MoRossi Studio Contstruction Proceedings

[nuH]

First Things first!

Hello Folks, my name Peter and since the beginning of this year, I have the opportunity to help out with the construction of my friends' (Rossi) studio in Frankfurt, Germany. I found Johns' Forum, propably like most of you by googling for information on studio construction.

I did read some books on the topic (balou, newell) including some more advanced books. (which I admit I didn't understand much of <.<)
But the thing with books is, they don't answer questions!

So here I am.

Since building this particular studio will be a longer process, due to both of us working on it in part-time fashion, making my questions part of a diary will hopefully provide enough context to keep you guys interested!


Without further ado:
_________________________________________________________________________________

I best start with some basic information on the location and the purpose of the studio:
---
- the studio is located adjacent to a tire storage of an autogarage in an industrial area.
- within the approach-zone? of FFM Airport (big)
- will only be used in the evening/late-night/weekends
- mostly for rock/pop/metal productions and whatever else we can get
- extremly low budget (5k-10k€)

Next, I'll list some of the already existing equipment:
---
Tascam DM-4800 Digital Mixer
MOTU 828 mk2&mk3
2x Maudio EX66 Monitors
PC Intel Quadcore running Cubase 4
+ diverse outboard eqp and mics

Next, some pics to give you guys an idea what we are dealing with:
---

rawviewtop.jpg

Ceiling height in the recording room (up to the beams) is 4,20 meters; Ctrl.Room Floor level is at 2,20 meters (leaves 2m to the beams >.<)

Problem 1: The concrete slab between 1st and second floor is only 20 cm thick and vibrates noticably when playing music loud!

We are planning to extend the Ctrl room from the open side all teh way towards the wall. we have 3 H Profile Steel bars that should be sturdy enough to carry a floor. towards the backwall we want to seperate a small vocal booth.
(Will provide drawing asap)

Take a look from the open side into the room:

ctrl.jpg

Problem 2:

I want to do a reverse room in room but i also want to use the space between the roofframing to hang absorbers. Since the beams extend all the way from one room into the other and a bit towards the outside, this is essentially a breach of my seal no?

There must be no tearing down of any walls sadly.

rawview.jpg

doors.jpg

This is how the place looks like if you'd strip it down. It has been used as testing room for Showlights, so it has mostly just been painted all black. The ceiling framing is still covered with a single layer of gypsum board, but we will remove that eventually.

Problem 3: As can see from this simple drawing is that the wall to the adjacent tire storage doesn't go all the way up. The walls are also sloppily built and the mortar has cracks and holes.

cracks.jpg

Windows (new double-glass) and doors actually exist, but will have to be modified. The door opening to the right is going to be walled shut.


_______________________________________________________________
Hmm, enough for today, I shall edit my post tomorrow and add more details


Thank you for taking time to browse through my messy thread. Please suggest what additional information you peeps might want, I shall add it!

Regards, Peter

[xSpace]

"The concrete slab between 1st and second floor is only 20 cm thick and vibrates noticably when playing music loud!"

With some where in the neighborhood of a 14 foot height for a ceiling, two things come to mind.

One is that you will be hard pressed, that means it ain't gonna happen, that sound will "noticeably" vibrate an almost 8 inch thick concrete slab.

Second is that who can see that far away? And not be afraid that the building is going to collapse?

Say what you want to believe, but it will not pass as fact here.

[nuH]

Hi xSpace,

thank you for taking the time to reply.

Just to clarify, are you saying, no way that slab is 20cm, or are you saying no way a 20 cm slab can vibrate? The thickness might be wrong, I'll remeasure it! But i do clearly "feel" the kickdrum moving it as I turn it up.

Another thing i might have to clarify, The building itself essentially doen't have any floors, just ground level with a light metal roof 4,20 from the floor. So there is no additional floor structure it has to carry. When i said 2ond floor i was refering to the small "sub-floor" which is labled Ctrl.Room!

Sorry if my English is inaccurate, I'll try to improve!

Regards, Peter

[Soundman2020]

Hi Peter, and welcome!

I agree with Brien: It doesn't make any sense to put a control room on the second floor. Why do you want to do that? It would be much better to move something else up there, such as offices, storage, machine room, lounge, bathrooms, or whatever, and keep the control room on the GROUND floor, where it can be isolated properly.

