Building a new house around a theater, how to contain low frequencies? - AVS Forum
Forum Jump: 
Reply
 
Thread Tools
post #1 of 37 Old 11-05-2012, 08:16 PM - Thread Starter
Senior Member
 
Frosteh's Avatar
 
Join Date: Jun 2011
Posts: 304
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 16
Most of the research I've done regarding "soundproofing" a theater for low frequencies has to do with treating an already standing structure. None of these treatments really seem to work all that well, especially for containing sub-bass (<80Hz). So, my question is, what is the ideal architecture and construction to contain loud and low frequencies? And I mean really low, into the <10Hz category, for instance, since I'm thinking of putting a rotary sub in this new theater. We haven't finalized the architectural designs yet, but the theater will certainly be in an underground basement and will be 100% designed for soundproofing so as to not anger our neighbors.

Frosteh is offline  
Sponsored Links
Advertisement
 
post #2 of 37 Old 11-06-2012, 02:50 AM
AVS Special Member
 
Dingaling2004's Avatar
 
Join Date: Dec 2006
Location: Sydney, Australia
Posts: 1,131
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 8 Post(s)
Liked: 19
Suggest you have a chat to Ted White at the following company. I'm sure he will be able to offer you an expert opinion.

http://www.soundproofingcompany.com/

Good luck!

Follow my thread here
Dingaling2004 is online now  
post #3 of 37 Old 11-06-2012, 02:04 PM
AVS Club Gold
 
Dennis Erskine's Avatar
 
Join Date: Jul 1999
Location: Near an airport
Posts: 9,141
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Liked: 46
1. 10Hz can be reduced or eliminated....but, your budget and space needs to be huge (gross space, not net usable space).
2. with only one music recordings and perhaps less than seven movie titles with deliberate 10Hz content, you could save yourself a bunch of grief and a whole bunch of money by altering your criteria.

Dennis Erskine CFI, CFII, MEI
Architectural Acoustics
Subject Matter Expert
Certified Home Theater Designer
CEDIA Board of Directors
www.erskine-group.com
www.CinemaForte.net
Dennis Erskine is offline  
post #4 of 37 Old 11-07-2012, 01:51 AM
AVS Special Member
 
Nightlord's Avatar
 
Join Date: Feb 2009
Location: Southern Sweden
Posts: 1,815
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 312 Post(s)
Liked: 138
You need hard walls (as stone or similar) and as air-tight as possible if you are to be able to pressurize enough to play sub-10Hz with any noticable effect. Soundproofing as in dampening away any transmitted sound is close to practically impossible, so what is needed is rather to build in a way that you don't induce more vibrations in the room boundaries than possible. Problem with heavy is that resonance frequencies drop, so I wonder if it couldn't call for builiding a room within a room with the inner room being constructed with lighter walls that will have their resonances at higher frequencies.

If you're building a totally new place, why not do an entirely separate building so you'd only have to deal with air-transmitted sound, not structural vibrations?

Under construction: the Larch theater
Nightlord is online now  
post #5 of 37 Old 11-07-2012, 03:56 AM
AVS Club Gold
 
Dennis Erskine's Avatar
 
Join Date: Jul 1999
Location: Near an airport
Posts: 9,141
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Liked: 46
"hard walls" should mean very high mass.

Dennis Erskine CFI, CFII, MEI
Architectural Acoustics
Subject Matter Expert
Certified Home Theater Designer
CEDIA Board of Directors
www.erskine-group.com
www.CinemaForte.net
Dennis Erskine is offline  
post #6 of 37 Old 11-07-2012, 06:41 AM
AVS Special Member
 
Nightlord's Avatar
 
Join Date: Feb 2009
Location: Southern Sweden
Posts: 1,815
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 312 Post(s)
Liked: 138
Quote:
Originally Posted by Dennis Erskine View Post

"hard walls" should mean very high mass.

