After months of lurking on this forum, I'm ready to start construction of the...
which is going to be constructed along with the rest of the basement:
The inside of the theater will be 20.5' x 15.6' x 8.5', but that doesn't include the bump-out in the back for the projector or the bump-out in the front for the center speaker and subs, which will be behind an acoustically-transparent 2.35:1 screen:
I think I'm ready to pull the permit but, before I do, I was hoping to get a nod from you to go ahead. For the permit, I'll only use the entire basement layout picture above, which doesn't say much about the theater area other than where the walls are...and therein lies my first question - will I have enough sound proofing/isolation?
Specifically, note that the three poles (blue circles) and the concrete walls constrain my space. I'm very willing to let the interior walls be extra thick as it lets me stagger-stud one and double-wall the other, while hiding the PJ and rear speakers inside it. The walls against the concrete will be 2x4 framing with 2 layers of drywall with Green-Glue between. Also, note that the 2' wall near the front-left speaker will have its 2x4 studs laid flat, but it will still be DD+GG.
So, what do you think, do you see any issues with this design?
PS: in case you are wondering, I was down in the basement a few months ago looking things over and trying to come up with a name for the theater when I noticed my cat, who is black, lounging in the middle of the taped-out floor
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I agree that dricore would take care of it. Regardless of carpet choice if you do get water that goes above the dricore you will need to pull it up. I too got water and was able to salvage my carpet in the HT but it was not an easy task. The dricore and the padding did need to be replaced.
I spent the better part of today researching at the DRIcore product and others like it. Interestingly, most google searches link back to AVS Forum
Things I don't like about DRICore:
it has a glued-on OSB layer. So, not only is OSB an organic product that can break down and/or mold when wet, they also made it very difficult to remove the water that might be trapped in the dimples on the top-side
it's thick! - almost an inch... If only doing the theater room, I'd have to have a ramp at the door to transition to the adjacent room *and* I'd likely have to put another layer of OSB on my riser (so the 2nd row can continue to see over the first)
After reviewing nearly 10 products like DRIcore, I think I like SuperSeal's Carpet Subfloor Membrane the most. It's only 1/8" an inch, has no organic matter and, unlike Delta FL, doesn't require a plywood to be put on top of it, since its dimples are too small to be felt under a normal carpet pad. On the downside, it only offers 1/16" of an air-gap, whereas DRIcore has 3/8" gap, but my thoughts are that it's OK for what I care about (to keep a wool carpet dry).
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If you go dricore you can save some money by also building the riser directly on the concrete and simply dricore the section in between. That's what I did and it really worked out in my favor. I did use pressure treated lumber as the base for the riser and stage, as it appears you also did for your stage.
I already have walls, stage, and riser in place - so this is my only option but, looking at Logan's thread, I'd be disinclined to put DRIcore under any of them!
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Originally Posted by BeerParty /forum/post/21725753
Since you are planning to finish your entire basement, are you planning to put in a dehumidifier? Even with a dry basement, summer humidity + cool basement will produce issues. Assuming you used standard building materials for what you have done already (re: drywall and insulation), you may have to invest in a dehumidifier anyway.
Already have a dehumidifier. Got it to help dry out the sand I put in the stage. Seems like good practice to run it during summer months. I might run it year-round - ideally it'd be hidden out of the way in the theater room, but the only hidden spot is behind the screen. Hey, BIG, I'm having an idea for a trick access panel...no, no, no, you don't need to put you head in the dead vent again...
No, I meant, how did the water get in in the first place - cracks in walls or foundation, a bad window, what? My house is ~5 years old, built by a reputable builder, and bone-dry since day #1. I'm paranoid enough to install SuperSeal, but I think it's unrealistic to plan for 5-6 inches of water - that's what insurance is for.
It came up from the sump pump well I believe. His basement entrance is the same as yours with a below grade stairwell that acts like a rain collector. At his place that drain at the bottom of the stairs connects inside the house to the sump well.
It looks like you have a sump so if it's tops pumping, it will eventually overflow.
The water in the sump comes from the water in the ground outside your basement walls. To keep the water from seeping through the walls, most basement walls have a waterproofing membrane applied with drains at the bottom of the walls. The water looks for the path of least resistance which is the drain. These drains are then piped to the sump which pumps it away from your house.
If your lot has enough slope, you just run the perimeter drains out to daylight and let gravity do what it does best. If you have a flat lot, or your basement is the lowest point, you pretty well have to put in a sump pump.
