Irregular Home Theater Room Shape - Will I Have Audio Issues?

[ccmichaelson]

I really appreciate all the ideas/comments.  The reason I posed this topic was that I have some flexibility in modifying this room (slightly) during construction <if needed>.  The architect is not a HT guy by any means so the seats depicted and their location are inaccurate - I'm planning to have perhaps 2 rows w/ 4 seats per row and perhaps a back row with 2 seats + I like the idea of a bar/table in back area to eat.  I'll review the AVS forums as suggested.  My biggest concern is the v-shaped back wall but it doesn't sound like that will be a show stopper (I'm okay with a less than perfect setup - unlike Bill Gates I have to work for a living)...  thx

 

[pete_c]

Welcome to the Cocoontech forum; stick around; its a friendly place to be. (well virtually).
 
Great news ccmichaelson!
 
It's really about what you want as stated by drvnbysound. (I like that "people measurebators and/or pixel peepers" statement)
 
Here on the CT forum many users are DIYer automation folks.  
 
Today with the current evolution of technlogies; CT users knowledge base,  many of the folks here have DIY'd similiar endeavors for their current homes new pre construction, during construction and post construction.  Literally pouring foundations, nailing in studs, putting walls in, doing the electrical and low voltage infrastructure work or just subcontracting to having it done to their own "learned" theater specfications.  (similiarly on the AVS forum).
 
Tell us how you progress with your endeavor and show us pictures of the final product once completed.

 

[ccmichaelson]

Thanks Pete (and others)...  I'm also planning to do all of my low voltage wiring for home automation too so I've already been studying CT for ideas/suggestions.  I will have MANY questions along the way and finding CT very helpful.

 

[pete_c]

More related to automation of your new Home Theater...
 
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Join Electronic House Online Editor Grant Clauser and iRule and On Controls CEO Itai Ben-Gal for this informative look at custom control and automation and learn how to put the magic of custom control and automation in your room!
 
Attend this webinar on Thursday, Nov 20, 2014 8:00 PM EST and be eligible to win a giveaway package including:
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[jautor]

I really appreciate all the ideas/comments.  The reason I posed this topic was that I have some flexibility in modifying this room (slightly) during construction <if needed>.  The architect is not a HT guy by any means so the seats depicted and their location are inaccurate - I'm planning to have perhaps 2 rows w/ 4 seats per row and perhaps a back row with 2 seats + I like the idea of a bar/table in back area to eat.  I'll review the AVS forums as suggested.  My biggest concern is the v-shaped back wall but it doesn't sound like that will be a show stopper (I'm okay with a less than perfect setup - unlike Bill Gates I have to work for a living)...  thx

 
+1 on Neurorad's suggestion about leaving the space unfinished until "later".  I did that for a number of reasons - time to design the space, and money to apply to it.  I documented my process, after the fact, here:  http://www.avsforum.com/forum/19-dedicated-theater-design-construction/1385501-jautor-s-rock-creek-theater-post-build-retrospective.html#post21454151
 
I would also highly recommend the "What I would do different next time" thread over at AVS as well - that's an invaluable resource for the DIY theater builder.
 
While the odd shape in the back of the room won't be a killer issue, if you can alter the floorplan as suggested to better utilize that square footage in the bathroom, for instance, you'd probably be doing yourself a favor.  But that area could also be closed off for an equipment closet, too!  As for audio performance, it's certainly not going to "ruin" the room...
 
Jeff

 

[Neurorad]

I'd say the latter depends on how in-depth/detailed you want your home theater to be. Personally, I don't care if my setup is THX certified, if my screen is calibrated on a weekly basis, if the speakers perform perfectly at reference volume, etc. I don't care to be that scientific about it. I simply want a space to enjoy movies with friends/family... and that includes a large screen and surround sound. The blacks of said screen may not be blacker than black (BTB), and the whites may not be whiter than white (WTW); for those who don't know, those are real terms used when you start digging into this stuff. Sure, if I've got a Bill Gates budget, I'm paying for those things even if I can't tell the difference, but that's simply not the case.
 
 
So, regarding your home theater, what's good enough for you? What meets your requirements?

There are some basic tenets of home theater that are often ignored, really simple stuff.  Sure, there are many HT fanatics that are over the top when it comes to AV, but putting a little time in can be productive.
 
