About myself:
My name is Marco, I'm 30 years old, and I have been working as sound engineer (tracking/mixing) since 9 years. I'm a long time lurker here (at least 3 years), I registered this account a year ago but made the first posts only a month ago.
I'm writing from the south-west Sardinia, an Italian island located between Italy and Spain. It is a pretty big island actually, if you ever got an eye over the Mediterranean Sea map you should have seen it
I'm studying and reading studio design concepts since few years, I've took my time to get into the vast moltitude of counter-intuitive concepts related to sound isolation and general acoustics rules. The journey is still far away from being completed, as my questions below will reveal shortly
I read (multiple times to be honest) these three books:
- Home Recording Studio: Build It Like the Pros by Rod Gervais
- Recording Studio Design by Philipp Newell (... ok I know... )
- Studi di registrazione e di ascolto, sale multimediali e home theater by F. Alton Everest. It's the Italian translation of the book "Handbook of Sound Studio Construction"
I received a warm welcome and high valuable answers already from some forum members, this place is wonderful.
The purpose of this thread:
I'm starting this thread for three main reasons:
- get help on some topics I have not enough expertise of
- make a sort of "design diary"
- stimulate discussion around topics that can be useful to other members in the future, as I learned myself a lot of thing because of threads like this
The goals:
What I would like to achieve is:
- a studio/rehearsal facility with two rooms: a control room, and a live/rehearsal room
- the studio must have sufficient isolation (more details of "sufficient" later) to not disturb neighbours and studio operations during the entire day (9am - 22pm is the desidered time of operation in my actual plans), to be achieved via a room in a room" design
- this is gonna be a commercial project on a tight budget (more details about the budget will follow)
- the control room must aim for a very good (can I say towards flat?) frequency response, short reverb time at the low frequencies, good habitability (I don't know if this word exists, but I think it makes sense
)- the live/rehearsal room should have variable acoustics, with a natural/balanced reverb decay that allows the usage as an "out of the way" recording room and rehearsal space
- a small bathroom
- if possible, control room and live room entrances should be indipendent
- fresh air supply
- temperature and humidity control
- if possible, not too ugly appearance
The budget:
I'd prefer to keep it under €30,000. I know it's not a great sum... I think I can stretch a little above but... we'll see how the design develop.
Where I am now:
I am in the research/planning phase.
I own an "empty" (you'll get the meaning of those double-quotes soon) place of 90 sq. meters (969 sq. feet), at the ground floor of a small 3 floors building, with neighbours above and at one of the four sides. Walls are 3,46 meters (9,84 feets) tall. Full details of this place will follow (I hope I didn't forget anything). There is a window in the actual bathroom, that I think will become a part of the "external leaf" wall (= will be walled, since it brings no natural light and can represent a potential weak spot for the sound isolation system).
There is also a glass-door in the external wall of the small room at the back of the building. Its future is part of the questions at the bottom of the post
The actual bathroom will be demolished (even the walls), and the small room separation wall at the end of the main space will be demolished as well, creating a single space to work with.
These walls will be removed: It will become like this: Loudness and isolation:
As the image above shows, the outer shell of the room misses one wall, the front one.
Instead of the front wall, there is a huge, old window-wall (I don't know the exact word to describe it) made of glass and aluminium with several air leaks: This place was a shop once. The window was a showcase.
In front of that, at about 2 meters (6,5 feets), there is a road with moderate traffic.
The measurements (all values refers to maximum values measured by the spl meter, "slow" response, "C" weighted)
1. Environmental noise in the studio space The maximum value measured was 102dB, due to a heavy truck accelerating in front of the building.
Of course, the farther I measured from the street, the lower the maximum spl (as shown, 82.3 dB);
In the room above the studio space (neighbour 1), the level was about 50dB. Near the window facing the street it raised to 60dB when cars were passing by.