Yes, I know that achieving extreme LF and soundproofing against it calls for diverging properties. ( I'm going with a standalone building myself and hoping it won't leak so much that the neighbours will complain. biggrin.gif )

Under construction: the Larch theater
Nightlord is online now  
post #7 of 37 Old 11-07-2012, 08:48 AM
AVS Special Member
 
Ted White's Avatar
 
Join Date: May 1999
Location: Midland, MI USA
Posts: 8,186
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 33
Frosteh, there are limits as to what you can do in an existing building. You would still follow the 4 elements of soundproofing, however: http://www.soundproofingcompany.com/soundproofing101/4-elements-of-soundproofing-for-construction/

From a practical perspective, you'll want to at least consider three sheets of 5/8" drywall all around. Installed in a decoupled fashion.

__________________

Ted



The Soundproofing Company
Ted White is offline  
post #8 of 37 Old 11-07-2012, 02:43 PM - Thread Starter
Senior Member
 
Frosteh's Avatar
 
Join Date: Jun 2011
Posts: 304
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 16
Quote:
Originally Posted by Ted White View Post

Frosteh, there are limits as to what you can do in an existing building. You would still follow the 4 elements of soundproofing, however: http://www.soundproofingcompany.com/soundproofing101/4-elements-of-soundproofing-for-construction/
From a practical perspective, you'll want to at least consider three sheets of 5/8" drywall all around. Installed in a decoupled fashion.

And this is exactly why I am trying to sort this all out before I finalize architectural plans. The house isn't built yet, so I can go to every reasonable length to contain sound. When you say triple layer of drywall, do you mean going with a triple stud setup? I was under the impression that a double stud (room within a room) would be better and to simply make the gap between the two rooms larger. Is this not the case? Since the overall cost of a house is significantly more than the cost of a dedicated theater, we aren't holding back on the drywall and building materials we use. In fact, I'll even be decoupling the floor from the ground by lifting it with special blocks of foam intended for acoustic isolation.

For the record, I've read every one of the articles on your site; they were all very helpful. However, There really isn't very much on how to contain the low frequencies. To my knowledge and research so far, is the best way to isolate low frequencies inside the theater to simply make the gap between two rooms larger? Or is there another material or building practice that would waste less space? In theory, I could make the room within the room small and have the gap around the room gigantic, but this is cost prohibitive due to the space wasted to do so. How is concrete for sound isolation? I'm thinking that instead of only using wood and special acoustic drywall to make the inner room, that perhaps it would be better to build the room within the room using a second wall of concrete with a gap between these two walls. Then, build on top of that with a stud/drywall frame.

Frosteh is offline  
post #9 of 37 Old 11-07-2012, 03:20 PM
AVS Special Member
 
Ted White's Avatar
 
Join Date: May 1999
Location: Midland, MI USA
Posts: 8,186
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 33
Ideally, you'd stay with one impossibly massive leaf like 3 feet of concrete or such. Avoid the introduction of an air spring and a second leaf and you will specifically advantage the low frequency isolation of the system.

Nearly always however, we have to deviate from that optimal scenario, since no one builds medieval walls anymore (what have things come to...). We wind up with an initially lighter wall, like an 8" or 12" poured wall and adding wood / steel framing. Cool. Let's pretend we're talking about a wall.

Now we're looking at those 4 elements of isolation. We introduce a decoupled framing plan, like a double stud room-within-a-room or attach Clip&Channel to a single stud wall. We introduce some absorption into the stud cavities in the form of simple lightweight (fiberglass) insulation. Groovy.

For reasons we don't need to go into here, we want the low-frequency resonance point of this entire wall assembly to be as low as possible. All framed systems will resonate at some frequency, we'd just like that frequency to be at 15Hz compared to 80Hz. (examples only). This is because at or below the resonance frequency we can't isolate as well. Frequencies above this resonance point we can isolate well.

