probably some old questions...

Eric_Desart · Post by **Eric_Desart** » Mon May 24, 2004 8:41 pm

Hello Steve,

You're doing as always a great job with your extensive explanations.

What I'm referring too, is the fact that I assume (for 99.9%) that this picture originates from:
http://www.customaudiodesigns.co.uk/articles/tloss.htm

This picture is extremely valuable.
I once said that this is either theoretically simulated (almost impossible to build in a measurement room) which should call for VERY clever guys, or measured which should make this a VERY expensive picture.
When theoretically calculated I even wonder if those numbers are really correct. I don't know of any model capable of doing this.
But that doesn't matter. This picture indeed explains the principle very well and as such is very valuable.

There is such a thing as Copyright, which means respecting other's people property and work.
The least is referring to the rightful source.

Now look to their site:
I just discovered that they put a watermark now trough ANY of their pictures, just to prevent this from happening.
This calls for unnecessary additional work for them, and make them ugly to see for anyone else.

I know that I wittingly withhold/held a lot of pictures, not putting them on the web for the very same reason. I start hating my own name, by trying to figure out how I can make a picture unusable and not destroying the graphics or making them unreadable.

I withhold calculators until I find a manner to protect the calculation procedures. Sharing standard things is one thing.
But if it toke half a year to find a solution it really is not that fun, this typical net behavior.

Proof?:
http://tinyurl.com/392d8
I'm an Excel expert.
I asked in Microsoft Excel groups if anyone knew a method to protect such calculation models.
I didn't got a response which is typical if nobody knows a solution.
Result: those models are still rotting in my CPU. And I don't think about releasing them. And I don't feel like specially studying C++ or Java or whatever, which can be better protected, just to help others (for free). And I want to help others for free, that's why I made them. I only have a huge problem with this anonymous distribution by others.
Credit belongs were it belongs.

Try to make a thesis in college, without explicit references to ALL sources. One is sacked before even the thesis is read.

I wanted to link to your thread here, as always VERY good, in the RO group, for somebody with soundproofing questions.
I wittingly didn't because of this anonymous picture.
So I just advised this guy to search for related messages of you and Rod.

I'm sorry.
This indeed extreme valuable picture does not belong on this site, at least not without VERY CLEAR reference to the source.
And one can as easy link to the real source itself, which can only add to the explanation.

Still as warm regards
AND lots of respect for your extreme valuable contributions.

Eric

knightfly · Post by **knightfly** » Tue May 25, 2004 1:35 am

Eric, I once had a link to the original, still looking and will post when I find it - I'm about 98% sure they claimed lab testing of all examples, but may be mistaken.

If anyone else reading this knows the origin of the wall comparison in the link I posted earlier, please let us know -

Here is the link, the pic is about halfway down the page -

http://www.johnlsayers.com/phpBB2/viewt ... =9704#9704

thanks... steve

AVare · Post by **AVare** » Tue May 25, 2004 2:18 am

If anyone else reading this knows the origin of the wall comparison in the link I posted earlier, please let us know -

Is this it?

http://www.domesticsoundproofing.co.uk/tloss.htm

Andre

knightfly · Post by **knightfly** » Tue May 25, 2004 8:34 am

This is kind of strange - Eric's link and Andre's link are both to the same company's sites, I knew they had an old and a newer nearly identical section but the wall pic in question doesn't show up (in my browser, anyway) in Eric's link, but DOES in Andre's - Also, no provenance is given for the graphic in either page, and I've seen similar illustrations on a US-based studio design site with more info - I seem to remember reading in one instance that each of these walls was actually TESTED at those values, but still haven't found that site.

Custom Audio Designs, however, might have more info, I may email them when I'm done with graveyard shifts this cycle to see what they have to say - Thanks, Andre, for posting that - I thought something was missing from the page when I followed Eric's link, but had forgotten that they have two nearly identical sites with different URL's... Steve

Eric_Desart · Post by **Eric_Desart** » Wed May 26, 2004 4:57 am

Hi Steve,

You know I do respect you a lot.
Your messages are incredible extensive and good (must cost lots of time).

