Hi, first post here so thanks for reading this.
I'm undecided between two options for a home theater room size.
I'm worried about room modes as the entire budget will be towards building a concrete shell made of steel re.b.a.r.s, concrete and filled cinder block.
So once built I'm unable to move a wall.
OK I'm undecided between a 10 meters room length and an 11 meters room length with the other dimensions being 7 meters width and ceiling height of six meters.
This is a diy low budget project so I'm really wondering on the impact of room modes in the 10m versus 11m lengths.
Thanks.
My concrete subwoofers box is built but the concrete home theater shell is pending.
The number that is way off is the height of 6 meters. That totally ruins the optimal ratios and is way off. By my calculations that height is way, way out of order, and will make the room ring like a barrel. The difference between 10 and 11 meters is insignificant. Your length to width ratios are in excellent territory.
When I designed my room I worked out essentially optimal dimensions. The room sounds fantastic, and it height is 2.75 meters going to 10 meters is fine, but six meters high makes the room dimension ratios awful.
Incidentally, my room has two concrete walls, the left, and back. The front is stud, but really strong, braced and filled with damping. The right wall is the equipment wall largely. Now concrete is rigid, which is good, however it is all down hill after that. So you cover the concrete with a think layer of insulation ir other dampening material and cover that with sheet rock.
Front.
The back wall. This contains shelving as well as the rear back speakers, to stop slap echo.
The equipment wall.
Make sure in a room that long you tier it, and place damping heavily under the floor.
Make sure you place adequate conduit. All AV wiring MUST be in conduit. Also note the fan duct to extract air from above the power amp case.
Make sure you have adequate AC powering all over the place. Make sure you have power in the vicinity of all speakers, as I'm sure the future is to active powered speakers. Conduit is important to all speakers, not just for speaker wire. But going forward all speakers are likely to require an ethernet connection.
Make the HT room the hub of the house Ethernet.
You are correct that AV rooms require very careful planning. You not only have to plan for now, but future proofing is also vital. This last point is crucial and seldom thought of.
Also, do what I did and create an equipment chase so you can walk behind it. This is a big point.
You are also right, that if you build in concrete there are no do overs, so you HAVE to get it right the first time.