Assuming we have properly decoupled the framing and installed the insulation, you only have two variables that affect and define the low frequency resonance point of the system: the air cavity depth and the mass of that final leaf (drywall). Of the two variables, the added mass is the much bigger driver. You are better off adding a third sheet of drywall rather than adding many inches to the air cavity.

The last element, damping, does not assist with the establishment of that low frequency resonance point. Damping compounds reduce the severity of the resonance point, as well as all other frequencies up and through the high frequency Coincidence Point (that we don't care about).

So as I said previously, we generally just move to a third layer of drywall and leave the castle for the night.

__________________

Ted



The Soundproofing Company
Ted White is offline  
post #10 of 37 Old 11-07-2012, 07:12 PM - Thread Starter
Senior Member
 
Frosteh's Avatar
 
Join Date: Jun 2011
Posts: 304
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 16
So, in a nutshell, adding extra layers of drywall is the best thing you can do?At what point are the returns too low for the cost? 1, 2, 3 extra layers of drywall?

It seems that isolating all the way down to the low single digit frequencies would be too damn expensive to bother with, so we may just have to live with that and hope our neighbors enjoy earthquakes. What frequency is a reasonably goal to aim for in the LF section? 20Hz? 30Hz?

Frosteh is offline  
post #11 of 37 Old 11-07-2012, 10:09 PM
Senior Member
 
GIK Acoustics's Avatar
 
Join Date: Sep 2012
Location: Atlanta, GA & Bradford, UK
Posts: 220
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Liked: 27
I will agree with the experts in this thread..

10 Hz is an impossibly silly thing to want to contain. It pretty much won't happen...and as stated, practically nothing in this world has any 10 Hz information unless you deliberatly put it there. You may get a sub that has the capability to play 10 Hz (I've seen some large enclosures with extremely high wattage amps), but no music or movies will have information recorded that low. Even 20 Hz is extremely "down there" and hardly any movies or music have much information that low either.

If you absolutely need isolation at low frequencies, I would suggest doing yourself a favor and hiring an acoustic designer to design the wall partitions for you. You can come to an agreement on the amount of isolation needed and at what frequency. This way, you have a contractual agreement that he will get you there. This is important if isolation is important...since, if you do it wrong, or miss a piece, or don't think something is important - you will end up with not as much isolation as you needed. And in some cases, you can get no benefit at all. And from there you might have to tear down and restart. I've seen it happen...

With an acoustic designer, if he doesn't get you to what you agree'd to with him the first time, he will have to fix it on his dime. So you can rest assured you will get what you need. In the end, if isolation is a requirement, I feel a designer is extremely important..

However! If you ARE feeling up to the task and don't think you will mess it up, I would suggest grabbing Rod Gervais' book, Home Recording Studio: Built it Like the Pros.

Yes - it is written with studios in mind, but it has an extremely immense amount of information on isolation, wall assemblies, door assemblies, lighting assemblies, and how to make sure your contractors don't misunderstand extremely vital steps in construction that would weaken your isolation. Practically everything in the book is relate-able to any type of room - home theater, 2 channel, control rooms, recording studios, etc..

Alexander Reynolds
GIK Acoustics
GIK Acoustics is offline  
post #12 of 37 Old 11-08-2012, 12:17 AM
AVS Special Member
 
Nightlord's Avatar
 
Join Date: Feb 2009
Location: Southern Sweden
Posts: 1,815
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 312 Post(s)
Liked: 138
Well, if infrasonics interest you, then there are music to be found, but there are definitely more movies available the hits the 5-15Hz range. But it takes a lot to have any meaningful output in that range - the electronic boost needed to reasonably follow the shape of equal loudness curves is quite massive... so it will quickly turn into a grand collection of closed subwoofers with big, long-throw subwoofers to hit the pump capacity needed for the extreme-LF. Could very easily start costing more to go from 20Hz to 10Hz than what the rest of the setup costs...

A (/some) rotary sub(s) might to the trick too, but my spine thinks it will at the cost of higher distortion, so it'll probably need to be crossed over to normal subs rather low (20?) just the same.