At a minimum, you need to revise the number and location of seats, and modify HVAC, especially if your equipment will be in the same room.  Obviously, run all cables you need before drywall goes up, including power and control to the projector (I'd run conduit to the PJ, personally, plus HDMI and category cable x 2).  If you're thinking about powered recliners for some or all seats, take that into account when spacing - and you'll need power to the seats.
 
If you want to go bigger on the screen, you can use an acoustically transparent screen, and put the speakers behind it, using a false, fabric covered wall.  But, that's crossing the line into crazy, according to some.  It's pretty easy to do, especially if someone else does it.  I really don't know how big is too big, for a screen, but an experienced HT designer/installer would know.
 
Just some ideas to chew on.

 

[drvnbysound]

Sure, my point was that I wouldn't be the person who leaves the space unfinished for 2 years while I research what screws to use to mount my projector because they are acoustically transparent and cause no "measurable" sound reflections. Instead, I'd go with an 90% solution today and enjoy my setup for the next 2 years and beyond.
 
My example may be a bit extreme, but I've seen other stuff posted on AVS that wasn't too far from that... which gets far too scientific for me. I put the word measurable in quotes (above), because there are those who will find the difference via a microphone measurement, but can't actually hear the difference. If I can't see or hear the difference, I don't really care about it because it doesn't change my enjoyment.

 

[jautor]

Sure, my point was that I wouldn't be the person who leaves the space unfinished for 2 years while I research what screws to use to mount my projector because they are acoustically transparent and cause no "measurable" sound reflections. Instead, I'd go with an 90% solution today and enjoy my setup for the next 2 years and beyond.

 
The problem with finishing the room without adequate research is that so many of the fundamental mistakes made in home theaters are easily correctable prior to the sheetrock going up.  Wiring, HVAC, speaker placements, sound isolation (soundproofing), riser sizes, seating distance, etc.  
 
For example, while my own room was left unfinished during construction, I did have the builder construct the risers into the framing.  Which was a mistake - they should have been ~1' deeper to provide more room for the recliners.  Couldn't fix that after the fact without a huge expense - whereas during construction that would have been a simple measurement change.
 
And none of that is anywhere close to being the pseudoscience fringe... 

 

[LarrylLix]

If it is a basement I would never, ever, finish the ceiling in drywall. Use a nice looking suspended ceiling. Finished drywall basements are a problem for that one cable you forgot to install, plumbing changes, access to the walls upstairs for another HVAC or HRC 'stat, etc... etc.. I know too many people that drywalled their ceiling only to regret it later living on WiFi with jerky videos and bad sound on their VoIP phones.

Suspended ceilings will give a much better sound insulation and absorption and ability to further insulate some upstairs device or the general ceiling should the sound travel be too much.

 

[jautor]

If it is a basement I would never, ever, finish the ceiling in drywall. Use a nice looking suspended ceiling. Finished drywall basements are a problem for that one cable you forgot to install, plumbing changes, access to the walls upstairs for another HVAC or HRC 'stat, etc... etc.. I know too many people that drywalled their ceiling only to regret it later living on WiFi with jerky videos and bad sound on their VoIP phones.

Suspended ceilings will give a much better sound insulation and absorption and ability to further insulate some upstairs device or the general ceiling should the sound travel be too much.

 
The experts would disagree with you regarding the absorption / isolation quality of drop ceilings vs. drywall.  They simply don't have the mass needed to contain low-frequency energy that is typically the problem for home theaters.  
 
http://www.soundproofingcompany.com/soundproofing-articles/i-am-planning-a-dropped-ceiling-in-my-basement-how-should-i-treat-my-walls/
 
As for access to above - I'd agree that having that is a good thing, and for the rest of the basement I'd probably do the same thing.  But for a dedicated theater the drywall wins.  Also, placing additional drywall mass between the joists on the subfloor above can help with footsteps and other noise coming from whatever is above (worst is a kitchen or other high-traffic rooms with hardwood floors).
 
But to compensate for the lack of future access above the theater - run lots of wires (cat5e/cat6 and at least one coax) to those rooms, and flex conduit if there's a primary AV location that would be affected...
 
