The 2 leaf system was proposed by Eric Desart when he built Galaxy studios in Brussels. The design was an Eastlake Audio (
http://www.eastlake-audio.co.uk/ea_news.html ) project but the client wanted one main recording room with 3 control rooms fronting onto it and they wanted 100db STC between all 4 rooms!!
Hello John, I forgot to thank you for your reply. However, read on. If I'm not mistaken, your "2 leaf system" statement above may be in for a bit of review. Frankly, untill someone clears up the term "leaf", I'm ready to chock all these years of reading up to a "a lesson in hindsight"
Now let me address andres last post.
Hello andre. Sorry it took a while to get back and thank you for the links. Actually, it took a while to analyse that document and then recover.
. I didn't see it before.
Acoustics, in studios is a very frustrating thing to fully comprehend because so little is intuitive, significant factors change with un-obvious causes and test data seems to be hard to get.
To say the least andre.
However it is frustrating for people learning to have their beliefs destroyed by facts.
On the contrary. i don't mind that so much. But what IS frustrating is to BUILD a belief system on what people present as fact, only to find the "facts" turn out to be something entirely different in the firstplace Let me put it this way.
How many THOUSANDS of threads, here, at Studiotits, and other forums(even this thread), have posts from experts(Brian Dayton, Rod Gervais, Eric Desart, yourself and multitude of others) offering test data "proof" that TWO LEAF systems are superior to mutileaf systems. Not to mention pictures showing what a TWO LEAF system is.
Now, correct me if I'm wrong, but from everything I've read, a TWO LEAF system is defined as TWO distinct quantities of MASS, seperated by an airgap. Whether or not a stud creates the airgap is irrelevent. I've also been led to believe, this is called a MAM system, and or a DOUBLE LEAF system as well, no?
So, if that is indeed TRUE, what does one do under those circumstances other than come to a conclusion these are so called "facts", and speak for themself. Now I find this MASSIVE piece of hidden information, and after ALL THESE YEARS, I am not just frustrated....frankly I don't have words for it.
The other thing that makes me frustrated is CONTRADICTION in not only the FIELD of Acoustics, but with some people statements that APPEAR to contridict themself.
Here is what I mean,
As a starter fig 5 on pdf page 8 shows several multiple leaf walls. The best isolation at 63 Hz is 32 dB achieved with a double leaf construction.
I must appologize at this point. I did NOT see that link the first time I read your post. However, now that I HAVE read the entire linked document, something is not jiving here.
First you say
fig 5, Page 8 shows "several MULTIPLE LEAF WALLS"....
But when I look at both fig's 5 & 6 on that page, the author labels these as DOUBLE LEAF!!!! From everything I've read, including this thread, I've been led to believe these are exactly what you call them...multileaf..not double leaf.
Then you say....
The best isolation at 63 Hz is 32 dB achieved with a DOUBLE LEAF construction.
So I looked at the link again and immedietly got FURTHER confused.
This is why. APPARENTLY, I do not understand the term LEAF, as the BBC author implys a LEAF can be a MAM assembly, which in this case is a STUD partition wall, sheithed on BOTH faces with a layer of mass. He calls this a SINGLE LEAF, which contridicts everything I've read over 10 years. Right from the beginning, on (PDF)Page 5, the BBC author says this:
Fig. 2 shows the sound insulation of a
staggered stud partition compared with those of other
single leaf partitions.
Even, the heading below the figure states these are SINGLE LEAF assemblys
Apparently, I'm not the ONLY one who is confused.
Here is why. The author calls a standard partition wall(TWO MASS's seperated by a stud which creates an airgap), a SINGLE LEAF. From everthing I've been led to believe, this would be called a DOUBLE LEAF, no?
Even you call the figure at the top of fig 7, ..a DOUBLE LEAF, which is the one with measured isolation of 32db at 63 Hz.
But then the author calls the two assemblys below it DOUBLE LEAF as well!!!
Now, even this thread has defined a TWO leaf system, as well as a THREE LEAF and FOUR LEAF system, no?
This is why I labeld the pictures on my first post....a SIX LEAF system. But apparently, this is NOT the case, as here, the BBS author calls ALL the examples in fig. 10(page ) TRIPLE LEAF!!! Even the one at the top that is a typical MAM assembly(2 distinct MASS layers seperated by an airgap).
Again, in Figure 11, the author calls these different types of assemblys,....TRIPLE LEAF. Which now gets really confusing as I see FOUR distinct MASSES, seperated by THREE AIRGAPS,
Yet in other figures(5 & 6 for example) they show the EXACT same thing(4 distinct Mass layers and 3 airgaps, but now the author calls these DOUBLE LEAF!!!
And THEN, he calls this a DOUBLE LEAF, which from everything I've been led to believe, is a TRIPLE LEAF!!
What the heck is going on here????? I don't understand how an airgap created by a stud is any different than an airgap with NO stud...as in Figure 5c, 6c, 8c.
To be absolutely clear, the author states this.
On PDF Page (9)
The results are shown in Fig. 8(a)
(overleaf). The first leaf was made from conventional
70 mm studs fitted with a layer of 15 mm plasterboard
and a layer of 9.5 mm plasterboard each side.
FRUSTRATION?????? What a massive understatement andre. I rest my case.
So, WTF is going on here????
On a lighter note, in another section, the author states
the first layer is 19mm "gypsum board but the next layer is 12.5mm plasterboard
???? I thought "plasterboard" was just another name for drywall, which is made from "gypsum". Apparently not. What is Plasterboard made from? Here is the
Legend. btw, I'v never seen those metal stud types with another "H" shaped flange. How does one get the drywall into the flange? It would appear they would have to assemble the studs around the drywall first, and then fasten the whole assembly in place. GAK!
Keep on learning and don't worry about the headaches trying to learn the acoustics.
Headaches? I get no headaches andre. However, this reminds me of someone on another forum who replied to one of my threads, and implied I take "meds", which implied there is something "wrong" with me. From what I see now, I'd submit I am correct when I told him....it appears the shoe is on the other foot. Afterall, one of his posts was the first time I read an explanation of a TWO LEAF SYSTEM.
I believe the shoe fits him perfectly now.