Building a dedicated listening/home theater room from scratch - AVS Forum
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post #1 of 15 Old 08-17-2011, 02:14 AM - Thread Starter
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The place is going to be built this year so changes are still possible. That`s why I`m opening this thread - to make the changes doable!

I don`t want a real cinema looks, I want to see the equipment and make it accessible so further changes/testing/adding will be possible. I planned a »secret hole« in the other room for easier access to wires.

The room might also be used for occasional computer working and in worst case scenario converted back to regular room – so permanent blocking the windows is not an option.

Here's a thing about insulation: I don't see much sense adding extra insulation over thick brick walls. The whole house is a massive object with 4500 cubic feet of reinforced conrete and 16 tons of steel.
So, there's probably really no sense using any other insulation except some acoustic treatment for the final layer. I'm not even sure about the drywall – maybe on the ceiling to hide some cables but I'd really rather stick with plain walls. The bricks are 1 foot wide plus half foot of facade on the outer side. Neighbours are also not an issue.

In my current room there are a plain sandwich walls (brick, glass woll, brick) and the sub frequency response, for example, is surprisingly good without equalization!
http://www.audio-kontakt.com/galerij...noeq_final.JPG

I was also planning to install an air condition and probably a separated ventilation system placed outside the room.

Equipment so far: old Sony ES pre/pro stuff + JBL Ti series with two Velodyne 15-inch subs would be making a 5.2 system with 5 monopole speakers. Going to 7.2/4 and/or dipole speakers might be considered in the future. The same goes to the 2nd rows of seats!

I want you to chit, chat, comment. I want you to suggest improvements! I want you to do all the wonderful things that you always wanted to but weren't allowed to!

Just kidding! Any suggestions/thoughts are highly appreciated.


Here are some quick and not detailed sketches:

3D placement:


Dimensions:






Equipment:


Screen and sub position






Backview:


Previous version with subs at the sides:
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post #2 of 15 Old 08-17-2011, 06:55 AM
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Quote:
Originally Posted by gerchy View Post

Here's a thing about insulation: I don't see much sense adding extra insulation over thick brick walls. The whole house is a massive object with 4500 cubic feet of reinforced conrete and 16 tons of steel.
So, there's probably really no sense using any other insulation except some acoustic treatment for the final layer.

FYI...sound travels along concrete at 12,000 ft/s and steel at 15,000 ft/s. So, that makes concrete and steel extremely efficient at sound transfer. At 12,000 ft/s, concrete is more than 6 times more efficient than air!

Quote:
In my current room there are a plain sandwich walls (brick, glass woll, brick) and the sub frequency response, for example, is surprisingly good without equalization!

Do you have any data to back this up? Traditionally, glass, concrete, hardwood floor, etc. are not choice materials or surfaces for making a very good sound production/reproduction environment especially when the entire room is made out of these materials.

Shawn Byrne
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post #3 of 15 Old 08-17-2011, 01:18 PM - Thread Starter
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Hi and thanks for your reply,
Quote:
Originally Posted by SierraMikeBravo View Post

FYI...sound travels along concrete at 12,000 ft/s and steel at 15,000 ft/s. So, that makes concrete and steel extremely efficient at sound transfer. At 12,000 ft/s, concrete is more than 6 times more efficient than air!

Since the whole object would be made of bricks I see no sense putting extra wood inside which would make the room smaller. I suppose it is better to put some acoustic treatment on brick walls if needed?
Have you performed any measurements with both surfaces?

Quote:
Originally Posted by SierraMikeBravo View Post

Do you have any data to back this up? Traditionally, glass, concrete, hardwood floor, etc. are not choice materials or surfaces for making a very good sound production/reproduction environment especially when the entire room is made out of these materials.

Sure, I posted a link. Here (click for bigger version):



The room is not empty of course, there are many things inside: shelves with approx. 1000 CD/DVD/BR/MD cases, a sofa, furniture ... and it`s rather small - 130 square feet.
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post #4 of 15 Old 08-17-2011, 03:55 PM
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I was surprised by how much your room resembles mine.

My room dimensions are 17.5' wide 23.5 long, my front row of seats will be about 9 feet from the screen. My screen is 140" about 8" from the floor and 8" from the ceiling. So my front row viewers will have a real eyefull of screen.

http://www.avsforum.com/avs-vb/showthread.php?t=1354094

Like you I also plan on having the computer in the back. In my case the equipment rack would be in the back also.

I also have 2 rear speakers on the back wall making it 7.1 audio.
I'm hoping by putting the speakers up higher and pointing downward, it will eliminate the speaker right in the ear problem.
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post #5 of 15 Old 08-23-2011, 12:28 AM - Thread Starter
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Hi mechatech,

Nice room, I wish I had your dimensions. :-)

The computer in the back is more like a backup plan but it could come handy if HTPC would be needed.

I'm planning to put some extra wires at the back in case of additional speakers.

Looking at your sketch, I see no problems pointing the speakers downward but you might want to try putting them in the corners or on the stands - slightly elevated above the ears.
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post #6 of 15 Old 08-23-2011, 04:17 PM
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How about putting the equipment rack in the back of the theater and eliminating the walls that jut into the room?

