Originally Posted by aaustin
Exactly, so sound energy is changed to heat energy which therefore results in less sound being heard outside of the room. So soundproofing does not keep more sound in the room, it changes the sound that would normally leave into something that cannot be heard. Instead of sound leaving the room, more heat does.
I don't see how soundproofing results in more sound staying in the room.
That is only in constrained layer dampening and in the case of added insulation between the studs, but we know those are not the only pieces of the isolation system. These are small additions to the actual STC rating as a whole. Most of inherent isolation comes from mass, mass, and more mass. And the point is, low frequencies can penetrate thin partitions (thin in terms of low frequency waves) - but have a hard time penetrating hard, dense, heavy, thick material. I keep referring to concrete because its easy to imagine, but other materials can act similarly too. I remember Rod Gervais commenting on this previously with a good quote. I thought it may have been in his book, but I did a quick look through and couldn't find it. Perhaps he said it on another forum? Either way, I'll do some more digging and let you know if I do find it.
I suppose I should have been more specific: not every step of isolation will encourage sounds to stay in the room, but the main step of isolation - that is - mass, mass, mass...does encourage sound staying inside the room. Also in isolation, you try to remove any diffraction that could occur through vents, door frames, and other openings. When you create an air tight system, diffraction is not possible. Lastly, dampening flanking paths won't encourage any more sound to be inside the room than previously, but removing them could.
And I didn't find your posts to be unusually provocative - we all strive to learn - there is no problem there. I question other ideas similarly when I'm not sure.
Anywhoo, no point to dirty up this thread anymore with this. I'd be happy to chat with any of you over PM, perhaps we could find some cool links to share and learn more. I'm personally not an isolation expert - most of my knowledge when it comes to this is from books.
Originally Posted by Johnny14o
, great information. I will definitely keep it in the front of my mind as I move forward with the project.
- Consider the riser "Stuffed"
- Any voids I have in the false wall I will frame it up for the rest of the ROXUL I have.
- When everything is back up and running I will locate other places in the room for additional bass traps. One BIG concern is the back of the room, behind the riser.
The room meets the roof, thus has a taper to it. With this angle I can see it being somewhat of a "funnel" and focus a lot of sound waves into a pool of sound. I will have a cabinet (counter height) to the left and right with a built in desk top in the middle between them. I will definitely be reaching out to the forum for ideas on practical bass traps for this area.
Of course! Those points you make above are all good for covering - its good you are able to make for some other functional use out of that riser. The space in the back does seem like it could contribute some problems, but it will be hard to know without listening. It is a great spot for trapping though - out of the way visually, and we tend to see lots of bass build ups in the back of the room.
I will keep an eye on the thread and pop in again when necessary. Good work so far - keep up the great build!Edited by GIK Acoustics - 9/5/12 at 6:10pm