recording studio in germany - need some advice

[themHorses]

thanks again for the answer and lets stop the german for now

To keep it simple, you do not need to do an inside-out wall. You should build a normal wall with insulation behind it. After construction is complete, you can treat the walls inside the rooms for acoustic purposes.

ok i think with your (keith) and steves answer i can combine the right way.
the confusion arose about that sentence from steve where he was pointing out that we wold need "additional" lumber for a normal wall.

what i understand now is that we would build the inner leaf like this (from the outside to the inside):

- wooden frame filled with insulation)
- three layers gypsum
- wooden frame to treat the wall acoustically

so the second frame is not for soundproofing but for acoustical treatment because we have the blank gypsum now pointing TO our room
am i right, am i wrong, am i right, am i wrong?

one more question. i read a lot of threads to find what sizes your studs are
and found a lot of different suggestions including the wrintings of john at sae, where he is talking about 75x35mm studs. i know it depends on our total weight. but if we`d use three layers of 15mm gypsum and a ceiling that is rested on that inner frame i think that size would do well.

am i right, am i wrong, am i right, am i wrong?

as always: appreciating your answers

btw: that truck looks nice in front of your house, keith
i wish we would have settled everything with our potential landlord already

greetings from berlin in germany
jens[/quote]

[sharward]

what i understand now is that we would build the inner leaf like this (from the outside to the inside):

- wooden frame filled with insulation)
- three layers gypsum
- wooden frame to treat the wall acoustically

so the second frame is not for soundproofing but for acoustical treatment because we have the blank gypsum now pointing TO our room
am i right, am i wrong, am i right, am i wrong?

Correct. However, I would like to clarify something. In English we refer to "framing" as the lumber used to build walls, floors, ceilings, etc. -- like this. We also use the word "framing" to describe what goes around a picture that hangs on a wall -- like this. We sometimes describe the process of building acoustic treatments/traps added to walls, visible inside the room, as "building frames and putting insulation in them," just like what was done on this page, and then hanging it on a wall just like a picture or a piece of artwork.

If auf Deutsch there are different words to describe these different things, then no wonder you're confused!

So, yes, you will use lumber to frame a wall structure ("framing the wall") and put multiple layers of gypsum on it, and then probably frame acoustic treatments and attach them to the finished wall.

I want to make sure that you understand we are not talking about building "two wall frames."

one more question. i read a lot of threads to find what sizes your studs are
and found a lot of different suggestions including the wrintings of john at sae, where he is talking about 75x35mm studs. i know it depends on our total weight. but if we`d use three layers of 15mm gypsum and a ceiling that is rested on that inner frame i think that size would do well.

I think 75mm may be too small for 3 layers of gypsum. I think 135mm would be better. (I'm going to use 5 1/2" (139.7mm) on my project.) Let's see if other experts here agree on that.

btw: that truck looks nice in front of your house, keith

It was pretty exciting to have my first material delivery! There will be much more, I'm sure! I expect there may be pictures of a dump truck (to haul away lots of concrete) and a concrete mixing truck in the hopefully not too distant future!

--Keith

[themHorses]

I would like to clarify something. In English we refer to "framing" as the lumber used to build walls, floors, ceilings, etc. --
If auf Deutsch there are different words to describe these different things, then no wonder you're confused!

thanks for claryfying that, keith.....but i think its the same in german ("rahmen")...

So, yes, you will use lumber to frame a wall structure ("framing the wall") and put multiple layers of gypsum on it, and then probably frame acoustic treatments and attach them to the finished wall.

ok, i got that now......so because our biggest concern is soundproofing, we will focus rihght now on that concept

I think 75mm studs may be too small for 3 layers of gypsum. I think 135mm would be better. (I'm going to use 5 1/2" (139.7mm) on my project.) Let's see if other experts here agree on that.

woohaaa.....that is very big. so you are using these studs just on the corners or is every stud that size?
what do the other experts out there say?

btw. i just received "building a recording studio" from jeff cooper from usa, because i couldn`t get it here. reading this makes my brain go . very enlightning that book
it answered some of the smaller questions i had. but i still have some more. but i will make a sketch before i post them

greetings to all of you
btw did i say that i got 2 weeks off now

[sharward]

I think 75mm studs may be too small for 3 layers of gypsum. I think 135mm would be better. (I'm going to use 5 1/2" (139.7mm) on my project.) Let's see if other experts here agree on that.

woohaaa.....that is very big. so you are using these studs just on the corners or is every stud that size?

Every stud.

Here in the US, most framing is done with "two by fours" which are 1 1/2" x 3 1/2". The next size up from that are "two by sixes" which are 1 1/2" x 5 1/2". I did a little Googling and I discovered that 135mm deep studs are a standard size and is close to the 5 1/2" studs I'll be using. However, others may have a different opinion on this. I've been wrong before -- so much so that I'm getting really good at it!

Perhaps the lumber in your part of the world is stronger than ours, or much more expensive, or for some reason 135mm studs would not make sense.

btw did i say that i got 2 weeks off now

Excellent! You'll have your studio all finished in that time, right?

--Keith

[knightfly]

Three layers of plasterboard can be supported by a 2x4 WALL frame, but usually NOT for ceiling (unless it's a VERY small room) - however, these would need to be placed on closer centers - 400mm centers instead of 600mm centers - this will actually HURT isolation of the wall by a couple of dB.

Better to use 2x6 wall framing (all of it is same size) and space the studs on 24" (600mm) spacing - this lets the wall "flop" just a bit more, which improves isolation a little.

BTW, our lumber sizes aren't "real" - years ago, a 2x4 was really 2" x 4", and came from the saw mill rough surfaced, right out of the saw. Then they started smoothing the wood (planing it) which made the actual dimensions smaller - this eventually evolved to further reduction in size (but not cost ) to the present day, where a "2x4" is really 1.5" x 3.5", a "2x6" is really 1.5" x 5.5", etc - this is probably a major source of confusion when people in Europe try to match inches to millimeters.

In either case, if you intend to support a ceiling frame on your inner walls you need to double the top plates - see the diagram below for a visual... Steve