Second floor construction is a big problem, for the exact reason you already discovered. Even a thick concrete slab can act as a resonant membrane when it is not damped, and especially when it is over a large air cavity. There are ways to deal with that, but most certainly not on your budget! So I'd really suggest that you do the sensible thing, and abandon the idea of building any isolated room on the second floor. Put all your rooms that need isolating on the ground floor.

within the approach-zone? of FFM Airport (big)

Ouch! Then you have an even bigger problem, and even more reasons to NOT build anything on the second floor. Before you do anything else, get a sound level meter and find out just how loud it is when planes are landing. You need that information in order to design the isolation system for your studio. If you can, get a spectrum analyzer as well, to see the relative sound levels at different frequencies: I suspect that there will be a lot of low-frequency noise, which is the most difficult to deal with.

Ctrl.Room Floor level is at 2,20 meters (leaves 2m to the beams)

That's another reason to NOT build the control room up there! You don't have enough room height. A low ceiling in a control room is a bad idea.

we have 3 H Profile Steel bars that should be sturdy enough to carry a floor.

I always get scared when I see people taking about major structural issues, and saying "I think" or "we hope" or "it should be enough"!!!! Big mistake. You need a structural engineer to make that call. Happily pay the few hundred dollars that he'll cost you, and get him to come examine the building, look at your plans, and tell you what you can and cannot do safely. Just so you know, concrete weighs about 2,300 kg per cubic meter, roughly (depending on type): It would be really sad to have a nice studio built, then have a few thousand kilograms of concrete come down on your head, because what you "thought" was going to be "good enough" actually wasn't...

I want to do a reverse room in room

Do you mean "inside out"? If not, then what do you mean by "reverse"?

Since the beams extend all the way from one room into the other and a bit towards the outside, this is essentially a breach of my seal no?

Yes. It's also a major flanking path. Yet another reason to not build the control room up there. I can give you more reasons, too: engineers will hate the idea of having to run up and down the stairs all the time, when trying to position mics, instruments and people...

The walls are also sloppily built and the mortar has cracks and holes.

That can be fixed: plaster the entire wall. In other words, cover it with a layer of stucco (mortar). If done properly, that will seal all those cracks and holes, and give you a much better outer leaf. Then seal the plaster surface when you are done.

just ground level with a light metal roof 4,20 from the floor.

A light-weight metal roof? And you are on the approach path to a major international airport? That roof is going to need some type of damping, at least, and then you are going to have to figure out how to get good isolation. I'm thinking that this will be one of those cases where three-leaf construction is unavoidable.

So there is no additional floor structure it has to carry.

Ummmm.... yes there is, if you want good isolation! And being on the approach path to an airport means that you DEFINITELY want good isolation! That rood won't have to carry a floor structure, but it will have to carry more mass. Once again, you need the structural engineer to take a look at it, and tell you how much more mass it can carry.

- Stuart -

[nuH]

Hello soundman2020, thanks for the kind welcome,

indeed you confirm my worst fears;

But we are pretty much commited to this location! Is it generally possible, with a proper revised layout and proper construction to build something usable here? ( After a quick call with my colleague we decided not to build the ctrl. room up there )

> We're still a couple of miles away from the airport, but planes are already in decent when they fly over. I want to measure as soon as the place is lockable. The area is not exactly safe ... and too many ppl still have access to it. Will a period over 24hrs, averaged every hour + a maximum plot A-weighted suffice? Or should we try to measure over the course of a whole week? (REW or SMAART; Behringer ECM8000; MOTU828)

>A friend of ours is a pensioned Construction engineer, he told us how to put up the steel profiles. We are hoping to enlarge the usable floor area that way. I'll provide a revised layout sometime this week.

>The roof is insulated with a single layer of glass-wool, about 20cm thick, then covered with something like cardboard to hold it in place.

>I indeed meant inside out. I've been inspired by newells no-room, i think he called it.

Anyways, you guys have been a big help to us already!

Many Thanks,

Peter

[Soundman2020]

After a quick call with my colleague we decided not to build the ctrl. room up there

Great! Smart decision.... What are you going to put up there instead? I'd suggest storage or a quiet office without much people-traffic, so that there's no impact noise on that floor, which might get transmitted down to whatever you'll be building underneath.

So where is the control room going to be now?