2. Noise with drums and bass playing loud in the room In the studio space, the maximum pressure was measured near the drums, 120 dB at about 1 meter.
Adjacent the right side of the studio space, there is the stairwell and an apartment (neighbour 2), slightly higher than the studio space floor.
I can safely presume that in that apartment the noise will be like or slightly less the noise measured in the stairwell: 101.9 dB In the neighbour 1 apartment, the measured level with drums and bass playing was 93.2 dB.
Interesting fact: the floor was vibrating, I could feel it by the feets.
I also touched the pillars, and they were vibrating too (a little less, but still vibrating).
Since the studio space floor is rigidly connected to the pillars and therefore to the 1st floor, I think I have the classic "flanking path" situation of the impact sound being transmitted via concrete in addition to the airborne transmission.
I don't know if the 1st floor is being put in vibration by airborne sound or by the transmission via the pillars.
Given these measurements, I think that I'll have to achieve at least 60 dB of isolation.
The questions:
1) Due to local regulations, I cannot change the aesthetics of the front entrance of the building. I.E. I cannot substitute the window with a brick wall, but I can change the window with a newer one.
So a new sealed and safe "showcase" will substitute the actual one, maybe in PVC or wood.
Is it a good idea to build, a meter or so inside of the space, a new massive wall to complete the isolation outer shell? 2) Those pillars are a bad business, but I have to deal with them. They are a rigid connection between the studio space floor and the upper floor, and I suppose they represent a flanking path. I'm thinking to design the rooms to let the pillars to be outside the inner isolation shell of course, but what about the floor? Wouldn't it be necessary to decouple it as well from the pillars? I was thinking about a giant drum riser as a new floor inside the inner shell isolation walls. It would be handy also to make room for the audio cables... I don't know, I'd really appreciate your advice
3) I think I have identified my isolation goal with 60dB of transmission loss.
I would like to make the isolation walls with 4 sheets 15mm of fire rated drywall and steel framing, inside-out. Same for the ceiling but with wood beams instead of steel.
It means a total of 60mm - about 52.8kg/sq. meter surface density - using the data of Knauf gypsum board easily available here were I live (docs I found are in the Italian version of the website, the published density is 880kg/m3)
Will I achieve with this system enough mass to reach the TL requested?
I would also like to not waste any space, and so mantain the iso walls MAM system as thin as possible. In my initial plans, the air cavity is 140mm wide (5,5 inches) in the closer spots, and in some spots it should be around 900mm (35 inches) wide (but without insulation, to make a passage for indipendent live room and control room entrances ).
In the first case (140mm - 5,5inches wide cavity with insulation), the calculated MAM resonance is 18.7Hz.
In the second case (900mm - 35 inches wide cavity without insulation), the calculated MAM resonance is 10.5Hz.
Both of these calculations were made using the surface density of the weakest wall of the external shell.
What of these two values will be the closest to the final resonance of my wall isolation system?
4) In my idea, the HVAC duct runs will be above the iso rooms.
Will be 30cm (11 inches) enough? Also, is there a problem placing the ducts inside the MSM cavity?
5) In the back of the building, there is a glass door, in the external wall. Due to its orientation, it's a very useful natural light source. Is it possible/is it a good idea to mantain this glass door (with proper glass thikness, airtight construction and a second internall glass door for the iso shell)?
Also that door I think will be needed because the external units for the HVAC system should be placed in that side of the building.
At this design stage these are the "blocking questions" that I have to solve before I can move on adding more details to the designs...
Sorry for the long post and thank you for reading!!
P.S. Sorry but I didn't manage to make readable images with a resolution below 750pixel wide, I hope the post isn't difficult to read for anyone.
Marco
Wow! That's REALLY loud! And that's just ambient sound? With no noise at all being made inside your place?
great! I'll research for some designs and propose them when other major aspects of the live room will be less smoky.
I'll do ASAP to picture a better data set of the acoustic performance of the actual structure.
