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Project "C8" - building Norways smallest(?) home cinema

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#1 · (Edited)
Status so far - Finished!:

 
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#2 · (Edited)
In the beginning

Project "C8" has started!

I may be Norways slowest home theater builder, at least when you include the fact that I have been planning this particular room since 2003. I'll not dwell on the reasons for this taking me so long. But you may say I have had enough time to make plans.

I have named the project "C8". This may mean a lot of things, but for me it stands for "Cinema 8". The number 8 has many meanings, it is a chinese symbol for happiness, the floor area of the room is between 8 and 9 square meters, there are 8 channels in a 7.1 system...
There may be other reasons, but by now you may be saying: "8 square meters!???". And, yes, it will be about that size when finished.

This is the reason I think it will be Norways smallest home cinema. There may be some smaller, but i doubt they are dedicated HT rooms, and I doubt they can seat a whole family.

Here are some early planning sketches:



The first sketch shows something about how I imagine the front speaker setup. It is rather old, andsome changes may be made.

Here is another sketch. The speakers will not be like this, but the seating arrangements are close to what I'll be making:



I am not going to spoil the excitement by telling every detail, but here are some points to keep the expectations to a realistic level:
  • There is no room-in-room solution. That would steal too much floor space.
  • The bass acoustics will not be perfect. This must be solved using electronic room correction.
  • It will not be the most beautiful home theater in the world. The finish will be limited of my limited carpentry skills and the fact that the room will be mostly dark.
  • It will not be an all black bat cave.
  • There will be compromises.
  • There will be DIY-solutions
  • A lot of stuff will be done to save and utilise space.

The project has started with cleaning up the room. Here is the unpromising start:









After cleaning and some deconstruction:







I guess a lot of my spare time will be spent on this project. I don't know when I'll finish, that's part of the excitement. :)
 

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#3 ·
:bigsmile:This will be an exciting thread to follow, im having planns for a simullar sort of project, although my floorspace will be a bit bigger.
Wll you be using a big screen tv?, or a projector and a screen?
Have you been thinking about the accoustics?, becouse of the planns that i have, and the size of the room i descided to buy a 5.1 system instead of a 7.1 system and skip the troubles of to much room reflections and phase problems.
(but mayby my way of thinking is incorrect, correct me if 'm wrong)

Snds i live in Sweden, we can say that we are neighbours so.........

Lycka tll!!:wave:
 
#4 ·
Thanx. :)

This HT will definitely use a projector and screen. The screen will be a based on a professional screen material, but the frame and masking will be custom built by me for this room.

I have thought a lot about acoustics, and decided that I will have a 7.1 system. The reason is that I have visited small HTs with 5.1 loudspeakers, and the surround speakers usually get so close to your head that the position of the speaker is clearly revealed, and the space between them not properly filled with the illusion of seamless surround. This works better with 7.1, IMHO.

The biggest challenges is in the bass, but I have some plans there, too... ;-)
 
#6 ·
There is no problem with two center speakers as long as they perfectly in phase.

The problem with the sound coming from below the picture is a larger problem, IMHO. I have also experienced HTs with two center speakers which does the job as good as a center placed behind a sound transparent screen.
 
#7 ·
Your call. There are most definitely cancellations with 2 center channels. Center channels are usually specifically designed to have limited horizontal but good vertical dispersion. When you use 2 of them, you're essentially limiting their vertical dispersion by allowing them to cancel in the center.

If you ever measure 1 vs 2 top and bottom, you'll see it very clearly.

Bryan
 
#8 ·
Yes, the vertical dispersion will be limited. No, there is no cancellation when they are time aligned perfectly in sweet spot, in pretty much the same way as stereo speakers do not have good horisontal dispersion if they are playing pure mono, which is essentially the same as when two center speakers play the same center channel.
 
#9 ·
Color palette for C8

Hi again. I have played around with colors, and have arrived at a palette for interior colors. I'm not sure if reality will match the plans exactly, but these are the approximate colors of C8:



The use of the colors are (from left to right):
  • projection screen
  • grey on door, side walls and back wall
  • ceiling
  • front wall and furniture
  • floor
I think these colors makes this a "quiet" theme. Please note that nothing is said yet on textures... Time will show.
 

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#10 ·
Back again with a status update. This time I am discovering big holes in my english vocabulary, because I don't know what the english word for "spikerslag" is. I'll let the pictures tell the story so far, but know that making holes in concrete has been a time consuming job:





The last wall is not that simple. Here, there is about 80 cm between the "spikerslag", while the standard is 60cm:



There is still some way to go...
 

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#13 ·
"Spikerslag" refers to the vertical wood boards which enables me to fasten stuff to the wall with either nails or ordinary wood screws. In Norway, the standard for this is a center to center measure of 60cm, also referred to as a CC60-standard.
 