Is it generally possible, with a proper revised layout and proper construction to build something usable here?

Probably you'll be able to build something decent, but a lot depends on how bad the sound issue is with approaching planes, and anything else noisy in the area. If you are close to an airport, then I'm guessing that there are plenty of busy roads nearby, as well as noisy industries...

(REW or SMAART; Behringer ECM8000; MOTU828)

No use for SPL readings, unless you also have the means to calibrate them! An ordinary sound level meter will be fine to get basic noise readings ("A" weighting, slow response). The REW / ECM800 / Motu setup will be good for judging relative noise levels for different frequencies, but not for getting accurate overall noise level.

There are methods for achieving high levels of isolation, but they might be out of your budget range. Anyway, lets see how bad the problem is, once you get those readings.

- Stuart -

[xSpace]

>I indeed meant inside out. I've been inspired by newells no-room, i think he called it.

Non-Environment control room.

[nuH]

Hello again;

Non-environment, thats what it was!

I've come up with a preliminary layout, and it looks like this:

RossiStudioLayoutRound.jpg

Some questions that occured to me when I made it where:

> Does this controlroom count as square? And would sitting more or less in the middle be a huge problem? The idea of sitting 38% away from the front wall, floor is because of the better distribution of room modes, right?

> I plan to place hangers from the ceiling all the way to the floor next to the backwall, to get decent amount of absorption.

> The monitor-enclosures aren't really big atm, and we're trying to get a really decent pair sometime soon - so it shouldn't be made too small.

> I'll need to find a suitable staircase small enough to fit into the lobby to provide access to the "old" ctrl.room above the tech.room ...

--------------------------------------------

Do you guys think it could work like this?


Many thanks in advance


Regards, Peter

[Soundman2020]

Does this controlroom count as square?

No, but I think it probably classifies as "round", which is arguably even worse than "square"!

And would sitting more or less in the middle be a huge problem?

Very likely, yes. The focal point of a concave surface is at half the radius, so it seems to me that you are placing your head at the focal point of your curved front wall! I doubt you'd be able to get any usable stereo image or sound stage in such a setup.

The idea of sitting 38% away from the front wall, floor is because of the better distribution of room modes, right?

That's the theoretical point with the lowest concentration of modal issues, along the longitudinal axis of the room.

> I plan to place hangers from the ceiling all the way to the floor next to the backwall, to get decent amount of absorption.

While hangers on the back wall is a good idea, I'm not sure what you mean be "decent amount of absorption". The absorption needs to be spread around the room, not concentrated at a single location. You will need heavy absorption on all your first reflection points, probably more so than with a more conventional layout, due to the focusing effect of that front wall, plus the large reflective side walls that are at all of your first reflection points in your current design.

> The monitor-enclosures aren't really big atm, and we're trying to get a really decent pair sometime soon - so it shouldn't be made too small.

To me, it looks like you are trying to do flush mounting, also known as soffit mounting, so your "speaker enclosures" should be the entire wall! You don't go out and buy speaker enclosures for flush mounting. Rather, you just build a solid, massive, thick, heavy, dense, rigid wall, and put the speakers in them. That wall also is NOT the inner-leaf of your MSM system, which is what you are showing right now. If you built it like that, the isolation of your control room is effectively reduced to just plain old mass law, so I guess you must be planning on some pretty major mass for your walls! 1/2" Lead plate, maybe?

Do you guys think it could work like this?

Frankly, I see some rather major problems with it, that would take a lot of work to mitigate. Your current design shows that you are looking into a corner, where two glass panes meet. I'm not sure how that would work out, either acoustically or visually: having a joint in the glass right in the middle of your main view into the LR doesn't seem like something I'd want, and acoustically it would be akin to a gabled ceiling, with all kinds of strange reflections going on in there. Comb filtering and phasing issues come to mind... While you might be able to make your current design work, I certainly wouldn't want to be the one trying to figure out the acoustic implications of curved walls with the mix position at the focal point, and a "gabled" glass front wall! To be honest, I'd modify that design to be a more conventional corner control room, with correct geometry, and also fix your soffit mount design.


- Stuart -

[nuH]

Hi Stuart,

thanks for your fast reply

> I agree on the window! It didn't think all that much about the joint when i made it!! We managed to get some 1x1.8m double laminated double glass windows & Doors from a jewelers shop -- they are kind of sturdy. So i wanted to make use of them - but I could just use one, horizontally mounted instead - much simpler ...