Yesterday, BIG and I put a layer of 5/8" drywall on the dead vent we built last weekend. We used a whole tube of GG to dampen the four visible sides...well, three sides and the bottom. As we finished, I rapped my hand against it to see how sturdy it sounds. While my raps sound like thuds, I also noticed that it sounds a bit like a hallow box.
Before this gets out of hand, I should quickly amend that the dead vent sounds just like my walls, which *are* stuffed full of insulation. I'm no longer concerned with the hallow sound, per se, but I still wonder if we inadvertently created a "boom box" that could affect sound quality. I can setup my speakers and test, but what should I listen for? - muddy bass? If I use REW, is there a particular tell-tale pattern to look for?
Went to Jo-Ann fabrics yesterday. The only 1" thick poly-fil batting I could find is labeled "densified batting" - more specifically Soft-n-Crafty NU-foam, by Fairfield . It looks and feels like batting, albeit it seems more stiff (less soft). Is this stuff OK to use, or will it have more absorption than regular battling?
I searched AVS forum, there are no references to densified batting in any of the results...
Following this scientific make/measure/remake approach the columns can only be temporarily set in place as well.
Or we could install columns and molding make all the panels friction fit (removable) and just set in place for testing, if they fail pull off the wall and re-stuff. After you are pleased we would need to attach the panels to the wall.
Or pay someone for an acoustical treatment plan and build it once.
Some pictures from the weekend
Furring on the wall and Linacoustic
After trying the see through test we decided that the furring should be painted a dark color so that the contrasting light wood and black Linacoustic wouldn't show through the fabric.
With the real fabric, carpet sample, swatch of the proposed soffit paint, scrap of birch plywood (it will be stained cherry)
Sorry, just getting back to this thread (I had a busy week in my theater, but I'll update with pics tonight).
The house was built around 1990. I'm behind the Kohls across form the NoVa campus off Rte 7. As near as I can tell the water came up through the pit and then flooded over the threshold of the sliding door from the outside because it wasn't draining into the pit any longer..
The first time, pretty simply, the sump pump failed. And there was a LOT of rain REALLY fast. I was out of the basement for 90 minutes and it went from bone dry to ankle deep. So I put in a back up.
The second time, I think what happened is that the float of the primary pump got caught up in the additional wiring of the back up and never turned on. It worked fine when I reached down in there and lifted the float up into position. Then I think that because again there was SO much water so fast that the backup was running continuously and the battery died. The problem there I think is that I think need a new battery already because THIS time the flood happened over about 25-30 minutes from the time my son left the house and actually checked it and the time my wife got home and found it. The water wasn't as deep as we got there sooner.
THIS year I'm thinking of two things. A temp cover over the steps from about the last week or so of August (BOTH floods were the first week of Sept) and setting a new sump pump at the bottom of the steps with one of the floats that slide up and down (as opposed to the floating bulb type) set to come on with as little water down there as possible.
I think the only permanent solution I've come up with is to see if I can find someone that can horizontally drill a hole and install another drainline from the bottom of the stairs out to the storm drain just outside my property line. Without having to take out a 2nd mortgage, that is.
Taking a break, sitting on the riser, I noticed that the chair rail might be close to a reflection point. Breaking out a mirror, it seems that, at it's closest point, it's 3.5" away from a speaker's lowest woofer. Taking into account the 1.5" furring strip, the reflection point is about 2" from the closest hard surface. This is for the "far" speaker - that is, the speaker on the opposite side of the room from the listener. The direct line-of-sight distance is 170", the distance including the bounce off the wall is 283". So what do you think, too close for comfort? If "yes", then how many inches away do you think it should be?
BTW, wouldn't the untreated ceiling be a worse offender? I'm thinking this might be the case since: 1) all three LCR speakers reflect to the listener, 2) every driver of every speaker reflects to the listener, and 3) the reflection distance is closer than the "far" speaker bounce mentioned above. That said, the one positive thing about a ceiling bounce is that it comes from the same horizontal direction, but I have no idea how important that might be...
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Originally Posted by Morph1c /forum/post/21739446
Taking a break, sitting on the riser, I noticed that the chair rail might be close to a reflection point. Breaking out a mirror, it seems that, at it's closest point, it's 3.5" away from a speaker's lowest woofer. Taking into account the 1.5" furring strip, the reflection point is about 2" from the closest hard surface. This is for the "far" speaker - that is, the speaker on the opposite side of the room from the listener. The direct line-of-sight distance is 170", the distance including the bounce off the wall is 283". So what do you think, too close for comfort? If "yes", then how many inches away do you think it should be?
