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Help me design my home theater - planning stage

27K views 147 replies 19 participants last post by  DIYHomeTheater 
#1 ·
I am a novice at designing theaters, and am self-taught by gleaning information from the Web for doing this. I have developed a design for my basement home theater and welcome any insights based on design reviews by the excellent comments people have made on this forum. My design principles are as follows:
  • Get the largest acoustically transparent screen as possible for the space available. Recognize that projectors may be too expensive today for such a large screen, but prices will eventually fall. I can change projectors, but not screens and false walls easily.
  • Trade a perfect' expensive- for an 80% good' reasonably-priced solution
  • Use the lessons learned from others


Accordingly, my plan (see attached floor plan) in no particular order (although I paid the most importance to the screen and seating) is as follows:

Room
  • Finished dimensions 28'5 long, 17' 11 wide, 8' 7-3/4 high
  • Carpet on floor
  • No lights in the ceiling, but sconces on the walls
  • A 6 high stage in front of the screen

Room Acoustics
  • According to Auralex Acoustics Inc., a 29' 10 room length delivers the most ideal frequency response between the possible dimensions listed' based on a similar plan
  • Room sound isolation to be achieved through RC channels , two 5/8 drywall panels with Green Glue in between
  • Mineral fiber between floor joists in ceiling? Not sure about this. (update 1/26/11: Installed R-19 in ceiling and R-13 in walls on advice of the Soundproofing Company. Was not expensive: Material cost ~$300. Seems like an entirely worthwhile thing to do based on its property to absorb low frequency bass)
  • Auralex-recommended schedule consisting of S3PP ProPanels, S3CT corner traps and SpaceCouplers suspended from the ceiling as follows (from Auralex):

  • S3PP ProPanels should be spaced evenly throughout the available open wall space to reduce room ring and slap back. Panels should start between 2 and 3 feet up from the floor

  • Additional low frequency absorption can be gained by spacing the S3PP ProPanels off the walls 203 inches, creating an airgap behind the panels. This can be easily done using small wood blocks or something similar

  • S3CT Corner Traps should be mounted in the available upper corners to help smooth low frequency inconsistencies

  • SpaceCouplers could be suspended from the ceiling over the listening areas to break up first reflections and help widen the sweet spots
  • Consider lower-cost, generic DIY alternatives for the above, if available

Screen
  • 2.40 aspect ratio, flat, 187 diagonal, 172.8 wide, 72 high (update 1/21/11: Revising screen dimensions based on discussions with Chris Seymour of Seymour AV and others on this forum. Brand Screen Excellence acoustically transparent Craftsman screen, 1.0 gain, EN4K material with GripFix. I chose this over others for its DIY-friendliness and good performance/cost update 1/21/11 - this fabric is no longer available for DIY market. Now considering the Center Stage XD fabric
  • Develop a 4-way masking system using the methods described on this forum

Audio: Use my existing B&W speaker system - 803 Matrix and HTM center channel, and 800 ASW subwoofer. Will need to purchase new surrounds and perhaps additional subs.

Seating
  • Two rows of 4-each 18' and 25' away from screen. Distances established by using Carlton Bale's calculator for THX recommended distancesupdate 1/21/11: moved rows forward with smaller screen and gave more space at the rear
  • Modify riser to function as a bass trap

Projector
  • Will need 1100+ calibrated lumen projector eventually. May initially get the BenQ W6000 which is reasonably priced and has high output. May not use entire screen initially
  • Anamorphic lens - most likely the Isco IIIs
  • Maximize throw distance to reduce distortion, but aim for about 20 foot-lamberts on screen

Equipment rack in separate room

HVAC: This is one area that I am not sure how to handle sound isolation. HVAC registers will be above and behind the seats and returns will be on the left wall between the doors. I have a variable speed fan which is usually very quiet. Also, our basement tends to be a comfortable temperature and I don't forsee the heating/cooling being turned on. But, just to be safe, I did get the HVAC engineer to consider options for acoustics. He recommended a separate thermostat in the theater and a separate trunk line with automatic gates' for the theater. I am not sure how to prevent sound from the rest of the house/air handler from reaching the theater, and am not sure if this arrangement will provide sound isolation. He suggested a liner in the ducts that absorbs sound. The contractor's recommendation is, "Install two 12x6 high wall registers behind seating. Install a 16x16 low wall return air grille with a 10x8 return duct. The new supply air trunkline and return air riser duct are to be lined to reduce noise." update 1/21/11: Dennis Erskine gave great suggestions. Located supply and return registers up high. Supply at the front and return at the back near PJ. Pointed downwards, bar-type, 4"x48". Insulated flexible 8" ducts. Air flow = 340 CFM for 10 people+equipment. Capable of being zoned separately in the future. Air speed at registers kept below NC20 noise criteria 250 fps.


