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Heeman - WI Basement HT Build

I would go with putting the TV on the long wall to enhance the stereo imaging and create a stronger 3D depth effect for stereo music.

As for the room dimensions.. .you definitely do not want your two largest area reflective surfaces (floor/ceiling) to be exactly half of your next two largest surfaces (longer walls). So, if the ceiling has to be 7.5 feet, then don't make the shorter wall 15 feet, unless you can angle it somehow.

Think about the simple math.

MODES for Floor to Ceiling reflections: 37.5Hz, 75Hz, 150Hz
MODES for long walls reflections: 19Hz, 37.5Hz, 150Hz

You are guaranteed to have very serious issues at 37.5Hz and 75Hz and likely at 150Hz. which will be damn near impossible to address.

Instead, make the two long walls something like 13.5ft apart, or make the walls with notches, alcoves, and/or outcroppings which vary the distance between them from 13ft to 17 feet.

OR... just leave one side open and make that the rear of the HT.
 
Open is not an option.

AH...........how did I miss the 7.5 - 15 issue....... :angry-tappingfoot:

In the beginning I was talking about a tapered Room.

I could taper from the screen wall from to the back wall. What would be optimum along that 15' distance?

Thanks for your help, I want this to be as good as possible.
 
With my music room being 12 wide and 24 length. I have found that the single seat about three feet from the back provides very good surround and stereo imaging. This will limit your seating to two or three people. What is the target for seating. My screen is on the long wall 24 feet. It is off center and in the back about 8 ft from rear wall.

The tappered wall would depend on the room ratio you want to target some.
I would consider 10 to 12 ft on front and 14 in rear. This would allow you more seating in two rows. With the low ceiling height you may not be able to do the seating riser and would need to stagger the seating some to get the front row heads out of line from the back. 4 to 6 people seating ??
 
With a 10 ft you should find the angle will be 83.7 deg with the wall being about 18.1. With the 12 the angle changes to 86.8 and the wall will be about 18.
So this angle will affect the 90 degree of the first reflections.
 
here is a rough drawing. Outisde box is roughly 14 ft 1st line in 1 foot in and 2 is 2 foot in
giving 10 and 12 foot in center. Rough idea on the first reflect being a 90 degree off the edge of the screen. puts the 1st reflect back around 10 ft.
 

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So, I will make the room with tapered side walls.

The front, screen wall will be 16' wide and the back wall will be 18' wide.

The distance between the front and back walls will be 14'.

Thanks for the help on this Flint and Jerry.

We will go with a single row of seats approx 10' back (to our ears) from the screen.

Still in the planning stage!

:music-rockout: :music-rockout:
 

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heeman said:
The front, screen wall will be 16' wide and the back wall will be 18' wide.

The distance between the front and back walls will be 14'.
Click to expand...
That's a lot of multiples of 2. Can't you tweak those dimensions a bit?
 
Zing said:
heeman said:
The front, screen wall will be 16' wide and the back wall will be 18' wide.

The distance between the front and back walls will be 14'.
Click to expand...
That's a lot of multiples of 2. Can't you tweak those dimensions a bit?
Click to expand...
Not required, I don't think; if you divide each dimension by 2, it's 7 x 8 x 9. That "2" can go into each dimension is completely arbitrary.
Or, he could just convert to metric. :mrgreen:
 
A few inches less here and a few more inches there A) won't cost him anything and B) could very likely avoid (or at least reduce) potential null/peak problems later.
 
on a square room of 8 x 18 x 14.

1 33.1 Hz C1 0-1-0 ax
2 40.19 Hz E1 1-0-0 ax
3 52.06 Hz G1# 1-1-0 tan
4 66.2 Hz C2 0-2-0 ax
5 70.33 Hz C2# 0-0-1 ax
6 77.44 Hz D2# 1-2-0 tan
7 77.73 Hz D2# 0-1-1 tan
8 80.38 Hz E2 2-0-0 ax
9 81.01 Hz E2 1-0-1 tan
10 86.93 Hz F2 2-1-0 tan
11 87.51 Hz F2 1-1-1 obl
12 96.58 Hz G2 0-2-1 tan
13 99.29 Hz G2 0-3-0 ax
14 104.13 Hz G2# 2-2-0 tan
15 104.61 Hz G2# 1-2-1 obl
16 106.81 Hz G2# 2-0-1 tan
17 107.12 Hz A2 1-3-0 tan
18 111.82 Hz A2 2-1-1 obl
19 120.57 Hz B2 3-0-0 ax
20 121.68 Hz B2 0-3-1 tan
21 125.03 Hz B2 3-1-0 tan
22 125.66 Hz B2 2-2-1 obl
23 127.75 Hz C3 2-3-0 tan
24 128.15 Hz C3 1-3-1 obl
25 132.39 Hz C3 0-4-0 ax
26 137.55 Hz C3# 3-2-0 tan
27 138.36 Hz C3# 1-4-0 tan
28 139.59 Hz C3# 3-0-1 tan
29 140.67 Hz C3# 0-0-2 ax
30 143.46 Hz D3 3-1-1 obl
31 144.51 Hz D3 0-1-2 tan
32 145.83 Hz D3 2-3-1 obl
33 146.29 Hz D3 1-0-2 tan
34 149.91 Hz D3 0-4-1 tan
35 149.99 Hz D3 1-1-2 obl
36 154.49 Hz D3# 3-2-1 obl
37 154.88 Hz D3# 2-4-0 tan
38 155.21 Hz D3# 1-4-1 obl
39 155.46 Hz D3# 0-2-2 tan
40 156.19 Hz D3# 3-3-0 tan
41 160.57 Hz E3 1-2-2 obl


125 then 146 and then further up it gets very rough yes. but the angled walls will help along with the addition of Absorbers along the length wall. The addition of the added width will move the first reflections along with the angles on the wall to a point behind the seating. Add in some diffusion on the rear wall to help create the reverb and the 7.1 will be great.

