Unfortunately, I dont have a copy of sketchup. I could likely get a copy, however, if you think it's a necessity.
Naah, you can't afford it, I'm sure. Really expensive!!!! (Actually, it is free. You just download it direct from Google.
:) )
It's a great tool for planning your room. It takes a bit of getting used to, but once you "get it", its a very powerful tool. I'd recommend it. It will save you many problems and lots of money. Building a model in 3D on a computer is MUCH easier than building the real thing, and you get to examine it from all angles, even ones that would be impossible in reality. Moving a 3D wall around because you got it wrong, takes a few seconds a costs nothing. Moving a real wall around because you got it wrong, takes days and costs plenty!
I'll definitely pickup a set of those Hands Free Drywall Cleats from Amazon. They look to be a real life saver. I notice they have screws in them.. I'm assuming the cleats screw into the stud, supporting the sheet until fastened and then the cleats are removed?
The kind of cleats we are talking about here are just strips of wood that you nail diagonally into the studs, to hold the drywall in place.
This thread might interest you:
viewtopic.php?f=2&t=9127&p=63697&hilit=cleats#p63697
This one too (the discussion on cleats starts about one third the way down the page):
viewtopic.php?f=2&t=9091&p=63644&hilit=cleats#p63644
Search the forum for "cleats", and you'll find more than you ever wanted to know about them!
For instance, viewing the first photo I attached above, you'll notice that the space I'm isolating is only a section of the entire barn/shed structure. Opposite the left side of the opening, I'm isolating, is a storage area. You can see how I have the ladder above this storage area. The ladder is laying ontop the storage areas ceiling. The right side also has a similar storage area. You can see this in the 3rd image, attached above.
Does any of this create a third leaf?
Yes, and no! Probably not the answer you wanted, but it's the truth. I asked the exact same question here a couple of years back, and it took me a long time to understand the answers. so I'll see if I can explain it in simpler terms, noe that I finally get it:
You need to realize that a 2-leaf wall (MSM) is a tuned system. It resonates at a specific frequency that is governed by the total mass of the leaves and the depth of the air cavity in between them (among other things). If you increase the mass, or increase the air gap, then the resonant frequency will be lower. The idea of building a 2-leaf wall in the first place is to design it such that the resonant frequency of the wall is way below the range of human hearing, or at least is below the lowest frequency that needs to be isolated.
Now comes the fun: If you add another leaf to the system, contrary to intuition, that INCREASES the resonant frequency, driving it back up into the region that you were hoping to isolate. However, the effect of that third leaf once again depends on mass and air gap. If the mass is high enough or the air gap large enough, then the final resonant frequency of the entire MSMSM wall is still below the region of concern. So, if the third leaf is just a sheet of drywall two inches away from the existing 2-leaf wall, then there is a very large increase in the frequency, and your low frequency isolation is shot to hell. But if you put a 12 inch thick granite wall 20 feet away, clearly there is no discernible effect at all!
So, the question is, at what point does that "third leaf" not matter any more? the answer is obvious, when you think about it: at the point where the resultant resonant frequency is still less than half of the lowest frequency that you have to isolate. As soon as the gap is small enough / mass low enough that the final resonant frequency gets to be more than half of your lowest isolation frequency, then you have a problem.
So, for example, say that you design your wall to isolate from 30 Hz up. To do that, it needs to have a resonant frequency no higher than 15 Hz. You did a good job, and the wall actually resonates at 14 Hz. Great! Excellent isolation! Then you accidentally put a third leaf next to it that increased the resonant frequency to 25 Hz. So now your wall will not isolate at all at 30 Hz, and will in fact INCREASE the transmission at that frequency. Not only does it no longer block sound at 30 Hz, it actually HELPS sound get through, and does not isolate at all well until 50 Hz.
So let's say that instead of increasing the frequency from 14 to 25, your third leaf was a long way away and very massive, so it only increased from 14 to 15 Hz. Double 15 is 30, which is what you originally wanted, so that new massive distant 3rd leaf did not really affect your isolation at all.
It's not that simple, of course, but that's the general idea.
