concrete floor 13' high supported by reinforced concrete beams 9' 6" high from the basemen floor to its base.


Dennis,

"nightmare" my thought exactly. So what do you guys think? ho can I benefit from or treat these corners?


Woolly,

I have to photograph the place or dig for older photos of the place. For now I will add some 3d renders of the HT made in sketchup to get a feel for the space.

 

[q80inusa]

Larry,

you make a very good point about the 2 side isles being two narrow (1' 8" each). I am concerned especially since this plan is based on a room with no acoustic treatment which surely will eat more away from the sides. One isle configuration would make my seats fall off-center, so is that okay?


As for the the row-isle spacing, I will consider your comment once I check the dimensions of the chairs (They haven't left their boxes yet). I definitely can distribute the rows further apart once I check the actual dimensions.


I am planning for the Equipment rack to go on the rear wall. with front access to devices from inside the theater, and back access from the opposite side of the wall outside of the theater.

 

[Ted White]

From a sound isolation standpoint, you have a lot of mass there already. Based on your listening experience in other parts of the house with presumably similar construction, what are your thoughts? Are you imagining this is already satisfactory?


You'll want to watch the windows and doors for leaks. Same with ventilation

 

[LarryChanin]



Quote:
Originally Posted by q80inusa /forum/post/16986363


Larry,

you make a very good point about the 2 side isles being two narrow (1' 8" each). I am concerned especially since this plan is based on a room with no acoustic treatment which surely will eat more away from the sides. One isle configuration would make my seats fall off-center, so is that okay?


As for the the row-isle spacing, I will consider your comment once I check the dimensions of the chairs (They haven't left their boxes yet). I definitely can distribute the rows further apart once I check the actual dimensions.


I am planning for the Equipment rack to go on the rear wall. with front access to devices from inside the theater, and back access from the opposite side of the wall outside of the theater.

Hi,


Yes, one isle would put the seating slightly off-center, but what is your alternative, to only invite thin people or small children to sit in the first row of your theater?

Seriously, I have such a slightly off-center arrangement and it hasn't presented any problems either aesthetically or in performance. Just make sure that you don't over do it and place your right-most seating flush up against the right wall.


With regard to the placement of the seating rows, one key factor is to select a screen size so that you can establish the first row seating location. From your drawing it looks like the screen is more than 12 feet wide. For such a large screen the first row would have to be placed about 18.5 feet back to establish a 36 degree horizontal field of view. Any closer than that and the field of view starts to become too large and folks with excellent visual acuity might also start to see image structure, i.e. pixels.


With your equipment rack against the back wall (like in my situation) you obviously have less space available to permit reclining the third row of seating while maintaining an adequate sized isle in front of the equipment to permit access. A rack is going to be about 21" deep and figure about the same distance for access in front.


So now the back of the last row (reclined) is 3.5 feet from the rear wall and the back of the first row is about 18.5 feet from the front wall (assuming the screen is mounted directly on the front wall). That leaves only 7 feet to squeeze the last two rows of seating. A typical home theater recliner is going to take at least 5.75 feet to fully recline. However, the minimum space in front of an unreclined seat should be no less than 42", and figure a typical seat unreclined is about 34" deep, so that comes out to allowing at least 6.33 feet per row of straight seating.


So you see it's going to be impossible to maintain proper seating locations and row spacing with such a large screen. Even with a much smaller screen properly fitting in three rows of seating will still be difficult, if you correctly wish to avoid placing your rear row flush up against the rear wall, or intend to place an equipment rack on the rear wall.


Larry

 

[CJO]

I think that off-center would actually be a benefit in your case. Right now, the center position is between two seat. Move them all over and you might actually be able to sit in the center.


CJ

 

[LarryChanin]

Hi,


One other layout issue that becomes more obvious in reviewing your last 3D rendering is the location of the left side surround speaker. Even if the entrance isle were to be increased by slightly off-setting the seating, it would appear that the speaker is placed at a height and location where folks trying to get in and out of the first and second rows will likely bump their heads on it.


Larry

 

[ScruffyHT]

You will be fine with 3 rows of seating ... allow for 5' at rear ( better for acoustics and for access to your rack ) ... 6.5' per row of seats leaves 11' for the front row


in the 2.35 scope forums they are starting to use 2 X vertical height as the calculation for seating distance to the front row because using width as the factor does not work with scope screens ... seating distance is subjective anyway as some people like sitting closer and others like sitting further back ... with 3 rows you should be able to satisfy all


so with 11' to front row that would give the screen a 66" vertical height = 9.75' wide 16:9 screen or 13' wide 2.35 scope screen


if you go scope screen then try and go no wider than 12' so that you can leave room for L & R speakers


You could also go with a acoustic transparent screen and locate LCR speakers behind the screen ... in that case you would probably have to push everything back 2 feet minimum so back row would be 3' from rear wall

 

[LarryChanin]



Quote:
Originally Posted by ScruffyHT /forum/post/16987146


You will be fine with 3 rows of seating ... allow for 5' at rear ( better for acoustics and for access to your rack ) ... 6.5' per row of seats leaves 11' for the front row


in the 2.35 scope forums they are starting to use 2 X vertical height as the calculation for seating distance to the front row because using width as the factor does not work with scope screens ... seating distance is subjective anyway as some people like sitting closer and others like sitting further back ... with 3 rows you should be able to satisfy all

so with 11' to front row that would give the screen a 66" vertical height = 9.75' wide 16:9 screen or 13' wide 2.35 scope screen


if you go scope screen then try and go no wider than 12' so that you can leave room for L & R speakers


You could also go with a acoustic transparent screen and locate LCR speakers behind the screen ... in that case you would probably have to push everything back 2 feet minimum so back row would be 3' from rear wall

Hi,


I agree that we are dealing with subjective preferences, particularly when dealing with horizontal field of view, but you don't think a horizontal field of view of 61 degrees is excessive? Even if folks don't mind, don't you think that sitting 11 feet away from a 13' screen is likely to present a problem with such things as screen door effect?