Under construction: the Larch theater
Nightlord is online now  
post #13 of 37 Old 11-08-2012, 06:58 AM
AVS Club Gold
 
Dennis Erskine's Avatar
 
Join Date: Jul 1999
Location: Near an airport
Posts: 9,141
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Liked: 46
There is one, and exactly one, music recording of which I am aware (directly I might add) which has *deliberate* content below 20Hz. There are a whole pile of music recordings with sub 20Hz content. That content exists largely due to two reasons: (1) poor mix practices; and, (2) the <20Hz content could not be heard in the mix environment and therefore the potential of its existence was ignored (famously a recording where the London Tube ran under the studio). If you intend a system with the capability to play back <20Hz audible content, I suggest a DSP with a near brick wall filter at 20Hz to trash the unintended <20Hz junk in the recording.

As for movies ... there are some (very few) tracks with intended <20Hz content. It is unlikely that content exists on tracks noted "remixed for home use" (or similar).

I would suggest, you focus on a more reasonable isolation scenario, place those additional funds into more meaningful (and productive) items (electronics, speakers, projection system, acoustic treatments) giving you more bang for the buck. Let the neighbors eat cake for those very rare occasions where sub 20Hz material actually does vibrate something in their home. They certainly will not hear 10Hz (they may feel the vibration) and if they do, send flowers to their funeral.

All subs operate optimally in relatively narrow ranges. You will require multiple subs and sophisticated DSPs and very, very competent audio calibration.

Dennis Erskine CFI, CFII, MEI
Architectural Acoustics
Subject Matter Expert
Certified Home Theater Designer
CEDIA Board of Directors
www.erskine-group.com
www.CinemaForte.net
Dennis Erskine is offline  
post #14 of 37 Old 11-08-2012, 07:42 AM
AVS Special Member
 
Ted White's Avatar
 
Join Date: May 1999
Location: Midland, MI USA
Posts: 8,186
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 33
Quote:
Originally Posted by Dennis Erskine View Post

I would suggest, you focus on a more reasonable isolation scenario...

That's really what this all boils down to. 2-3 sheets of drywall has made thousands of theater owners mighty happy.

__________________

Ted



The Soundproofing Company
Ted White is offline  
post #15 of 37 Old 11-08-2012, 07:55 AM
AVS Special Member
 
Nightlord's Avatar
 
Join Date: Feb 2009
Location: Southern Sweden
Posts: 1,815
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 312 Post(s)
Liked: 138
Quote:
Originally Posted by Dennis Erskine View Post

There is one, and exactly one, music recording of which I am aware (directly I might add) which has *deliberate* content below 20Hz.

Well, if it isn't by Krumelur, then I can already now say you're wrong.

There are also organ recordings with 16 2/3 Hz pipes.

The sweep on the soundtrack of "Fifth Element" I believe to drop quite a bit lower.

There are definitely more than one. Or three.

Edit: Just stumbled onto Nitin Sawney - Anthem without nation, haven't measured it myself, but it's reported to play to 7Hz.

Swedish-russian artist CoH also has tracks going "infra".

Under construction: the Larch theater
Nightlord is online now  
post #16 of 37 Old 11-08-2012, 08:18 AM
AVS Special Member
 
Ted White's Avatar
 
Join Date: May 1999
Location: Midland, MI USA
Posts: 8,186
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 33
The point remains. A goal of isolating so low is fruitless and unnecessary

__________________

Ted



The Soundproofing Company
Ted White is offline  
post #17 of 37 Old 11-08-2012, 08:34 AM
AVS Club Gold
 
Dennis Erskine's Avatar
 
Join Date: Jul 1999
Location: Near an airport
Posts: 9,141
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Liked: 46
Yes. There are a very few number of organ recordings with C2. I'm not aware of any successful releases with C0 and C-1.