Any suggestions will be welcome. Thanks, all!

Edited 1-21-11

I walled off the curved space in the theater on the advice of Auralex. The curved space is especially difficult to treat acoustically. By walling it off, I can use it for my equipment rack

 
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1
#2 ·
My initial reaction is move the seating closer to the screen and go with a somewhat smaller screen. Then you would have more choices of projectors.


Put a sit at bar at the back for overflow seating.


Unless you are planning on using the space in front of the first row as a dance floor that is a whole lot of wasted real estate.
 
#3 ·
Get rid of the Resilient channel, hurts you for LFE sound isolation.


Take a look at the 4th link in my sig for links to the soundproofing company. Their library is essential reading. From there they will tell you insulation (absorbtion) is an important prong, but the type of insulation in your wall or ceiling cavity is less critical. Amongst many other things.


Your dimensions are a nice size, but I wouldn't invest one iota in Auralex saying that 29' is best. There is no best. There are no "golden ratios", plan your space for your intended use (start with seating capacity) and then go from there.


A well sealed room requires a suitable HVAC system. Plan it ahead. Dennis recommends that the ducts be sized as if it were a kitchen.
 
#4 ·
I second moving the seats forward. You will have imaging problems with the back row being right up against the back wall.
 
#6 ·

Quote:
Originally Posted by dc_pilgrim /forum/post/18398618


Get rid of the Resilient channel, hurts you for LFE sound isolation.

It's not clear if the OP meant RC channel as Resilient Clips and channel or RC1/RC2 the former is good, the later not.
 
#7 ·

Quote:
Originally Posted by BIGmouthinDC /forum/post/18398888


It's not clear if the OP meant RC channel as Resilient Clips and channel or RC1/RC2 the former is good, the later not.

True. But given that one is bad, but often recommended by people who know nothing about isolating LFE, I assume the worst and put the warning out there.


Then again, I just clicked the link. No clips on the link.
 
#10 ·

Quote:
Originally Posted by dc_pilgrim /forum/post/18398984


True. But given that one is bad, but often recommended by people who know nothing about isolating LFE, I assume the worst and put the warning out there.


Then again, I just clicked the link. No clips on the link.

I believe that the best way would be to use a combination of clips and channels, correct?

Quote:
Originally Posted by BIGmouthinDC /forum/post/18398335


My initial reaction is move the seating closer to the screen and go with a somewhat smaller screen. Then you would have more choices of projectors.

Moving the seats further forward conflicts with the guidance provided by Carlton Bale:


For this screen, the shortest distance recommended is 10.3'

"Shortest Recommended Viewing Distance based on Field-of-View being too wide: This distance is based on the peripheral vision field-of-view of the human eye. The average field-of-view width for the human eye is 140 degrees. The rule is that if the viewer sits any closer than this distance to the screen and looks at one side of the screen, they will not be able to see the other side of the screen with their peripheral vision. This equates to a 70-degree field-of-view when the person is looking at the center of the screen."


In addition, the THX longest recommended viewing distance is ~22'


Everything that I have read on this forum indicates that one should try to get as big a screen as the space will reasonably allow.


Based on your thoughts, I could move the seating to be between 14' and 21'. For a screen this size, there will be some 'wasted' space in the front.

Quote:
Originally Posted by dc_pilgrim /forum/post/18398618


Get rid of the Resilient channel, hurts you for LFE sound isolation.

I believe that the manufacturer's recommendation is to use the clips (e.g Whisperclips ) in combination with an RC channel , correct? If so, I will incorporate both in the design. What I don't understand is how adding the clips reduces the contact area between drywall/stud vice using just the channel? In both cases, the contact area should be the same. The Phillips Channel comes in many varieties, some that attach to the drywall on only one side, vice both sides. How/why would adding a clip make the difference? I am sure that answer is obvious to all, but I just don't get it.


What is LFE?


"Your dimensions are a nice size, but I wouldn't invest one iota in Auralex saying that 29' is best. There is no best. There are no "golden ratios", plan your space for your intended use (start with seating capacity) and then go from there."

