Studio layout, design and construction

[Soundman2020]

It's not that a multiple-leaf is BAD perse, but it's WORSE against a 2-leaf.

But the way I understand it, once you get down to the "mass law" part of the curve, it's roughly the same as a ONE-leaf wall.

Or am I misunderstanding that graph and the paper that it comes from?


- Stuart -

[Ro]

Yes, just like a 2-leaf.
When dealing with ultralow frq (say<80Hz) you'll have a problem anyhow. You'll need A LOT of mass to isolate below those frequencies.

[Soundman2020]

Thank, Ro, that's what I figured. I'm still on the learning curve, but you and the others have helped more than you know! If you are ever in Chile, I owe you a couple of beers!

So, if I understand it right, the big advantage of 2-leaf vs- 3-leaf is that with 3 leaves you hit the mass law part of the curve at a much higher frequency, whereas with 2-leaf you don't hit mass law until you are getting very close to the bottom end of the spectrum. And Green Glue just happens to be very effective at around the same place where 2-leaf hits mass-law, thus extending your range even lower.

Did I get it right now?


- Stuart -

[mika]

I guess I must have learned a hell of a lot from you guys already

an now you can impart your knowlege to the next generation.... like me

remember my last question please

And there is another question.
Every finished window i can get here is alreday a 2 or 3 leaf system. when i have now 2 windows between the rooms, i have the same problem like with the walls!?

Depending on this law of acoustics ( simple mass and the theairspace law), it's better for me to get 2 pices of 10mm single glas for the window between live and controlroom!?

cheers
Mika

[Soundman2020]

Hi Mika,

Yes, the same rule applies to glass as well. The general recommendation is NOT to use standard double-pane glass (called "thermopanel" where I live), but to build your own window, with two panes of very thick laminate glass, but of slightly different thicknesses.

If you look at other build threads here I'm sure you'll find lots of examples of how to do your window right. I seem to recall that Rod gave a great explanation of exactly how to do it, in a thread somewhere, but basically you need two (only two) panes of thick laminate glass (not plate glass), separated by an air gap. Some people recommend that you angle your glass at 6 degrees (or more), but other people say to not do that. The jury seems to still be out on that point! Personally, I reckon that it is useful to reduce reflections on the glass (light), and if you have the skills necessary to do it, then I would. But others will disagree, I'm sure!

By the way, the same applies to doors, too. You need two doors, one in the outer leaf, one in the inner leaf, and they both need to be solid and massive, and must seal absolutely airtight when closed. The doors must be solid core, not hollow core, and you might need to beef up the mass somehow. Some people even put lead plates inside their doors, for extra mass...


Regarding your airlock question: I don't want to try answering that myself, since I'm not sure of the acoustic implications. I'd prefer that one of the real experts (not the "pretend" expert, like me), such as maybe Ro or André, answer that one for you. I think I see the issue, but I'd really like to hear their opinion.



- Stuart -

[AVare]

Some people recommend that you angle your glass at 6 degrees (or more), but other people say to not do that. The jury seems to still be out on that point!

There is no question. there is no acoustic advantage to angling the glass. Aesthetics, potential light glare if not aimed properly, yes.

I do not understand the door question.

Andre

[mika]

my question was why it is nessesary that the area between the live and controlroom (marked with number 2) has to be airtight to the small foyer area (number1)

is there any important hurt in soundisolation?

cheers
mika

[AVare]

my question was why it is nessesary that the area between the live and controlroom (marked with number 2) has to be airtight to the small foyer area (number1)

is there any important hurt in soundisolation?

If you are using it only as a foyer, no. I would strongly suggest making that a sealed double door so that you can use that as a isolation booth on occasion.

Andre

[mika]

Thanks andre this help alot.

Now my plan is to have area number 4 as the airarea between the 2 leaf-system.
I will go the way soundman explaind me ,and rebuild one leaf of the given walls, to get a 2 leaf system with my new inner studiowalls, from every room to another.
so i have 2 seald doors and leafs from live to controlroom, i have 2 doors and leafs from controllroom to area number 5 (big foyer) and a 2 leaf-system to the other rooms number 1 and number 6.



Is this the way to go for my projekt?


cheers
mika

[Soundman2020]

It looks good to me Mika, but I think xSpace did have some reservations about putting your entry hall in your "air" space. Maybe he could explain why he was concerned about that, and if it is going to be a big issue or not.

Also, please don't trust just my opinion! I'm not an expert on this, so I'm hoping some of the real experts can chime on and comment on your final design, before you start building it.