Dennis Erskine CFI, CFII, MEI
Architectural Acoustics
Subject Matter Expert
Certified Home Theater Designer
CEDIA Board of Directors
www.erskine-group.com
www.CinemaForte.net
Dennis Erskine is offline  
post #18 of 37 Old 11-08-2012, 09:42 AM
AVS Special Member
 
kromkamp's Avatar
 
Join Date: Jun 1999
Location: Toronto,Ontario,Canada
Posts: 4,409
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Liked: 25
Just out of curiosity - how much added mass is required to theoretically soundproof 10Hz vs 20Hz? (by soundproof assume increasing volume no more than 3dB outside the room)

Closer to 2X or closer to 10X?
kromkamp is offline  
post #19 of 37 Old 11-08-2012, 10:02 AM - Thread Starter
Senior Member
 
Frosteh's Avatar
 
Join Date: Jun 2011
Posts: 304
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 16
Multiquoting would take up way too much space, so I'll try and address some of the topics in the past 5 or 6 posts.

Regarding <20Hz content in movies, there is most definitely content in those ranges, especially in newer releases with the lossless tracks. Please do not take offense to this comment. In no way am I trying to say that any of you aren't experts in your fields (especially Dennis, who is regarded as one of the best in the world). However, I typically watch action flicks like Transformers, Black Hawk Down, How to Train Your Dragon, etc. If you're interested, there's a thread with a large collection of movies and waterfall graphs showing the frequencies of the soundtracks. Most of these have content to about 15Hz, many are below 10Hz. http://www.avsforum.com/t/755493/the-master-list-of-dvd-hd-dvd-blu-ray-movies-with-bass-thread-with-waterfalls.

For that reason, I'll be installing a rotary sub or two to play as loud as is necessary to reproduce those sounds. Music won't be listened to very much in the theater as we will have a multi-zone sound system for the rest of the house. However, taking what you have recommended, I should just forget about trying to isolate so low. I am open to the idea of hiring an acoustic engineer, such as Dennis or Ted, to design the room. However, I don't want to do so if we'll isolate down to a frequency that I could have designed myself. So, Dennis and Ted, what is a reasonable frequency to isolate to, knowing that I'll be watching these sorts of mega-bass movies?

Regarding my actual speakers setup, it is as follows: JBL 3731 >80Hz> 2x JBL 4645C >20Hz> Rotary Sub. I've got lots of experience with building and designing speakers, so this setup may change, but I think I'll keep it where it's at for now. This setup sounds incredible and is significantly less expensive than most commercial models advertised for home theater (85dB sensitivity for a $17k speaker? Give me a break!). I'm aiming for reference level audio at all frequencies. This shouldn't be difficult at all for these speakers in a smaller room.

So, let's add a couple building restraints so you guys can have a better idea of what's realistic for me to expect. Let's assume I go with the best materials out there (QuietRock 545?), I don't want the gap between the two rooms to be more than 12" (not including drywall, just the physical gap), and that I have the option of using concrete wherever you recommend, what do you think is a reasonable go to set for isolation at reference levels? And, let's assume we significantly reduce the internal ambient noise of the system, thus making it not necessary to play as loud and therefore not requiring as high an STC rating.

Thanks again for all your help, I really do enjoy learning and hearing from the experts.

Frosteh is offline  
post #20 of 37 Old 11-08-2012, 10:34 AM
AVS Special Member
 
Nightlord's Avatar
 
Join Date: Feb 2009
Location: Southern Sweden
Posts: 1,815
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 312 Post(s)
Liked: 138
Setup seems good to me, even though I have no idea of the jbls in question.

You seem to think the same about the extreme-lf movies as I do.smile.gif

My speakers are more like $10k, but they're at least around 94dB so I save a bit on amps. My goal is also ref level down into infrasonics.