I have read about standing waves and room modes and that the worst possible room is a cube. Ethan Winer makes some recommendations about room sizes if you can control them.


"A well sealed room requires a suitable HVAC system. Plan it ahead. Dennis recommends that the ducts be sized as if it were a kitchen."

My contractor recommends, ""Install two 12x6 high wall registers behind seating. Install a 16x16 low wall return air grille with a 10x8 return duct. The new supply air trunkline and return air riser duct are to be lined to reduce noise."

Quote:
Originally Posted by jelloslug /forum/post/18398632


I second moving the seats forward. You will have imaging problems with the back row being right up against the back wall.

Duly noted. Any risk that I might be too close at 14'? How close can I get the front row to be?

Quote:
Originally Posted by rader /forum/post/18398693


Why not go with a higher gain screen, given the size you want?

You could save a lot of $ by going DIY on the acoustic panels (Owens Corning 703 or linacoustic) over Auralex.

I can't find higher gain, acoustically transparent screens. Will certainly consider the other acoustic materials that you suggested


Thank you all. This is very helpful.
 
#11 ·

Quote:
Originally Posted by DIYHomeTheater /forum/post/18400058


I believe that the manufacturer's recommendation is to use the clips (e.g Whisperclips ) in combination with an RC channel , correct?
NO rigid hat channel is used with whisper clips not RC channel. It would become painfully obvious when you tried to fit the channel into the clip.



RC1




Hat channel




assembled view

 
#12 ·

Quote:
Originally Posted by BIGmouthinDC /forum/post/18400423

NO rigid hat channel is used with whisper clips not RC channel. It would become painfully obvious when you tried to fit the channel into the clip.

Thanks. Very helpful. How do I handle sound isolation in the curved wall? I can use only 1/4" drywall there for flexibility. I can't use hat channels. So, I was thinking that I might use 3 or 4 layers of 1/4" drywall there. Will that work?
 
#14 ·
Post a diagram of your plan and it will be very helpful in getting more suggestions, and essential in planning things out for yourself.
 
#15 ·

Quote:
Originally Posted by DIYHomeTheater /forum/post/18400774


Thanks. Very helpful. How do I handle sound isolation in the curved wall? I can use only 1/4" drywall there for flexibility. I can't use hat channels. So, I was thinking that I might use 3 or 4 layers of 1/4" drywall there. Will that work?

Just an idea:

Mount the hat channels vertically one for each stud. Use the 1/4 drywall (3-4 layers) and use Green Glue dampening goo between layers. Put a dense rubber isolation pad (hockey puck) under the bottom of each channel as gravity will pull it down. I would flare the bottom edges of the channel to spread out the weight.
 
#16 ·

Quote:
Originally Posted by 3fingerbrown /forum/post/18401074


Post a diagram of your plan and it will be very helpful in getting more suggestions, and essential in planning things out for yourself.

A picture of the layout is attached to first post in this thread. Also, here .


Quote:
Originally Posted by BigMouthinDC /forum/post/18401123


Mount the hat channels vertically one for each stud...

That's a great suggestion!
 
#17 ·

Quote:
Originally Posted by BIGmouthinDC /forum/post/18400423

NO rigid hat channel is used with whisper clips not RC channel. It would become painfully obvious when you tried to fit the channel into the clip.

Check the Auralex website - -they don't seem to be using any clips.
 
#18 ·

Quote:
Originally Posted by SierraMikeBravo /forum/post/18400900


That was what I was trying to elude to in my previous post. You are going to have a difficult time acoustically with that curved wall as well as all the bump outs. It may present more challenges than it is worth. Best wishes!

Unfortunately, short of moving my theater to a different location, I have no choice with the bumpouts or the curved wall. It is what it is in my home.
 
#19 ·
You can do some research on the topic of RC channel versus isolation clips and hat channel. The industry pros seem to lean toward the clip and channel approach. Maybe Ted White has an article summarizing the differences.
 
#20 ·

Quote:
Originally Posted by BIGmouthinDC /forum/post/18401338


You can do some research on the topic of RC channel versus isolation clips and hat channel. The industry pros seem to lean toward the clip and channel approach. Maybe Ted White has an article summarizing the differences.

Is sound isolation through channels/clips on below-grade foundation walls against unexcavated areas advised? Or is it pointless?
 
