Black Ice Theater construction

[qtiping]

Koaru,
I asked around about the effectiveness of gluing 2 sheets of Gypsum board together, and I was told that it would actually reduce the STC. I found an article that was written by a researcher at the NRC (National Research Council). It states the following

"When two layers of material such as wallboard are glued firmly together, they behave like a single thick layer with an associated lowering of the coincidence frequency. If the layers are only held together loosely (with screws for example) so that they can slide over each other to some extent during bending motions, then the coincidence frequency does not move to lower frequencies and the friction between the layers can introduce some extra energy losses."
link to article
http://irc.nrc-cnrc.gc.ca/pubs/cbd/cbd239_e.html

So you could save the cost of the glue, which you said was about $900.

Tim

[Kaoru]

Originally Posted by qtiping

Koaru,
I asked around about the effectiveness of gluing 2 sheets of Gypsum board together, and I was told that it would actually reduce the STC. I found an article that was written by a researcher at the NRC (National Research Council). It states the following

"When two layers of material such as wallboard are glued firmly together, they behave like a single thick layer with an associated lowering of the coincidence frequency. ...snip...

Thanks for the info... it is apreciated since I don't want to fork out $900 if I can avoid it. However, Green Glue is not a glue but a visco-elastic damping compound and as such is specifically for sound proofing/damping. As I understand it, GG can't and doesn't act like glue hence the dual layer drywall doesn't behave as a single sheet. There is alot of test results on its effectiveness and it is indeed quite effective. However, my concern is all the short circuits, flanking, conduction, and other issues besides the drywall. No sense doing GG if the sound will be transmitted another way or the sound is different in nature (ie. bass, impact noise, high frequency, etc.)

Cheers,
Ed.

[qtiping]

You are right that the short circuits through the resilient channels can be a problem however, it can be avoided by the installer is cognitive of the problem. Here is the link to the NRC's Acoustics research group website. They have quite a few publications, the "Sound Transmission through Gypsum Board Walls Phase One and Two" provide quite a bit of data on the STC's of different walls constructions.
http://irc.nrc-cnrc.gc.ca/ie/acoustics/index_e.html
They have also have an older document that talks about sound proofing a basement.
http://irc.nrc-cnrc.gc.ca/pubs/bpn/25_e.pdf

Tim

[Kaoru]

Well I made progress over the labour day weekend on two fronts. The first is I've framed the screen wall(s) side of the theater. The only framing left is the inner stud wall/door frame, the equipment rack, and the angled studs on the screen wall(s). Given that the framing is nearing complete, my attention now turns to the interior.

Of course, I'd post pictures if I could but my blogging server is missing MySQL. I uninstalled it thinking that I was cleaning up old apps. Actually, I maintenanced all my machines (Roger's is giving away Norton Antivirus; beats paying $400 for subscriptions). This leads me to the second front where I upgraded my HTPC and media server (NSLU2 or know as a slug). I overclocked (or more correctly deunderclocked) my slug to 266MHz, loaded the uNSLUng firmware, and added another 250Gb drive. Now it's a better media server.

So... my attention turns to the interior. Interesting enough I happened cross paths with a site about Silver Theatre, an icon of art deco architecture by theater architect John Eberson. I was intrigued with the interior elements; the side features and center soffit direct focus to the screen. This is similar to what I'm trying to accomplish and fits well into the unique layout I have. Also having a center soffit can solve some problems like ducting, wiring while NOT interfering with the ceiling height vs riser vs side isles. Also, I believe I can integrate Eberson-esque features on my screen sides and being able to eliminate columns via a "corbel" style (hides surrounds) similar to the screen sides. The only thing left is to find a style/theme (I like art deco but following Eberson's cloud/star decor is not original). I'm leaning towards a "dancing northern lights" theme.

If you ever saw northern lights up north on a clear cold night you'd have a idea of what I'm thinking; here's a picture (but it doesn't do it justice).


Cheers,
Kaoru

[Kaoru]

Well, it's been just shy of a month since my last post so I thought I would update the thread with some current pics. When I last posted I was waiting on my 200 amp service installation and I putting some thought to the interior for both sound proofing and decor/style.

As for my 200 amp service, Ottawa Hydro rescheduled it to Oct 11th due to rain (they don't do disconnects in the rain) which has delayed things. Because of that I continued with the framing and made some decisions regarding sound proofing. I looked into RSIC clips/channels, sistering joists, etc. as to decouple the ceiling. I'm still looking into the various options but I estimate that clips will run about $850 for the clips/hat channel. On the other end, sistering or seperate joists will cost about $350 in materials. In either case, it's alot of work and hard to judge whether it's worth it.