- Stuart -

[mika]

Hey friend's
It's me again

Yesterday i'd make some soundisolation tests in the room.
I found out, that the wall to room number 6 vibrates with the bass very hard, so i start a simple test.
I put the speaker in a selad, very thick woodbox, and after this the basnoise in the room number 6 was much quiter, nearly silence.
How can it be?
When i understand the 3 leaf disadvantage right, the bas has to be more loud!?

Is the 3 leaf system law only working, when the airgap between the 2 leaf wall, and the single leaf wall is sealed?
When it's like i think, i have a benefit of the existing 2 leafwall because the space marked with number 4 won't be selaed, to the fesh air from outside. There is no need of silence outside the bulding, only a litlebit more silence in the room next to the studio.

Space number 4 will go around all my new builded walls, and the small foyer.

I am confused about the results of the test

Can somebody explain me why it's like it is?

cheers
mika

[Soundman2020]

because the space marked with number 4 won't be selaed,

It has to be sealed! It is your air gap, your "spring". If you don't seal that, and it is open to the outside, then in effect you only have one leaf.

How can it be?
When i understand the 3 leaf disadvantage right, the bas has to be more loud!?

How did you test this? Did you play full spectrum pink noise or a slow sweep through the speaker, or was it just music? Did you measure the results with a good quality sound level meter? What speaker did you use? Is that speaker even able to produce the very low frequencies where the problems are going to be? In general, only a large sub-woofer can get down that low, so if you didn't use one, then I'm not surprised. The frequencies where the third leaf comes into play are way down at the bottom end of the spectrum, in the area where kick drums, toms, bass guitars and the bottom end of keyboards live. Your average hi-fi speaker cannot get down to those frequencies, and neither can cheap studio monitors. You'd need a really good full-range studio monitor, or a sub-woofer to properly test that. Do you have the make and model of the speaker?

And in order to get an accurate picture, you'd also need to measure the levels with a sound level meter.

Also, you might find that you just happened to hit the resonant frequency of wall #6 with the speaker outside the box, and that the box just happens to be good at blocking that frequency! Or perhaps you started out with the speaker located at a node that excited the wall, but then you placed it in a null for that frequency when it was in the box...

There are many, many reasons why your basic test didn't give you the results you expected.

But if it concerns you, then you need to do the test again very accurately, with a speaker that really can produce the frequencies that are likely to be a problem (20Hz - around 150 Hz), sweeping up through the entire low end of the spectrum and measuring carefully with a sound level meter. Then repeat the tests for several different locations of the speaker.

[mika]

Hey Stuard.
Thanks again for reply.
I want to go back to the 3 leaf system.
In the attached pic i marked a seld leaf with red color a seald airspace with blue, and a, to the outside of the building, not compleatly seald area with green.
All the Green will become one room.

This was also the way i tested the soundisolation.

try to imagine room number 3 was just a little seald box, where i placed my speaker inside.

So i had 3 leafs to room number 6 right?
One leaf to area 4 and another 2 leafs to area 6.
Is this a 3 leaf system because of the not seald airspace?

I did the test with my Yamaha MSP10 monitor which will become my mostly used Speaker. I'd power it up short before clipping.
I'd play music and also pink noise, both with the same result.
The speaker stayed in one position, i just put a woodbox over it.

So this is the situation now, and i won't belive that my plan is a real 3 leaf system.

When this is a 3 leaf system, then i have a 5 leaf system to the room next to number 6 (not shown at picture) an there was no noise , nothing to hear, no bass, no mids, no highs.

These physics drive me crazy
cheers
mika

[Soundman2020]

OK, so if your green area is not sealed, and is open to the rest of the world (or to the inner room), then you don't have a three-leaf system! You have something like a one leaf system plus a two leaf system, it seems. I have no idea how that works, acoustically, but my guess would be that it doesn't work very well. especially the one-leaf part that is open to the outside world!

This might be the source of your confusion.

Question: Why is the green area not sealed? WHERE is it not sealed? Perhaps you could show on the diagram the places where it is open to the outside.

In any event, to get a proper two-leaf system you'd have to seal that space and also remove the inner layer of drywall from the outside walls, and also seal up those walls.

So, from your comments, it sounds like you already built the walls? If so, that was pretty quick! How about some photos?

These physics drive me crazy

That's for sure! Me too!


- Stuart -

[AVare]

It is a three leaf system whether the space is sealed or not.

Andre