Under construction: the Larch theater
Nightlord is online now  
post #21 of 37 Old 11-08-2012, 11:22 AM
AVS Special Member
 
Ted White's Avatar
 
Join Date: May 1999
Location: Midland, MI USA
Posts: 8,186
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 33
Frosteh, I would encourage you to consider using standard, rather than boutique drywall. Many reasons, not the least of which is cost.

a 12" air cavity is great. Install R19. Then three sheets of 5/8" drywall, or perhaps drywall / plywood / drywall so you have a nice nail base in there.

Kromkamp, if you want to start slowing down 15Hz frequencies, the fundamental resonance point of the would need to be 10Hz. Maybe 12 sheets of drywall on either side of a 2 foot deep decoupled wall.

__________________

Ted



The Soundproofing Company
Ted White is offline  
post #22 of 37 Old 11-08-2012, 11:55 AM
AVS Special Member
 
kromkamp's Avatar
 
Join Date: Jun 1999
Location: Toronto,Ontario,Canada
Posts: 4,409
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Liked: 25
Quote:
Originally Posted by Ted White View Post

Kromkamp, if you want to start slowing down 15Hz frequencies, the fundamental resonance point of the would need to be 10Hz. Maybe 12 sheets of drywall on either side of a 2 foot deep decoupled wall.

And what about 20Hz? (as a comparison)
kromkamp is offline  
post #23 of 37 Old 11-08-2012, 12:03 PM
AVS Special Member
 
Ted White's Avatar
 
Join Date: May 1999
Location: Midland, MI USA
Posts: 8,186
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 33
Andy, just as a comparison, you'd be looking at something a lot less, like maybe 4 sheets on either side. Don't take these as exact figures, only to demonstrate that the mass / resonance frequency isn't a linear correlation.

__________________

Ted



The Soundproofing Company
Ted White is offline  
post #24 of 37 Old 11-08-2012, 12:34 PM
AVS Special Member
 
kromkamp's Avatar
 
Join Date: Jun 1999
Location: Toronto,Ontario,Canada
Posts: 4,409
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Liked: 25
That is indeed a substantial difference! I suspected it wasn't linear, I just wanted to get a sense of how non-linear it was.

Last question - just roughly speaking, what is the resonant frequency of typical separate 2x4 stud walls/double 5/8" drywall/R19 construction? (I'm sure you have it somewhere on your website but just to have it here for context)

Cheers
kromkamp is offline  
post #25 of 37 Old 11-09-2012, 09:21 AM - Thread Starter
Senior Member
 
Frosteh's Avatar
 
Join Date: Jun 2011
Posts: 304
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 16
Quote:
Originally Posted by Ted White View Post

Frosteh, I would encourage you to consider using standard, rather than boutique drywall. Many reasons, not the least of which is cost.
a 12" air cavity is great. Install R19. Then three sheets of 5/8" drywall, or perhaps drywall / plywood / drywall so you have a nice nail base in there.
Kromkamp, if you want to start slowing down 15Hz frequencies, the fundamental resonance point of the would need to be 10Hz. Maybe 12 sheets of drywall on either side of a 2 foot deep decoupled wall.

What are the other reasons for not using boutique drywall? I was under the impression that there is a significantly higher mass in specialty drywall than there is in normal stuff you'd find at Home Depot. Is there really not that much of a difference between cheapo drywall and expensive stuff? In other words, would I be better off just adding a couple more layers of drywall with green glue between the sheets than using some expensive stuff? Like I said earlier, we haven't finalized architectural designs so there's definitely time to make the room a foot larger in every dimension to allow for more layers of drywall. This isn't a difficult feat to accomplish. If having 6 sheets of drywall with GG between them is what would be ideal, then, by all means, say so and I'll hop on it!

Frosteh is offline  
post #26 of 37 Old 11-09-2012, 09:52 AM
AVS Special Member
 
Ted White's Avatar
 
Join Date: May 1999
Location: Midland, MI USA
Posts: 8,186
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 33
Boutique drywall is made from materials purchased at Home Depot. You will always be able to build a more massive, less expensive highly damped panel in the field than you can buy pre-assembled. Always.