#16 ·
I haven't said anything about problems, have I? That something takes time doesn't mean it is a problem. ;-)

The last wall will not be torn down because it is an "anchoring point" (probably not the correct phrase to describe it) for the stairs leading down into the basement on the other side of the wall. Keeping a standard of CC60 all around the room makes symmetry in both construction and esthetics. Keeping the wall is one of the compromises I have chosen to make.
 
#18 ·
First layer of paint in the ceiling and...

Back with new pictures again. Not many structural changes this time, even if the new doorframe represents a bit of work. I have painted the "spikerslag" and two walls. Actually I am uncertain myself why I painted the entire wall, but I think I wanted to check out the visual impression of a complete dark gray wall against the color of the ceiling. But compared to what I have planned, this is unnecessary use of time and paint. I am going to use this color on the door and on the woodwork around it, in corners and towards the floor. I have bought dark gray fabric for the walls, but that is a bit lighter than this color.





I need one or two more layers of paint in the ceiling. It will be a bit exciting to see how it turns out, my first impression is that the color is a bit too much towards red.

The lamp is temporary moved to the wall while painting the ceiling. What do you think I am preparing in the lower part of this wall? You'll get the answer later. ;-)



And, no, I am not talking about the door frame... ;-)
 

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#19 ·
Sub floor started

Just got started on the floor. Didn't get the time to finish everything at once, but laying this is work that progresses pretty fast. You may notice that the walls and floor aren't perfectly rectangular, but I guess this won't be noticable in the finished room.



This picture is from another angle. It may be clearer what I am preparing for in the wooden wall now. ;-)

 

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#22 ·
The ceiling will not be damped. This is one compromise I had to make to save space in this room. The floor will probably get a carpet on top of the projected laminate to remove most of the echo you get when clapping in such a room. Furniture will also cover a decent percentage of the floor space, so it will not be as bad as it is in this picture.

When it comes to walls, they will be damped. Not extremely heavily padded, but a decent damping of acoustic plates of stone wool based mineral fibres, covered with grey stage molton will be on all concrete walls. The wooden wall will get some more damping material.

When the room has no damping and only hard surfaces, of course it is ringing. :thumb:
 
#23 ·
I'll be following this thread!

The non-standard spacing of the one wall can only be a good thing, as the cavities in that wall will have a different resonant frequency from the others. :)

How wide can you make the picture in such a short room?
 
#24 · (Edited)
Yes, I have thought about that, and even if I am a fan of symmetry, I recognise the acoustic benefits of not having the same acoustic flaws everywhere...

The plan is having a screen width of about 170-180cm (it will probably be a DIY 180cm wide screen with aspect 1.85:1), so 16:9 will be 170cm, while the blu-ray movies that usually are around 2.40:1 get a slightly wider picture at 180cm. This is a pretty close viewing distance, but farther away than 1:1, and I like the feeling when the picture pretty much fills up a lot of my field of vision. Masking will probably be added last, and is planned to be customised to both 16:9 and 2.40/2.35:1.
 
#25 · (Edited)
Making wooden wall more rigid and tight

Here we go, another attempt at norwenglish building descriptions. :innocent:

The old storage room walls haven't exactly been the most rigid or airtight of walls. So here we go with one of the compromises I have pondered most before deciding. I could not build a room-in-room solution and double plaster for the full sound isolation effect, deciding it would steal too much of the room width.

But even so I have tried to stiffen and sealing the wall better. I have glued pieces of plaster board between the old studs. In retrospect the sealing is a bit tragicomic. Wanting to try building foam resulted in what is seen below. The building foam expanded to twice the size at once, which I expected. Then, during the fixation process expanded to twice the size once more over some minutes. It is a LOT of stiff foam, and I'll have to cut away a lot.



After this experience, and because some of the wall have to wait for the electrician, I chose to build some boxes instead. These will be needed later in the project.

 

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#30 ·
Re: Making wooden wall more rigid and tight

The building foam expanded to twice the size at once, which I expected. Then, during the fixation process expanded to twice the size once more over some minutes. It is a LOT of stiff foam...
After you cut this foam out, it may benefit you to caulk the same areas with an acoustic caulk. In future areas, I would not recommend this expanding caulk. It has no density and is basically transparent to sound, except maybe high frequencies which it will reflect.

Build for the low frequencies and the mids and highs will be taken care of in that process.
 
#33 · (Edited)
Electrician has been here

I like to do most things myself, but when it comes to complicated electrical work, I have to use professionals. But even if they are professionals, work is progressing slower than expected. Plastic tubes with power cables have been placed in the wooden wall.



Note that I have started to make my own "spikerslag" (studs?) with a CC60 spacing by installing the same 98mm wide planks as on the concrete walls.

Here is another picture from a slightly different angle:

 

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