I'd also be tempted in shrink the screen size, pull the main speakers off the side walls, and move the front row of seating row in closer (avoiding that row being in the middle of the room).
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post #7 of 15 Old 08-23-2011, 06:08 PM
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Quote:
Originally Posted by SierraMikeBravo View Post
FYI...sound travels along concrete at 12,000 ft/s and steel at 15,000 ft/s. So, that makes concrete and steel extremely efficient at sound transfer. At 12,000 ft/s, concrete is more than 6 times more efficient than air!
Speed of sound through a medium is not the essential question. If the air cannot efficiently excite the concrete, there's less sound to transmit.

Quote:
Compared to a typical wood frame wall, only about one-quarter to one-eighth as much sound penetrates a concrete wall. Acoustics experts would describe loud speech on the opposite side of a frame wall as “audible, but not intelligible.” On the opposite side of a concrete wall, a listener would “strain to hear” loud speech. Through some concrete walls, loud speech would be “inaudible.”

A 2 x 4 wood stud partition wall with ½ in. gypsum wallboard on each side has an STC (Sound Transmission Class) of about 35. With the addition of furring, insulation, and wallboard, STC values up to 63 are obtained for 6 and 8 in. thick concrete walls.
Source.
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post #8 of 15 Old 08-24-2011, 04:56 AM - Thread Starter
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Quote:
Originally Posted by Tedd View Post

I'd also be tempted in shrink the screen size, pull the main speakers off the side walls, and move the front row of seating row in closer (avoiding that row being in the middle of the room).

Well, I'm not happy shrinking the screen size but since stereo reproduction is important to me this could be worth a thought. Speakers in some sketches are temporarily placed according to this method:
http://www.nordost.com/default/downl...0Placement.pdf

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Originally Posted by Roger Dressler View Post

Speed of sound through a medium is not the essential question. If the air cannot efficiently excite the concrete, there's less sound to transmit.

Thanks Roger, that was my initial thought.
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post #9 of 15 Old 01-07-2014, 01:43 PM - Thread Starter
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Some progress has been made. wink.gif

There is a slight dilemma whether the equipment rack comming from the side wall could affect room's acoustic.
The rack depth into the room is 20 cm. It would be sealed from the other side.

Any ideas?

htroom_ome.jpg

rack_acoustic2.jpg

rack_acoustic3.jpg
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post #10 of 15 Old 01-08-2014, 12:49 PM
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Quote:
Originally Posted by gerchy View Post

There is a slight dilemma whether the equipment rack comming from the side wall could affect room's acoustic.

Yes, the rack is very close to the side-wall reflection point. If you can move it back toward the rear of the room a foot or two, that will help. If you can move it all the way back to behind the right surround speaker, that's even better.

--Ethan

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post #11 of 15 Old 01-09-2014, 01:05 AM
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I never did see this or Roger's response. He is correct in this context. I am curious, have you noticed if your sliding glass door helping with low frequency issues associated with high transmission loss values of a concrete room?

Shawn Byrne
Erskine Group
HAA Design Certified -THX Certified Professional

Design-Video & Audio Calibration Information

The original Pro Theater Layout
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post #12 of 15 Old 01-09-2014, 04:25 AM - Thread Starter
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Quote:
Originally Posted by Ethan Winer View Post

Yes, the rack is very close to the side-wall reflection point. If you can move it back toward the rear of the room a foot or two, that will help. If you can move it all the way back to behind the right surround speaker, that's even better.

Moving would be extremely difficult. I guess the only options are to could remove those two mini walls and move the rack 20 centimeters deeper (picture) or to place the speakers closer to the rear wall.

Quote:
Originally Posted by SierraMikeBravo View Post

I never did see this or Roger's response. He is correct in this context. I am curious, have you noticed if your sliding glass door helping with low frequency issues associated with high transmission loss values of a concrete room?

I did not perform any measurements or listening tests in this room yet. I plan to cover those windows with some heavy curtains. What are you using anything else when constructing theaters?



rack_acoustic4.jpg
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post #13 of 15 Old 01-09-2014, 10:48 AM
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Actually, I was just curious if you taken precursor readings with the concrete walls to see how it performed. The sliding glass door will act as a bass trap, so I'm just curious if it is helping to mitigate the inflexibility of the concrete walls in the low frequency range (well all frequencies actually). My suggestion, if you want to use curtains, which is fine, I would use something similar on the opposing wall to balance out the sound. BTW, I totally remember the ES days! Miss them.

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post #14 of 15 Old 01-11-2014, 11:37 AM - Thread Starter
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Quote:
Originally Posted by SierraMikeBravo View Post

Actually, I was just curious if you taken precursor readings with the concrete walls to see how it performed. The sliding glass door will act as a bass trap, so I'm just curious if it is helping to mitigate the inflexibility of the concrete walls in the low frequency range (well all frequencies actually). My suggestion, if you want to use curtains, which is fine, I would use something similar on the opposing wall to balance out the sound. BTW, I totally remember the ES days! Miss them.

No, no readings so far. As you see on the picture above, the room is still in a construction, there is no floor, no ceiling, no doors ... The only thing finished are the 3 separate power lines: Furutech FP314AG, Lapp Ölflex Classic CY110 and a classic copper wire.
Ah yes, the ES days, too bad I was born 10 years too late. frown.gif

Here, some cables and equipment waiting for a new room. redface.gif



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post #15 of 15 Old 07-16-2014, 02:40 PM - Thread Starter
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A little progress has been made.

Central vacuum system pipes for speaker and signal cables:




Bottom of the rack:




Insulation started:



Insulation finished:




Final insulation layer with heating pipes, floor sockets and finished concrete floor.

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