Also it looks like the problem areas are above the sub range and into the mains area. 104 is the start with 2 findings but 125 and up is the problem areas.

Another thing for Heeman, Will you wire for the ceiling channels on Atmos ?
 
The two non-parallel walls will not have a reflection node - or at least it will be vastly reduced to be inconsequential - so I would ignore the 16 to 18 ft taper on those walls.
 
malsackj said:
on a square room of 8 x 18 x 14.

1 33.1 Hz C1 0-1-0 ax
2 40.19 Hz E1 1-0-0 ax
3 52.06 Hz G1# 1-1-0 tan
4 66.2 Hz C2 0-2-0 ax
5 70.33 Hz C2# 0-0-1 ax
6 77.44 Hz D2# 1-2-0 tan
7 77.73 Hz D2# 0-1-1 tan
8 80.38 Hz E2 2-0-0 ax
9 81.01 Hz E2 1-0-1 tan
10 86.93 Hz F2 2-1-0 tan
11 87.51 Hz F2 1-1-1 obl
12 96.58 Hz G2 0-2-1 tan
13 99.29 Hz G2 0-3-0 ax
14 104.13 Hz G2# 2-2-0 tan
15 104.61 Hz G2# 1-2-1 obl
16 106.81 Hz G2# 2-0-1 tan
17 107.12 Hz A2 1-3-0 tan
18 111.82 Hz A2 2-1-1 obl
19 120.57 Hz B2 3-0-0 ax
20 121.68 Hz B2 0-3-1 tan
21 125.03 Hz B2 3-1-0 tan
22 125.66 Hz B2 2-2-1 obl
23 127.75 Hz C3 2-3-0 tan
24 128.15 Hz C3 1-3-1 obl
25 132.39 Hz C3 0-4-0 ax
26 137.55 Hz C3# 3-2-0 tan
27 138.36 Hz C3# 1-4-0 tan
28 139.59 Hz C3# 3-0-1 tan
29 140.67 Hz C3# 0-0-2 ax
30 143.46 Hz D3 3-1-1 obl
31 144.51 Hz D3 0-1-2 tan
32 145.83 Hz D3 2-3-1 obl
33 146.29 Hz D3 1-0-2 tan
34 149.91 Hz D3 0-4-1 tan
35 149.99 Hz D3 1-1-2 obl
36 154.49 Hz D3# 3-2-1 obl
37 154.88 Hz D3# 2-4-0 tan
38 155.21 Hz D3# 1-4-1 obl
39 155.46 Hz D3# 0-2-2 tan
40 156.19 Hz D3# 3-3-0 tan
41 160.57 Hz E3 1-2-2 obl


125 then 146 and then further up it gets very rough yes. but the angled walls will help along with the addition of Absorbers along the length wall. The addition of the added width will move the first reflections along with the angles on the wall to a point behind the seating. Add in some diffusion on the rear wall to help create the reverb and the 7.1 will be great.

Also it looks like the problem areas are above the sub range and into the mains area. 104 is the start with 2 findings but 125 and up is the problem areas.

Another thing for Heeman, Will you wire for the ceiling channels on Atmos ?
Click to expand...



No, but the ceiling will be a drop ceiling so there would be access at a later date.
 
Well, a drop ceiling changes things considerably as the tiles allow bass to pass through. That means lower frequency nodes below 150Hz, or so, will be based more on the reflective surface above the drop ceiling tiles than the bottom of those tiles.

Also, with a drop ceiling you could lay fiberglass insulation on top of the tiles and make that air gap above the tiles into a bass trap. I would use the compressed fiberglass tiles (703 or 705 equivalent) and put cheaper fiberglass batting on top of them.
 
^ My plan was to use Roxul Safe n Sound between the joists tight up against the sub-floor.and have an air gap between the ceiling tiles and the Roxul.

Still planning, this is all good stuff!
 
Flint said:
Well, a drop ceiling changes things considerably as the tiles allow bass to pass through. That means lower frequency nodes below 150Hz, or so, will be based more on the reflective surface above the drop ceiling tiles than the bottom of those tiles.

Also, with a drop ceiling you could lay fiberglass insulation on top of the tiles and make that air gap above the tiles into a bass trap. I would use the compressed fiberglass tiles (703 or 705 equivalent) and put cheaper fiberglass batting on top of them.
Click to expand...

So does this mean that the ceiling height should not be measured to the ceiling tiles but to the sub-floor?

I hope so!
 
Depending on the frequency, yes.

Deep bass energy will generally go right through the ceiling tiles. As the frequency gets higher in pitch, the energy will start getting reflected by the tile - the rate of change will be dependent on the type of tile you use.

It gets complicated for a simple equation to solve.
 
This thread makes me nostalgic for when i was planning my basement theater. It also makes me sad that we are leaving it behind, and that we haven't had any luck finding a house here in OKC that could support such a room. We've been looking at homes that are up to roughly double the sqft of our current house, yet none of them have a room like we have in PA. We're actually considering buying a cheaper, smaller house with a big enough lot, and then adding a dedicated theater room on later.

Good luck, heeman. I like the plan you've got laid out. I may have missed it; will you need any new equipment, or you kept all your stuff from the last house?
 
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