BTW, wouldn't the untreated ceiling be a worse offender? I'm thinking this might be the case since: 1) all three LCR speakers reflect to the listener, 2) every driver of every speaker reflects to the listener, and 3) the reflection distance is closer than the "far" speaker bounce mentioned above. That said, the one positive thing about a ceiling bounce is that it comes from the same horizontal direction, but I have no idea how important that might be...
These pics illustrate the reflection points - taking into account "angle of incidence is equal to angle of reflection" and relative travel distance. I also confirmed all these points using a mirror:
The YELLOW above/below the chair rail represents the furring strips. The little PURPLE hash-marks represent the reflection for each of the speakers drivers. It's the lowest hash-mark I'm wondering about. I think I'm OK, since it does go into the Linacoustic, but I'm asking since it's *so* close...
You guys started talking about floods and sump pump failures and it scared me witless! Sump pump failures make me shudder, cuss, and extremely paranoid. Actually ANY water issues in the house make me paranoid.
Really liking the colors. On the reflection issue I would not guess it would be that big of a problem, but I know NOTHING about acoustics so don't listen to me.
Right now I'm trying to decide if we're going to have to lower the chair rail a couple inches. I have a separate top-level thread discussing it. It's almost a good thing BIG was in Ohio, as it gives time to suss this out..,
In other news, Mrs. Morphy and I went to some carpet stores to see what options are out there. This frustrates me to no end as, seeing how so many struggle with carpet selection, we decided on carpet first, and then ordered the fabric to match, but now we're in the same predicament as countless others - ugh!
We found some multi-colored Friezes that matched our fabric selections pretty well. But before bringing home samples, we want to get the ceiling and a wall section done. It should be easier to judge with the correct lighting and a larger FOV to consider. The Bitterman carpet is not ruled out yet, we just want to see if we can find something synthetic that we're also happy with.
Mrs. M. and I are going to watch Hunger Games at the local IMAX theater tonight - woohoo!
It is hard to believe that between Morph1c and I we haven't posted any updates to this thread. I think I have at least three chapters to add.
First the CHERRY
Morph and the design committee decided that the trim work and columns should be cherry. So we found some at Smoot lumber, A bunch of cherry veneer plywood and some real stuff and we went to work making molding and columns:
so we had this air return that really sucked, and it sucked really loud.
So we formulated a plan
we cut it out and cut open the ceiling and built a huge air plenum/duct muffler
Basically we took a 6 inch duct to 8 inches, stuck it into the middle of a 14 ft long Linacoustic lined box and them cut in two 12 x12 inch return vents at the ends of the box. The box hangs on clips and channel and does not touch the ceiling joists.
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Originally Posted by BIGmouthinDC /forum/post/22028590
Basically we took a 6 inch duct to 8 inches, stuck it into the middle of a 14 ft long Linacoustic lined box and them cut in two 12 x12 inch return vents at the ends of the box. The box hangs on clips and channel and does not touch the ceiling joists.
The important thing is that all the work paid off - the new return is very quiet!
While it completely sucked taking down a perfectly good ceiling, it would've sucked more to always feel like I was on the Starship Enterprise. I'm very happy to have done this.
Are you still using the same fan you chose originally or did you end up changing that too? Was the noise mostly from the vents or was there some fan noise you had to deal with as well?
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Originally Posted by ozziegt /forum/post/22029069
Are you still using the same fan you chose originally or did you end up changing that too? Was the noise mostly from the vents or was there some fan noise you had to deal with as well?
Still using the same fan - the whisperline 340. Actually, I now have two of them - one pushing air in on the supply line and another pulling air out on the return line. It's still 340 CFM, which is more than enough air exchanges for the size of my theater, but I had to overcome the "head" (static pressure) in the supply line due to the flex duct twisting and turning. I probably wouldn't have needed the extra fan if my supply line was 12".
The noise was from the vents. 340 CFM thru a single 6" duct was a lot of air-velocity (~1700 FPM). This new configuration replaces the single 6" with the equivalent of two 12" ducts, which drops the air-velocity down to ~215 FPM (I think). For details, see my other thread "How do room treatments affect air-turbulence noise?"
Despite their name, the Whisperline fans make a noticeable amount of noise. Mine are located outside the theater, such that they're not audible with the door closed. Still, they're a bit obnoxious outside the theater and so I plan to suspend them from bungie cords, surround them with insulation, and patch the holes in the ceiling where they are (currently, their noise is directly exposed to the space below them)
PM me if you want to come over for a listen...
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