I'm wondering if I should go with just standard furring strips with FoamSeal/R multipurpose gasket. Note that I'm doing this for the stud walls where all the stud surfaces will have this closed cell gasket stapled on (the gasket is ridged). I've discovered that this gasket does effectively stop vibrations from some simple tests I did with two stud walls touching a steel I-beam; the one using the gasket the beam doesn't ring (just a dull thud)... the other one causes the beam to ring when the studs are hit with a hammer. (Note that this was a mindless/simple test) I'm interested anybody's comments, suggestions, opinions, etc. in using this technique.

Anyway, here is a picture of the current state... notice the pink foam gasket between the entrance studs and the I-beam (it may not look like it but anying touching the I-beam has the gasket). The pic shows the entrance (got to cut out the bottom plate after I anchor the frame) and the equipment closet (with a hallway/bathroom/bar behind it). The opening to the equipment will be shorter than shown (a baffled vent will be on the bottom) and with a glass door. The closet and entrance door will be solid core with door gasket/stripping.



The false proscenium where I still have to add some studs at the angles. This will require ripping some studs lengthwise at angles (to keep the decoupling). The screen will be ~20" from the back wall and there will be a sand filled (low-height) stage. The sub goes behind the screen... I'll be using french cleats (from the side walls) to mount the screen making it removable. The center speaker will sit on the stage (on a stand) just under the screen. If you read my previous post you can imagine the style I'm going for with some feature on either side of the screen (which will also house a curtain) and a center soffit on the ceiling (which will house cables/air ducts/returns). This removes the ceiling height issue in the back (ie. having a ~8" riser step and a 8" corner soffit with a 7' 8" ceiling space). It also hides the projector and simplfies my ducting.



That's it for now...
Kaoru

[Kaoru]

Finally my 200 amp service was installed on Monday after another delay due to rain. Now I have enough breaker slots to wire the basement which means I going to commit to purchasing the necessary fixtures, boxes, Grafik Eye, etc. to do all the wiring including the home theater (which is the driver of my efforts). I'm curious on how many circuits to devote to the theater and whether or not I should install a surge suppressor. Ideas/comments welcome... My current train of thought is to put several inline outlets in the equipment closet on dedicated circuits. The question is how many circuits should I use?

Also, I've nearly completed all the framing and have begun putting in the duct work. I'm going to use 3 1/4" x 10" stack/box ducts going down the center of the theater. This allow me to provide two returns (with 4" take offs) on the return stack and two supply (also with 4" take offs) on the supply stack. As it works out the supply registers will be in the front and the returns in the theater rear; this means a single line for the stack ducts. The only detail I haven't figured out yet is the projector box/mount since the stack duct is in the center. It poses no problem for the projector itself, it's just the wiring, beam mount point, etc. that has to go somewhere. My initial idea is to build a projector box with the return duct integrated somehow. Hopefully, I'll have some pics to show the effort to date, as well as an updated floor plan.

Cheers,
Kaoru

[rwalker]

Kaoru,

Since you have plenty of circuits available on the new panel, a bit of over-supply isn't a bad thing.

Run a single circuit to the projector area to service that. This is over supply but you have the circuits.

Each circuit is good for 15 amps. Look at the equipment in your rack and add up the current draw per unit you expect to put in the rack. For every 10 amps of equipment you intend to put in the rack, run a single 15 amp circuit. This will leave plenty of overhead.

In the equipment room beyond the rack circuits, place another couple of dedicated circuits. This will be easily more than you need, and a safe number. This does not include lighting etc. though. That's seperate.

All A.V. circuits should draw from the same phase of your electrical panel. It's tempting to use sequential breakers, but this means every-other circuit in the room is on the other phase. This could potentially setup inter-equipment potential (voltage) and increase electrical noise in your system.

Put your lighting, fans, popcorn maker, micro-wave, fridge etc. on the opposite phase to the A.V.

I'm ambivalent on the topic of a surge suppressor so I'll let others chime in. I also don't have a good picture on your duct-work vs. wiring issue.

[Kaoru]

Originally Posted by rwalker

...snip...
All A.V. circuits should draw from the same phase of your electrical panel. It's tempting to use sequential breakers, but this means every-other circuit in the room is on the other phase. This could potentially setup inter-equipment potential (voltage) and increase electrical noise in your system.

Put your lighting, fans, popcorn maker, micro-wave, fridge etc. on the opposite phase to the A.V.
...snip...