Unfortunately, the math for figuring out the resonant frequency of a 3-leaf wall isn't simple at all. However, I'd say that as long as you have a large amount of mass in your two-leaf wall (as compared to the third leaf) and several feet of air gap between the two-leaf wall and the third leaf, then you should be OK.
So that's a very long and winding road that leads me to say: Yeah, your other walls are third leaves, and no, they probably don't matter.
:)
However!!!! Now consider this: a kick drum can easily produce a fundamental tone at 80 Hz, or even lower. A bass guitar goes down even lower, to ... what frequency? Look it up, and shock yourself. You have to build a wall that will stop those frequencies. It ain't easy...
OK.. Gotcha. This dampens the inner wall, right? So If I were filling half, I would want the insulation against the inner wallboard?
It damps the cavity, not the wall surface. You can put it on one side, the other side, or both sides. It doesn't make much difference. It damps resonance in the cavity primarily, not so much resonance in the leaves.
haha.. i had no idea that drumkits are amongst the hardest instruments to isolate
Yep! You sure know how to chose your instrument, don't you?
:)
A drum kit can easily put out 115 decibels (C curve, slow response), even when played normally. You can get it close to 120 dB if you really smash it hard and fast. At 115 dB continuous exposure, the Occupational Safety Hazard Organization council says that you have about 7 minutes before you suffer permanent irreversible hearing damage. At 120 dB it's is more like 3 minutes.... Which, of course, explains why many drummers are partially deaf (those who don't wear ear plugs while playing).
And no, that isn't a joke. It is dead serious.
So yep, a drum kit is LOUD. Really loud. It also puts out a large chunk of that energy in the low frequency end of the spectrum, below 300 Hz, which is also the hardest part of the spectrum to isolate. Stopping a sound wave with a frequency of 20 kHz (top end of the spectrum) is a piece of cake. Even thick paper will do that reasonably well. After all, the entire wave is only 1.7 cm long. But stopping a wave at 20 Hz is a big deal: At 17 meters long, that wave is one thousand times bigger, and it will go through several inches of plywood without even noticing it too much....
To stop a low frequency wave takes quite some effort! It ain't easy. You have to do it exactly right, or it won't work.
Think of it this way: A bullet proof vest will easily stop an air gun pellet, but it will not be very successful against a cruise missile! It takes just a bit more armoring to stop a cruise missile (equivalent to heavy kick drum "thump"), than it does to stop a bullet (equivalent to faint triangle "ting").
You have to build your wall good enough to stop that cruise missile.
My Dad is a retired HVAC guy; He laughed at my idea to duct the unit.
If it wasn't designed to be ducted, then I can understand that! But I'm sure he'll get the idea of the exchange chamber. It's basically just a small room that the unit blows into, where it can make as much noise as it wants, and properly lined ducts lead to and from that room into the studio itself. The exchange chamber acts as sort of a giant plenum, and also a silencer at the same time. I'm sure your dad will get it.
Having said that, your Dad will also understand that the unit you have is probably NOT what you need, unfortunately, since it MUST be size exactly correct to deal with the exact flow rate, flow volume, and temperatures that will exist in your studio, under normal operation. If it is too big, it will move too much air too fast, and will cycle much to frequently to dehumidify correctly. If it is too small, it will not move enough air fast enough, will cycle way too slowly, and will wear out prematurely. It has to be sized right. You can't just put an engine from a 747 in your car and hope it will work, just because you got it for free. You also can't put your car engine in a 747 and expect it to fly.... things have to sized correctly to do the job.
Maybe a much better idea would to sell that huge HVAC thing and use the money to buy the CORRECT split system for your room, AFTER you and your Dad do the math to figure out what size it needs to be, based on room volume, occupancy, equipment heat output, humidity, etc. If your Dad is an HVAC contractor, he already knows how to do that. Or you can read Rod's book to figure it out. But is has to be dimensioned correctly.
His idea of creating a "partition" of some sorts, however, seems more laughable to me.
Well, the idea of a partition is the basis for how an HVAC silencer works: A series of many partitions, one after another, all covered with acoustic isolation and contained inside a large sealed box. The partitions force the air to gow around many corners like that, backwards and forwards, which helps to isolate and silence the duct. It's the right idea. Search the forum for HVAC and silencer to get an idea.
- Stuart -
