Journey from Room to Home Theater with DIY Acoustics

[aloklala]

I am on a journey to create a dedicated Home Theater room out of my normal room on the 1st floor of my Noida house. I am startig off today by adding pictures of the bare bone room and the wood I bought to start the acoustics. :yahoo:

Details of photos below:
1. 1st photo - Enterance door ro the HT room
2. Back wall where the projector will go
3. Left back top corner to show the beam and space behind it in detail
4. Front wall where the screen would go
5. Enterance room door from inside the HT room and the door to the storage space above it

Will post more photos and details shortly.

I request you to provide suggestions on acoustics and anything else you think appropriate.

 

[cmsajith]

I can see the possibility of an IB sub or a "big cement box sub" either sealed / ported (above the door in the last picture)....just a crazy and a possible idea...

 

[aloklala]

cmsajith,

I did not understand what you mean by an IB sub? The small door above the main enterance door is a storage space which I will need and so can't put any HT equipment in it.

 

[aloklala]

Here are 2 more pictures of the Canadian Pine wood that I will use to create the base of frame for the Acoustics.
Each log is 1.5"x1.75"x14'.
My room is 17'(Long)x12'(wide)x9'6''(high)

The children's bedroom is on the fllor beneath this HT room and there is the open roof on the top. One side is the neigbour's house and bathrooms on the 2other sides. The last side behind the projector is a balcony and another neigbour's house beyond that.

 

[cmsajith]

If I have a similar space I would have converted it as a sub enclosure (If you are into DIY) instead of closing / stuffing it (due to resonance). No cabinet resonance / stiffing, nothing reqd, only you have to seal the space properly. Not joking... Once I had read about one horn build below the HT room with enclosure and horn made using cement structure and the horn mouth opening to HT room. If the storage space is big (more than one quarter of the wavelength of the desired freq), it can also be used as an IB sub setup (google)

Eg: http://www.diyaudio.com/forums/subwoofers/197690-concrete-ib-subwoofer.html

Also close all the unwanted openings in the room with bricks itself instead of ply/wood as it will help in sound proofing.

Edit:
Got it.. http://www.royaldevice.com/custom.htm

 

[aloklala]

I was thinking of closing the window using plywood and glasswool. Do you think closing with brick would be a better option?
I have already bought the AV equipment and so buying another Sub now is not possible.
I have bought the following:
1. Denon 3312 AVR
2. Polk Audio RTi A7 Fronts
3. Polk Audio CSi A6 Center
4. Polk Audio FXi A6 Surrounds
5. Polk Audio DWS Pro 660 Sub
6. Epson 3010 projector
7. Monster Speaker, Sub, HDMI and Optical Digital Audio cables
8. I am planning to use a 9x5 fixed screen (Not yet decided which one)
9. Flooring would be carpet
10. All 4 sides of Room will have Acoustics done (will provide details later)
11. I am still deciding on what to do with the roof. A false ceiling will definately be there as i have already bought the lights and LEDs
12. A 6" Step at the back to house a second row of seating
13. 3-4 Recliners in front row (I am not yet sure where to get the recliners from)
14. An HTPC for showing all the Audio and Video content (Not sure yet on how to build one)
15. A 2-seater Sofa and big boss chair in the back row (I am attaching pictures of the Sofa and the boss chair in this post)

 

[ukjeyaraj]

Is the entrance door adjacent to the front wall (where the screen will come). In that case how are you planning to have your FS and Sub. Door open outside or inside the room

 

[aloklala]

Currently the door opens inside but i will have it change to open outside.
I will also have Acoustics done on the inner side of this door and also on the door opening towards the balcony in the back.

 

[bit_ravinder]

I would like to watch First Day First Show :clapping:

 

[ukjeyaraj]

Change in door will be required. Still it will be a challenger to the keep the front speakers, that too a floor-stander. If the entrance is sufficiently wide, you can go for foldable door so that no one will accidently hit on the FS.

 

[aloklala]

I would like to watch First Day First Show :clapping:

Sure Ravinder! You have been my inspiration!!

 

[aloklala]

Change in door will be required. Still it will be a challenger to the keep the front speakers, that too a floor-stander. If the entrance is sufficiently wide, you can go for foldable door so that no one will accidently hit on the FS.

You have a very good point. I have an idea for this which I will show in a diagram in a day or two. Basically, I will create kind of an enclusure around the whole front. I was thinking of making it only of Speaker cloth but on this side I can make it of plywood which can be removed in case I have to take in or take out any large item from the HT room in the future.

 

[manoj.p]

cmsajith,

I did not understand what you mean by an IB sub? The small door above the main enterance door is a storage space which I will need and so can't put any HT equipment in it.