Jeff

 

[drvnbysound]

Yesterday was my wife's birthday and she wanted to go see the latest Hunger Games movie... said theater had a drop ceiling

 

[dgage]

You've had quite a bit of good advice, especially the links to AVS. I also would recommend cutting off the back of the room as was drawn up for you. If you really want to move forward quickly, hire an expert such as Dennis Erskine or Nyal Mellor.

I've recently gotten into measuring my speakers as they weren't meeting the specs I expected. One thing that was an eye opener for me was HOW MUCH the room interacts with the speaker response. Even with the mic 3 feet in front of my speaker, room modes can really affect the response. My own room has a 100Hz drop on one side and some issues in the 300-400Hz range on the other. I've measured several of my friends rooms and have seen similar room modes, even in treated rooms. I also agree you don't want a square and you want to minimize parallel lines...you definitely won't find a concert hall with parallel lines.

If it were me, I'd look to a baffle wall with the speakers and some subs up front. I'd also sprinkle some subs throughout the room (mid-walls) to even out the bass response throughout the seating. I'd make sure to have bass traps in the corners of the room, including the wall to ceiling intersection. I'd also have a mix of diffusion and absorption on the walls and front ceiling. A theater designer can help you with the treatment designs, especially addressing the first point reflections.

Regarding equipment, you might want to take a look at some of the higher output speaker designs such as JTR Speakers (212HT,215RM) or Seaton (Cat12s). My JTR 212s offer such dynamics that it is disappointing going to a theater now, at least on the audio side. Those two companies also offer some really nice home theater subwoofers in the JTR S2 and Seaton Submerssive. I am also starting a company (Deep Sea Sound) offering home theater subwoofers around a beefy 18" driver and a 24" subwoofer that is a beast yet clean,deep, and quick. I'm finalizing details and should start taking orders within the next few weeks, currently building subs for my first customers/friends.

Where are you located? Depending on where you are, I might be able to put you in touch with some people to hear their theaters.

 

[Del91574]

Drop tile ceilings are far better at attenuating the transference of sound from room to building structure to another room/area. The argument that the mass isn't there is laughable...sorry. It doesn't need to be there and in actuality, it's best that it's really not (unless we're talking about putting sheetrock pieces on top of the drop ceiling, which is done often.
 
Sheetrock installed in audio sensitive areas is generally separated from the framing using tracking or flexible mounting methods, otherwise you're just creating a big soundboard to pass through the framing. Solid ceiling methods need to isolate the structures to prevent the sound from transferring, not to mention a sheetrocked ceiling is going to make the room much more "live" and bright compared to a drop tile ceiling, which needs to be factored in to the audio profile.
 
A drop ceiling allows mechanical access, physical modifications and the addition of more insulation (IE: fiberglass or rockwool) that slows and dissipates the sound waves faster than if it was being physically transmitted through the framing. Think about it, sheet rock on a framed wall with any volume behind it is just turning into a larger speaker (laminar driver). The biggest challenge for any audio or theater is always going to be attenuating the low frequencies because they are not directional.
 
To put it in perspective, I just finished up a Visual/performing arts college for the state and they have 2 theaters/auditoriums/stages, multiple studios-recording and broadcast/editing, and practice studios, all of which are soundproofed and certified. The theaters were tuned over a month's time by the engineers. Guess what is not being used as a ceiling material and what is installed?

 

[Neurorad]

Hehe, popcorn at hand, awaiting jautor's response...

For a home theater, drywall will win, sorry DEL.

Of course, hat channel or whisper clips are used for the double drywall ceiling, with R19 or rock wool above.

I doubt a drywall ceiling would be allowed in a commercial space.

 

[jautor]

Commercial spaces and large venues have very different requirements and issues than small, wood-framed residential rooms... Solutions and best practices for one doesn't necessarily transfer to the other.  Mass is one component, isolation from framing is another - both are important.  But again, I'll defer to the experts, and if the OP has any desire to add any measure of sound isolation to the room he's building, start by reading this:
 
http://www.soundproofingcompany.com/soundproofing101/
 
... and call Ted when you have questions.  If you're building a dedicated room, it's certainly at least worth doing the investigation.  The cost adder to do quite a bit of isolation may not be out of line, depending on the overall project budget.  But once the room is 'finished', it's too late to do much about it, so plan accordingly.  And remember that for home theaters, the isolation is as much about keeping sound OUT of the room as it is keeping sound IN the room.  
 
Jeff