But I think you know what I was trying to say.

Anyhow,

Warm regards
Eric

cadesignr · Post by **cadesignr** » Wed May 26, 2004 2:34 pm

Anyway, to my mind what you have is a single leaf wall, made up of 1" stucco (concrete, or close),5/8" plywood, 4" closed cell foam, slightly visco-elastic layer of construction adhesive, and another layer of 5/8" plywood - in all this, there is no effective air
gap but just different density mass layers with different coincidence dips - Again, I'm on "thin ice" here, if Eric differs with me we BOTH should listen

Hello Steve. If you ARE correct about this being one leaf, then why wouldn't the panel assembly I proposed not long ago, be considered one leaf. It was a sandwich panel of 1/2"MDF on both sides of a 2x2 frame, with the voids filled with CLOSED CELL injection foam insulation. Using 2 of these as a 2 leaf system with say a 3" airgap between lined with batt insulation., as the basis for a Vocal booth. Kind of like a crate within a crate. Ha! Anyway, just a thought. Easy to build though. Well, back to the shop. Later.

fitZ

knightfly · Post by **knightfly** » Wed May 26, 2004 5:17 pm

Eric, first I hope you are well - next, "But I think you know what I was trying to say" - I certainly do, and even though I sometimes forget to give proper credit when using info to explain a point, I would never take credit for the material of others - It's good that you remind us from time to time that it's also necessary to GIVE credit however - In this particular case, I'm still not sure of the origin of that graphic, although I've confirmed the probable STC ratings on the 2-leaf versions using the demo Insul sound isolation calculator. If/when I find the true origin of that graphic, I will post it along with the other "sticky"s" in this forum, since it really does make the case for 2-leaf walls - Other than that, what's your opinion as to whether these walls full of closed cell foam (described a bit earlier in this thread) could be considered one (poor) leaf or not? Maybe eventually I'll get my head wrapped around this concept

Hey Rick, long hair no time

- Yeah, I'm about 2/3 convinced that those walls would act as single leaves - I just have no clue how good they'd be, probably not very - there isn't enough mass involved for that. If I were starting from scratch, there is no way in hell I would do something untested and unproven like that, when Rod was good enough to post the link to the Canadian study of 300+ walls and their ACTUAL performance from which to choose - In fact, the foam on the inside of my (eventual) ICF outer wall leaves makes me a bit nervous, but since I'll be building inner leaves of triple gypsum and at least 8" air gap and the outer leaves will be 8" concrete, I doubt I'll have to worry about much getting through short of direct hits from mortar rounds

Gotta hit the sack soon, be happy... Steve

cadesignr · Post by **cadesignr** » Wed May 26, 2004 11:38 pm

when Rod was good enough to post the link to the Canadian study of 300+ walls and their ACTUAL performance from which to choose.

Hi Steve, thanks. I know your right. If you remember though, this whole thing was started by someone who wanted a knock down vocal booth. There is no way in heaven to make ANY of those assemblys knock down. Hence the crate approach. AND it has 2 full inchs of MDF, which compared to other vocal booth designs I've seen, is way more mass. But the proof is in the test, I agree. However, people build things all the time they are happy with, even though they don't meet the high ratings of tested assemblies. I was just trying to help one of the "homebuilt DIY" type members accomplish a vocal booth with the first criteria being "knock down", whether it met ABSOLUTE sound transmission loss criteria or not. 2" of MDF, in a "room within a room" floated design tells me something.

fitZ

oldguy · Post by **oldguy** » Thu May 27, 2004 1:33 am

I should probably point out that this 2" foam I'm using is actually open cell stuff. The NFH just put up a for sale sign on the house, so I may be fairly close to something that is actually functional.

knightfly · Post by **knightfly** » Thu May 27, 2004 1:54 am

Are you talking about the foam inside the walls being open celled? If so, then you already have both "leaves" of a wall system and we're back to trying to figure out how to improve isolation without more leaves... Steve