> Does the focussing effect work like that with sound originating from the wall (i. e the speakers)(I'm thinking of the "whisper gallery"). Or just with reflections or sound originating from within the room. I like the basic layout like this because we can have good eyecontact with the musicians. Don't most ctrl.rooms with with splayed walls approach a halfcircle shape, someway? Just with sharper angles.

> I was planning to to make all walls inside out - besides the baffle around the speakers. Hangers would cover the whole surface of the 2 walls which meet in the back corner. I just made a quick layout - after I settle on one ill work on the actual implementation of the wall construction into the model.

>Naturally we intend to buy decent monitors, not the enclosures .

>I'm not too sure about the flush mounting procedure:
- I didn't put enough detail into the drawing concerning this issue.
- what I essentially wanted to do, was shaping the inner leaf into a cavity, with sufficient support from the floor so it doesn't move with the speaker. Place the monitor inside - fill with leftover rockwool - and mount a baffle.

(edit: http://www.johnlsayers.com/phpBB2/viewt ... 8&start=30
Ah I see so I should build the support between the leaves so it is decoupled from the front wall!
)

-There would still be air between the ctrl room wall and the rec room wall, no contact whatsoever. No bricks, concrete or lead!

> I thought about the modes issue, and in a generic rectangular room, you have of course a modal distribution on 3 axes to consider, with the z axis usually limited in some fashion. Maybe we can avoid the worst (coincidence) by making sure theres enough space upwards? There is no way i can get out of the middle of the x-y plane without making the room significantly larger, is there? Or make it rectangular and align it parallel to a wall.

Also, could you link me to an image that conveyes what you mean by conventional corner ctrl. room? I'd be much obliged

Once i settle on a basic layout i can start with the planning of the framing ))


In any case! Thank you guys again big time for helping us out!


Regards Peter

[Soundman2020]

We managed to get some 1x1.8m double laminated double glass windows & Doors

Sounds interesting, but tell us more: When you say they are both "double laminated" and "double glass", to me that sounds like there are two pieces of laminated glass in a single frame, with an air gap between them. Is that what you have? Also, how thick is that glass?

Does the focussing effect work like that with sound originating from the wall

Think of it this way: If you were to go and stand right next to that front wall with music playing from the speakers, would you be able to hear the music, or would you just here total silence? Obviously, you'd hear music. so if you can hear it, then so can the wall. Meaning that sound waves are arriving at the surface of the wall, and therefor will follow the normal laws of physics regarding reflection, angle of incidence, angle of reflection, etc.

Don't most ctrl.rooms with with splayed walls approach a halfcircle shape, someway? Just with sharper angles.

Yup! But that's the key: "Sharper angles". Not circles. The angles are there for a reason, and are carefully calculated. They reflect sound AWAY from the listening position, not TOWARDS it!

I was planning to to make all walls inside out - besides the baffle around the speakers. Hangers would cover the whole surface of the 2 walls which meet in the back corner.

Well, yes and no! I like inside out walls, and you can put a lot of insulation in them, but you don't want to kill the room! Hangers along the entire length of both rear-side walls would probably do that. The idea if hangers (and bass trapping in general) is depth, not coverage. They need to be deep, but not to cover the entire wall surface. That sounds like too much absorption, to me. They key to placing absorption is to put it in the right place, and make it the right thickness. You need enough to do the job, but not so much that you leave the room stone cold dead. Yes, you need lots of it to treat the bass, and help damp the modes, but that automatically takes out all the high end too, so you perhaps need to cover some of it with the right reflective surface, in the right places.

what I essentially wanted to do, was shaping the inner leaf into a cavity, with sufficient support from the floor so it doesn't move with the speaker. Place the monitor inside - fill with leftover rockwool - and mount a baffle.

Once again, that sounds like you are planning to leave the speaker inside the MSM wall cavity. That's not the idea. If you did that, half of the bass power would be radiated INSIDE your MSM wall. Not a good idea! The speaker soffit needs to have an entirely separate cavity, that is NOT part of the MSM system, and is totally sealed off from it.

Ah I see so I should build the support between the leaves so it is decoupled from the front wall!