This I didn't know and is something that I will definitely discuss with my electrician when I rough in the wiring. I assume from the above that I will have to pick the phase that has the least possibility of electrical noise. This may be tough though given everything that will be connected (ie. furnace, fridges, stoves, hot tub, AC, etc.) which may span (or pepper) across the phases. As for the layout of the ducts, I'll be post another CAD layout with the dimensions, wiring, ducts, etc. when I get the chance.

Cheers,
Kaoru

[rwalker]

Yea, it's really impossible to get it all. The most important part is to put your A.V. on the same phase to reduce the possibility of inter-device problems.

Most of the time, even on opposite phases you'll be fine. It's a matter of giving yourself the best chance.

Transformers, rectifiers and filters in the device power supplies fix most problems.

[Kaoru]

I still had some work to do on the outside... reconnect my old Bell phone demarc; not that I use it anymore and I took a gander at my new digital meter (Ottawa Hydro is switching over to time-of-day rates in the near future; another money grab). It states that the input is 200a Single Phase 3 wire... is it possible that I have only one phase?

Cheers,
Kaoru

[rwalker]

Phase is the probably the wrong word. I mean opposite sides of the panel. From your previous post it's clear you understand it because you mentioned the stove etc which is 220 volts and spans both feeds.

The 3 wires are 2 "hot" feeds of 110 volts each and one nuetral. You get 110 volts from each hot to nuetral and 220 volts between the 2 hots. Because these 2 hots are "180 degrees out of phase" with each other, I use the term phase. This is single phase to the electrical system though.

Sorry for the confusion.

[GQUEUE]

Ron,

Can you give examples that you've seen where having outlets on opposite sides of the split on interconnected AV equipment have an impact? I am curious as to what type of symptoms you might encounter. I would have thought that most AV equipment these days rectifies the incoming AC into DC, so the AC phase is mostly irrelevant.

Kaoru,

Have you considered the positioning of your HVAC ducts and returns? Just wondering if you gave any thought to the fact that the projector will be likely blowing a lot of hot air out and as such, in the summer time you would want that being sucked right into the return, where as in the winter time, you might want that flowing into the room. I have seem return vents at the top/bottom of a room with louvers to open/close them according to the season. Perhaps you might want to consider something similar? Just a thought.

[Bent]

In a single phase 120/240v system, we refer to the "phases" as "legs" - but I knew what was meant anyways.

[rwalker]

You are absolutely correct when you say "most AV equipment these days rectifies the incoming AC into DC, so the AC phase is mostly irrelevant".

It's unlikely to cause a problem, but we like to minimize the likelyhood of problems such as ground loops etc. It's the same as providing dedicated circuits. But these dedicated circuits are only dedicated between the panel and the receptacle. The reality is that they are unlikely to make a difference, but we use them to minimize potential problems.

To be honest, the only first hand example I have is from when I worked in computer field engineering. Occaisionally we'd have inter-cabinet data comm problems and found that we could solve them by ensuring the cabinets where on the same side of the panel. These cabinets usually had a dedicated circuit each. Often those dedicated circuits came from adjacent breakers so where from oposite "phases".

This happened in short cable situations. In longer situations, when the cabinets where in other rooms or buildings it didn't happen becuase then we'd use modems or balanced cabling which eliminated the ground reference.

In A.V., this noise between the "phases" could cause hum in analog audio, or interferance on analog video. Digital audio and video can eliminate this noise, but not necessarily.

Which reminds me that if we have a choice, and with low to mid level consumer gear we never do, we should use balanced interconects. These are the "XLR" style we see on pro gear, microphones etc. They eliminate a lot of noise problems. You get this with gear such as Bryston and others at that level.

So, to summarize, if I have a choice I try to have all A.V. gear on the same side of the panel. I don't think not doing this is highly likely to cause problems, but want to minimize the likelyhood of problems.

[plummer]

Man.....i've been watching this thread for a little bit and COOL. I am also in the process of framing/wiring my basement.
Some notes i will make comment on:
- as for the vapour barrier......em is probably correct....however this has seemed to change so much over time....and nobody can give a straight answer anymore. I originally thought that VB all the way to the floor was the way to go....but the other way makes sense too. So do what you think is right...and live with it. Cause i can guarantee what you do now.......will change in 5 years anyways.
- the walls. I can't see them floating. Might not have heaving in your area....but where i live in Saskatchewan.....it is a necessity to have the walls floating!
- the HTPC..is very nice. I am just in the process of getting my parts for mine. Will be similar (in some ways) to yours. Can you expand on a little on setup and stuff? I am a techy....but not sure which route to go for this.

Otherwise......looks great and i will eventually post pics of my basement for comments. Nice work!