#21 ·

Quote:
Originally Posted by DIYHomeTheater /forum/post/18401334


Unfortunately, short of moving my theater to a different location, I have no choice with the bumpouts or the curved wall. It is what it is in my home.

Maybe you could use the curved area as space for an equipment rack. Then you can frame the wall straight across int he front.
 
#22 ·

Quote:
Originally Posted by In2Photos /forum/post/18401425


Maybe you could use the curved area as space for an equipment rack. Then you can frame the wall straight across int he front.

That's another great idea! I had thought of that, but felt that the curved niche might look good. But, it is dead space and of not much use. Besides, it focuses sound that might need heavy padding to deaden it. Putting all the gear there might be best. Thanks.
 
#23 ·
What do people think of hard floors for a theater? Here is what Ethan Winer writes for a recording studio, " In a studio room, versus a control room, a reflective floor is a great way to get a nice sense of ambience when recording acoustic instruments. Notice I said reflective, not wood, since linoleum and other materials are less expensive than wood yet sound the same. When you record an acoustic guitar or clarinet or whatever, slight reflections off the floor give the illusion of "being right there in the room" on the recording."


Does this logic apply to home theaters, too?
 
#24 ·

Quote:
Originally Posted by DIYHomeTheater /forum/post/18401360


Is sound isolation through channels/clips on below-grade foundation walls against unexcavated areas advised? Or is it pointless?

If you attach the wall framing to the joists above with RSIC 04 clips then it does seem that there is a very small added benefit of using clips and channel on the walls facing exterior foundation walls.


Interior partition walls are another story. Using staggered studs, building a double framed wall with a gap between the frames, and clips and channel are all alternative methods of reducing the transfer of vibrational energy from the wall surface inside the theater to the walls in other living spaces. Personally for theater partition walls I would go for the stagged studs with the top plate non rigidly attached to the joists above. Then a double layer of 5/8 drywall with Green Glue inserted between the layers. Insulate the wall with fluffy fiberglass and use a double layer of drywall with GG on the other side.


Then use the clip and channel for ceiling, unless you build a room within a room and add another set of ceiling joists not touching the sub-floor above. They would rest only on the side walls not touching any other framing.
 
#26 ·
Looks like people are helping to redirect you to some of the techniques used here. I'll add a couple of comments.

Quote:
Originally Posted by DIYHomeTheater /forum/post/18400058


What I don't understand is how adding the clips reduces the contact area between drywall/stud vice using just the channel? In both cases, the contact area should be the same. The Phillips Channel comes in many varieties, some that attach to the drywall on only one side, vice both sides. How/why would adding a clip make the difference? I am sure that answer is obvious to all, but I just don't get it.

I think its two reasons. First, RC is often "short circuited" by a drywall screw anchoring to the stud. The channel used with clips is a little larger that reduces the chance of a short circuit. Plus, since the channel can flex in the clip there is better decoupling. Finally, any of the clips but the cheapest RSIC-V clips (e.g. RSIC-01 or Whisper) have a little gasket I think.

Quote:
What is LFE?

Low Frequency Effect or bass. The hardest part to isolate, and most important.


Quote:
I have read about standing waves and room modes and that the worst possible room is a cube. Ethan Winer makes some recommendations about room sizes if you can control them.

While cubes, domes, circles and spheres are definitely to be avoided, and its also good to avoid dimensions that are integers (e.g. 32x16x8), every room will have modes. My suggestion is to plan to your use and space available. Don't be dogmatic about 29 vs 32 feet.

Quote:
My contractor recommends, ""Install two 12x6 high wall registers behind seating. Install a 16x16 low wall return air grille with a 10x8 return duct. The new supply air trunkline and return air riser duct are to be lined to reduce noise."

I don't know anything about sizing HVAC, but if you build a sealed room, the fact that your basement used to be cooled won't matter when you add a few bodies and heat generating electronics. Ideally you want to be able to control it independantly from the rest of the house, either zones or dedicated systems. For sound isolation, if you tie into the system you can create flanking paths. Lined ducts, non-tin ducts like ductboard, and best of all acoustic flex with multiple 90 degree turns are tricks of the trades. Better yet are independent systems and/or dead vents. Ted has an article on that.


My final suggestion would be to post the entire basement layout, with your goals for your basement. We might be able suggest another way to approach it.


Good luck. I envy the amount of space you have to work with.
 
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