Nope! NOTHING goes between the leaves of an MSM wall. Both leaves are totally sealed airtight, with nothing between them but air and insulation. Each leaf is a single, solid, massive surface with no holes in it. You cannot put your speakers half between the leaves.

-There would still be air between the ctrl room wall and the rec room wall, no contact whatsoever. No bricks, concrete or lead!

But if you put your speaker inside the cavity, then half of the power is radiating into the cavity, so you no longer have a two-leaf MSM wall with respect to the speaker: rather, you have two single-leaf walls that are no governed by mass law equations, not by MSM equations.... And mass law equations are not very exciting...

I thought about the modes issue, and in a generic rectangular room, you have of course a modal distribution on 3 axes to consider, with the z axis usually limited in some fashion.

There's no limit on the Z axis: Modes work identically in all three dimensions. sound waves don't know "up" from "front", nor "down" from "left". They just travel in all directions, and interact with the room boundaries, the exact same way for all boundaries. In your room plan, you have far more complex modal activity, with no simple way of predicting the modal behavior. The Z axis remains predictable, but only for axial modes, not for tangentials or obliques. And the modes related to the other walls will ALL be tangentials and obliques, no axials at all. The only way to predict the modal response of such a room is with FEM/FEA software, and and really good operator who knows how to set up the boundary conditions, and how to interpret the results.

So basically the modal behavior of your room is unpredictable, for all intents and purposes.

Maybe we can avoid the worst (coincidence) by making sure theres enough space upwards?

Modes don't care about directions. A mode is just a path around the room that happens to exactly fit a certain wavelength, or a harmonic of a wavelength. As long as that path exists, any reasonably loud tone (or harmonic) that matches that wavelength will follow that path, pouring energy into it, setting up a standing wave, and thus forming the mode. The up/down/left/right/front/back of the room have no bearing on the mode: If you flipped the entire room onto one end, the modes will still be identical. Modes don't care about direction, since sound waves travel equally in all directions. Directions are just conventions that make sense to people, but sound waves don't care. If there is a path that reflects them around and back to their starting point, and they turn out to be in phase with themselves on arrive there, then you have a mode. The directions involved, and the walls involved, are immaterial: The mode exists simply because there is a path around the room for that wavelength.

There is no way i can get out of the middle of the x-y plane without making the room significantly larger, is there?

You could change the speaker angle...

Or make it rectangular and align it parallel to a wall.

Rectangular rooms are another option, but harder to do an RFZ design in.

Also, could you link me to an image that conveyes what you mean by conventional corner ctrl. room? I'd be much obliged

Sure! Here's a couple. There are more on the forum, if you go looking for them...


http://www.johnlsayers.com/phpBB2/viewt ... m+#p120685
http://johnlsayers.com/Pages/Cloud.htm


- Stuart -

[nuH]

Hihi, 'tis a me! - again - took me a while to redo the Layout ...

> Yea, the windows are like this:

In total 35 mm thick, 2 planes laminated together ca. 6mm each <> 1cm airgap <> another 2 panes, 6mm each.
Four windows 1,80x1,00 and two 2,00x1,00 are available to us, + a doublewinged glass door with similar construction.

> I changed the layout to this:

RossiStudioLayout3.jpg

> 1 Cornertrap, the walls will be inside out, exept the soffits.
> each line represents one leaf, not a solid wall, mind. I can always brighten up the sound by adding slats, can't I? I think we will have to tune the recording room later on anyways!
> The sweetspot is a little behind the mix spot, it would be nice if we can fit a client seat in the back.
> I was wondering whether i should place the door/window where the red lines are, cuz with the current layout we have to roll back with the chair to see into the siderooms.
> Or move the speakers closer to the middle, and cover part of the window.

-> What would you guys suggest?

-> Concerning caulk, most of you guys use special application caulk, don't you? Is there a special acoustic property besides sealing whatever kind of gap airtight for a long time, that I am missing?
-> The whole room rest on an industrial grade concrete slab, no basement. Covered with felt and a carpet. Will i get away with just laying laminate, and call it a day - or do i need additional treatment to prevent flanking from one room to the next?

-> Concering the Roof I'm not really sure how to treat that yet, any ideas?

RossiStudioDach.jpg

Anyways, I'll post some real pictures after we are finished cleaning out the entire place


Your help is greatly appreciated, many thanks!

Peter