Larry

 

[ScruffyHT]

Now we are talking type of projector, flat or curved screens, type of anamorphic lens etc

 

[LarryChanin]



Quote:
Originally Posted by ScruffyHT /forum/post/16987329


Now we are talking type of projector, flat or curved screens, type of anamorphic lens etc

Hi,


Regardless of the technology you don't think a horizontal field of view of 61 degrees will be excessive for the vast majority of viewers?

Larry

 

[ScruffyHT]

The majority of eye strain is not from the horizontal field of view but the vertical height of the screen ... as such 2 X vertical height is being used to determine the closest seating distance to the screen ... in this case he has 12 seats to choose from so for those that are more comfortable with the total immersive effect the front row would be the place to be ... for others there are still 2 more rows to choose from to find the viewing distance that is comfortable for them ... no downside here in a theatre this big

 

[LarryChanin]



Quote:
Originally Posted by ScruffyHT /forum/post/16987420


The majority of eye strain is not from the horizontal field of view but the vertical height of the screen ... as such 2 X vertical height is being used to determine the closest seating distance to the screen ... in this case he has 12 seats to choose from so for those that are more comfortable with the total immersive effect the front row would be the place to be ... for others there are still 2 more rows to choose from to find the viewing distance that is comfortable for them ... no downside here in a theatre this big

Hi Steve,


I'm not discussing eye strain, nor the vertical field of view. I am discussing the discomfort caused by the necessity of having to move one's head in an attempt to follow the on-screen action with such an excessive horizontal field of view.


There was a reason why you recommended that the seating shouldn't be up against the rear wall. Right? In such a large theater surely if folks didn't like the sound in the last row there's lots of other available seating. No?


This doesn't have to be a mutually exclusive issue with some good seats and some bad seats. By selecting a more modest sized screen all seats can be good seats.


Dennis, any guidance you can offer on this issue?


Larry


EDIT:

In my original remarks I didn't mean to imply that three rows can't be accommodated. I think that a screen in the range of 120" diagonally with the first row placed at about 12 feet would probably work.

 

[ScruffyHT]

Larry ... You mention being as far back as 18' for the first row of seats on a 12' wide screen but never clarify as to whether you are referring to a 16:9 screen or a scope screen of that size ... lets at least discuss apples to apples

The reason vertical height is used to determine the first row of seats also correlates with the width of the screen as well ( they go together

) as it mostly pertains to scope screens which are even wider than 16:9 screens ... If that is the reference for scope screens it should be even better for 16:9 content ... you may want to consider what the picture would look like from the last row as well



As I said before the seating distance is subjective and having 3 rows to choose from gives him options ... at least he knows how big he can go before settling for a smaller screen ... check out how many people here are planning screen size upgrades on recently completed theatres

 

[LarryChanin]



Quote:
Originally Posted by ScruffyHT /forum/post/16988162


Larry ... You mention being as far back as 18' for the first row of seats on a 12' wide screen but never clarify as to whether you are referring to a 16:9 screen or a scope screen of that size ... lets at least discuss apples to apples

Hi Steve,


The horizontal field of view has nothing to do with the aspect ratio. The calculation is strictly based on the width of the image at a particular distance. Viewed from the same distance a 16:9 screen 12' wide would present the same horizontal field of view as a scope screen 12' wide.

Quote:
Originally Posted by ScruffyHT /forum/post/16988162


The reason vertical height is used to determine the first row of seats also correlates with the width of the screen as well ( they go together

) as it mostly pertains to scope screens which are even wider than 16:9 screens ... If that is the reference for scope screens it should be even better for 16:9 content ... you may want to consider what the picture would look like from the last row as well

Beyond comfortable field of view considerations, there are viewing distance calculations that consider human visual acuity and set the viewing distance to the eye's critical viewing distance, that is, the distance where image structure (i.e. pixels, scan lines, etc.) begins to be resolved. These calculations are based on the resolution of the projector and can be expressed in actual distances, in screen widths, or screen lengths if the aspect ratio is known.


Yes, it makes sense to consider the field of view from the most distant seating. Some commercial standards recommend keeping the horizontal field of view greater than 27 degrees.


There are also separate standards to guide the vertical height of a screen. Beyond vertical field of view considerations, there are other comfort considerations that have to do with the angle at which we have to hold our heads to view the top of the screen. If I recall correctly if your seating distance requires you to look up more that 35 degrees above the horizon to see the top of the screen, then physical discomfort begins to be a factor. (Some recliners support your head and make this less of an issue.)


Larry

 

[mscott]

Screen size is definitely subjective. I was highly concerned when I built mine. The consensus here was that bigger was better. I built a 13' 16:9 AT screen. I sit at about 12' -- and I can't stop smiling!


As long as you have a HD signal, you'll love it. Just take SD material out of consideration.