Sajith has a very valid point. The space above the door and air conditioner needs to be filled in and brought to the same height as the beam in the front. Otherwise, it will resonate very badly. Instead, you can build a subwoofer, may be infinite baffle or Tapped Horn type and mount it there. What a great way to use that space.

Also, cover up the window with bricks as suggested. Then do room treatments. Make sure that your room treatments are symmetrical to left and right side to get consistent left and right soundstage.

 

[aloklala]

I will remove the Air Conditioner and put a Split AC in this room. Any suggestion on where the slit AC should go?

All the windows and the space made by AC will be covered by brick or by plywood with glasswool in between to fill the space. Is this a good approach?

The space of 3 ft behind the beam - I was thinking of doing a false ceiling there. Any other suggestions?
Where exactly are you saying I should build the sub woofer? Are infinite baffle or Tapped Horn type kind of sub woofers?

 

[cmsajith]

Sorry, leave it... go ahead...

I could see a lack of planning in your build. Make a clear cut plan and you should start only once you know what you need to do \ have a clear cut plan. Else you may end up spending a lot on unnecessary things and you will not get what you are after. In acoustics, it may not be always 1+1=2, sometimes you may have to do 1+1+1+1-2 = 2 Hope you understand..

 

[santhosh]

Very apt suggestion by cmsajith on using the attic for an Infinite Baffle as the attic will resonate if empty. Here is a nice explanation on IB:
http://www.hometheatershack.com/for...what-ib-infinite-baffle-subwoofer-system.html

Google for pics on Infinite Baffle Subwoofers, you will get a better idea. Will post more links when I am in front of a computer, browsing over phone now.

Manoj, agree with you 100% on the symmetry bit.

 

[aloklala]

Sorry, leave it... go ahead...

I could see a lack of planning in your build. Make a clear cut plan and you should start only once you know what you need to do \ have a clear cut plan. Else you may end up spending a lot on unnecessary things and you will not get what you are after. In acoustics, it may not be always 1+1=2, sometimes you may have to do 1+1+1+1-2 = 2 Hope you understand..

Sajith,
I am not able to understand you completely. There are some things that I have already planned but have not mentioned in this thread.
I had already planned to bring the whole roof behind the beam to the beam level. Also I already had plans to buy a 1.5 ton Split AC for the HT room and remove the Window AC. Also I had planned to cover all the area of above and below the window with bricks or glasswool + plywood, except the door which is the only access to the storage balcony behind.
Thanks,
Alok

 

[aloklala]

I have researched about the IB Subs and Tapped Horn Subs and at this time I think I am not ready to do those. The area (attic) above the main entrance door houses a lot of syuff which I will not be able to remove for at least an year. The area in the back behind the beam is about 2'6'' x 11'11'' x 10'' (height) and I am planning to have acoustic board fixed in the entire area. This will also house 3 lights pointing downwards.
I have also read that IB subs should be the front of the room and not in the back. Is this correct?

 

[manoj.p]

Alok,

I would suggest, you make a plan with layout. Use a free software like Google Sketch to make a 3D plan, with actual room measurements. Then lay things out like, where you would like to keep your screen, speakers, left and rear surrounds, seats, the subs etc. Then you can primitively layout where the room treatments would be. These are primitive. Everyone attacks the corners first and puts corner bass traps. so, you can start there. Your sub placement will also change in the end, depending on the acoustics of your room. But its not bad to plan the probable positions for it.
After you make a layout, post some pictures here and you will get lots of feedback. Put your rest of the plans in it too. If you are not able to make layout, ask a friend or someone's help to make one. As they say in Carpentry - Measure twice, cut once. If you make it without a plan, you will end up spending lot of time and money.

Think about every small detail and include it in detail. In my opinion, the small things about correcting the room make big differences to the audio.

As for the space behind the beam - It cannot be left hollow as well. You will need to fill it with some insulation, so it won't resonate. Leaving it hollow with some playwood on the bottom to level with beam height will make it worse. If you don't use it as a subwoofer space, then I would suggest build a box, fill it with acoustics wool and cover the bottom part with acoustic transparent cloth. You can have lights there with braces. At least this way it will work as a bass trap. The bass frequencies will find a nesting ground there and it needs tamed.

 

[cmsajith]

The answer is in your question in another post "Your HT room and DIY has been an inspiration for me. Now I am also builing a dedicated HT room. Please can you look my thread and guide me on doing the best acoutics possible."

Sajith,
I am not able to understand you completely. There are some things that I have already planned but have not mentioned in this thread.
I had already planned to bring the whole roof behind the beam to the beam level. Also I already had plans to buy a 1.5 ton Split AC for the HT room and remove the Window AC. Also I had planned to cover all the area of above and below the window with bricks or glasswool + plywood, except the door which is the only access to the storage balcony behind.
Thanks,
Alok