Andy, decoupled double stud walls with double drywall would have a MAM resonance point somewhere below 40Hz/ Likely 35. Labs can't even accurately measure that low and are only certified to 80Hz. I'm looking at lab data from Riverbank Labs.

__________________

Ted



The Soundproofing Company
Ted White is offline  
post #27 of 37 Old 11-09-2012, 10:14 AM - Thread Starter
Senior Member
 
Frosteh's Avatar
 
Join Date: Jun 2011
Posts: 304
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 16
Quote:
Originally Posted by Ted White View Post

Boutique drywall is made from materials purchased at Home Depot. You will always be able to build a more massive, less expensive highly damped panel in the field than you can buy pre-assembled. Always.

Gotcha. I was under the impression that they had some special high density compound they used in their drywall. With that in mind I'll just factor in some extra space and stack up the drywall. Wahoo!! Is there anything else besides using a double stud with a 12" gap and oodles of drywall that can add to the isolation? Or is that pretty much it?

My next question is about the doorway. Since the gap will be 12+ inches, depending on how deep I go with the drywall, how do I construct the doorway so that people don't have to jump to get into the theater? Would it work to simply build the framing for each door into the gap so that they meet in the middle? Not touching, but such that the gap between the two frames is small enough that I could just lay carpet over it?

Frosteh is offline  
post #28 of 37 Old 11-09-2012, 10:31 AM
AVS Special Member
 
Ted White's Avatar
 
Join Date: May 1999
Location: Midland, MI USA
Posts: 8,186
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 33
A little R19 fiberglass in that 12" cavity would be fine. If using multiple layers, get a plywood or OSB nail base in there to attach drywall to. Not all drywall layers. At this point, the trick is how much mass you can tolerate installing.

The doorway would simply be finished with field-fabricated extension jambs. Ideally you'd have two doors : http://www.soundproofingcompany.com/soundproofing-installation-manuals/sim-doors/

__________________

Ted



The Soundproofing Company
Ted White is offline  
post #29 of 37 Old 11-09-2012, 01:43 PM - Thread Starter
Senior Member
 
Frosteh's Avatar
 
Join Date: Jun 2011
Posts: 304
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 16
Do you fill the whole cavity or just the depth of the studs on each side? Most of the diagrams on your site only show the fiberglass going the depth of the studs, but I don't know if that's simply because most people don't deal with a 12" gap or if you actually need to fill the whole cavity.

And I'll definitely be using two doors. I know solid core doors are best, but how would a custom drywall/stud door work? As in, drywall on both sides of a stud frame to make up the door. It would be thick, heavy, and much less expensive than going with some $3000 custom door. This would also allow me to simply build it as thick as the number of sheets of drywall that my wall is.

Another thought is to build a custom door like that but fill it with sand instead of insulation. The density of sand is about double that of MDF and drywall and would make for a ridiculously heavy door. With some good heavy duty hinges and proper door seals, this seems like the way to go if mass is key. I could also just go all out and use concrete. Based on my calculations, I could have a ~530lb door using concrete inside an MDF frame or a ~360lb door using sand. See attached file for calculations. Then, using an automatic door stop instead of handles and locks, I could completely seal the doors. What do you think? This would be a relatively cheap door and heavier than all hell. door weights.xlsx 36k .xlsx file
Attached Files
File Type: xlsx door weights.xlsx (35.7 KB, 6 views)

Frosteh is offline  
post #30 of 37 Old 11-09-2012, 05:44 PM
AVS Special Member
 
Ted White's Avatar
 
Join Date: May 1999
Location: Midland, MI USA
Posts: 8,186
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 33
R-19 would be fine. If you'd like to go R30, you may as well. Most people use R13 because they're using 2x4 construction. You're bringing back medieval construction.

__________________

Ted



The Soundproofing Company
Ted White is offline  
Reply Dedicated Theater Design & Construction

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off