
RICK FITZPATRICK
New member
Adding 4 inches of wall on each side, cuts down the room drasticly!
Hello 11miles.
No sense in wasting time on this untill we found out the materials available, and also, your next statement has a bearing too.
My point exactly. Why do you think I suggested more than one solution. Either room size is the governing criteria, or Low Frequency Transmission Loss is. One or the other, you can't have both in your room. It is a matter of trading off one for the other.
Without doing the calculations, I cannot tell you the difference in frequency at which transmission occurs in each type of solution. And frankly, the room as a whole really is the governing criteria, as the ceiling, and floor also relate as transmission loss in your situation is a matter of the entire room being enclosed by an exterior shell. That means your weakest link will govern the rooms transmission loss as a whole. Which in this case, means your ceiling, as you certainly can't afford loss of headroom by building a suspended ceiling with an airgap equal to your walls if you built stud walls with an airgap larger than 1" between the back of the stud and the existing wall(4 1/2"). So......
To me, it is a matter of compromise, which is what I told you from the beginning. To build a room to contain a db profile of 85 db down to 20 hz, would probably take an exterior shell of concrete TWO FT THICK! Remember, as a concrete BOX, transmission loss through your exterior shell will radiate in all directions as I believe the shell has it's OWN resonant frequency, but don't take my word on that, it is just for illustration sake.
See what I mean. It is relevant. Transmission at WHAT frequency and at what db from the source is the real question. In other words, if you were monitoring a song that had a bass line and drums thumping loudly, at what db level, would transmission occur? Well, that is one hell of a challange to actually predict correctly. Even for an acoustical engineer. That is why containment is really a matter of designing the entire structure so they CAN predict it by using TESTED assembly designs. In your case, well.....
We will do the best we can.
That is why Home Recording containment issues are at best happenstance and compromise. Unless you can afford to build from the ground up, with tested assembly designs, the containment performance is likely to be limited to a point.
As far as the HVAC is concerned, that is YOUR decision. The only thing you REALLY need is ventilation. We will work on that one. In the mean time, .....speaking of time, I am out of it at the moment. Talk to you later.
fitZ
Hello 11miles.
It is not the gap that makes it effective. Mass is. The gap has a bearing on low frequency transmission loss. The deeper the gap, the longer the air "spring", hence the lower the resonance of the assembly. But let me reaffirm my disclaimer. My understanding of this is very limited, but I think you will get the point. I will ask one of my friends who DOES know the actual calculations, but not till we determine what you can build in reality.How thick/wide, must e the air gap between the walls to become effective.
No sense in wasting time on this untill we found out the materials available, and also, your next statement has a bearing too.
THe problem is that if the gap should be any wider than an inch, i would beg to consider doing it. You see, the room is very small as it is. Adding 4 inches of wall on each side, cuts down the room drasticly!
My point exactly. Why do you think I suggested more than one solution. Either room size is the governing criteria, or Low Frequency Transmission Loss is. One or the other, you can't have both in your room. It is a matter of trading off one for the other.
Without doing the calculations, I cannot tell you the difference in frequency at which transmission occurs in each type of solution. And frankly, the room as a whole really is the governing criteria, as the ceiling, and floor also relate as transmission loss in your situation is a matter of the entire room being enclosed by an exterior shell. That means your weakest link will govern the rooms transmission loss as a whole. Which in this case, means your ceiling, as you certainly can't afford loss of headroom by building a suspended ceiling with an airgap equal to your walls if you built stud walls with an airgap larger than 1" between the back of the stud and the existing wall(4 1/2"). So......

"Soundproof is a MISNOMER". Even under the BEST circumstances, it still is rediculous. IF there were traintracks within 20' of your room, I doubt ANYONE could build a room that you would NOT hear the train.But i know that good sound proof wall prerequisite some space too.



As far as the HVAC is concerned, that is YOUR decision. The only thing you REALLY need is ventilation. We will work on that one. In the mean time, .....speaking of time, I am out of it at the moment. Talk to you later.
fitZ

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