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 Post subject: Is this studio possible?
PostPosted: Wed Jul 05, 2017 8:13 am 
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Joined: Thu Mar 24, 2016 1:47 am
Posts: 9
Location: Minnesota, USA
Hello All,
I am a 56 year old drummer,songwriter, and singer. I have moved to the uptown area of Minneapolis, MN which is heavily populated. I just received permission to convert a small carriage house into a studio, which is located behind the home that I moved into. The outside dimensions of the building are 22' 2"w x 18' 4"d x 8'h (rising to 15' at the peak). It was built in the early 1900's with actual 2x4 framing. It has a poured concrete slab for the floor.

Because of the size, my goal for this room is a songwriting/recording workshop. It will contain a drumkit (fully mic'd), an Imac, a Focusrite Saffire preamp, a M-Audio keyboard, and a pair of Alesis M1's. It will have a small iso booth in a corner for vox/guitar. I don't plan on any serious mixing, as there is not enough room. I will have to mix elsewhere. Possibly a decade from now I will add a separate control room building, as time/money allows. My budget is $15,000, which will include a small HVAC system. If this isn't enough, then so be it....I'll figure it out. The 1st phase is to build a 12x16 shed in the backyard to accommodate everything that is in there now. So before I do anything, is this studio possible? Here are some questions:

1. I am surrounded by apartment buildings. Two of the buildings are 25' from the carriage house. Is this too close?

2. When I research STC ratings (Rod Gervais's book and the web), I don't see any actual wood-stud built wall drawings/diagrams showing more than 63 db of isolation. Can anyone refer me to drawings depicting higher STC?

3. With my drumming at 108 db and with 63 db STC-rated walls (MAM double walls-double sheeted on each exterior side), then standing 24 feet from the studio I'm at 27db. Maybe I have a bass or guitar amp (in the booth) as I'm drumming. I would assume that will increase my overall decibel level. If I add another layer or 2 to each stud wall, will this adequately increase my STC rating??

I can't spend all the time and money unless I know that I won't be bothering anyone with volume. All it takes is one unhappy neighbor, and I have 20 or so.

Thank you in advance for taking the time to read this. This is the best resource on the entire internet. Hands down.....

Sincerely,

Bill
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garage reduced.jpg


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PostPosted: Thu Aug 24, 2017 7:05 am 
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Quote:
I just received permission to convert a small carriage house into a studio,
Looks like it has pretty good possibilities!

Quote:
It will contain a drumkit (fully mic'd), ... I am surrounded by apartment buildings. Two of the buildings are 25' from the carriage house.
OK, so serious isolation is needed here! Drum kits and close neighbors do not mix well... Visions of pitchforks and flaming torches.... :)

Quote:
Is this too close?
Yep! Tell them all to move further away! :shot: :yahoo: :cop: :cen: :blah:

OK, so that's probably not an option ( :roll: ). So high isolation is your only real possibility here.

Quote:
2. When I research STC ratings (Rod Gervais's book and the web), I don't see any actual wood-stud built wall drawings/diagrams showing more than 63 db of isolation. Can anyone refer me to drawings depicting higher STC?
First, forget STC. It is no use at all for telling you how well your studio will be isolated. STC was never meant to measure such things. Here's an excerpt from the actual ASTM test procedure (E413) that explains the use of STC.

“These single-number ratings correlate in a general way with subjective impressions of sound transmission for speech, radio, television and similar sources of noise in offices and buildings. This classification method is not appropriate for sound sources with spectra significantly different from those sources listed above. Such sources include machinery, industrial processes, bowling alleys, power transformers, musical instruments, many music systems and transportation noises such as motor vehicles, aircraft and trains. For these sources, accurate assessment of sound transmission requires a detailed analysis in frequency bands.”

It's a common misconception that you can use STC ratings to decide if a particular wall, window, door, or building material will be of any use in a studio. As you can see above, in the statement from the people who designed the STC rating system and the method for calculating it, STC is simply not applicable.

Here's how it works:

To determine the STC rating for a wall, door, window, or whatever, you start by measuring the actual transmission loss at 16 specific frequencies between 125 Hz and 4kHz. You do not measure anything above or below that range, and you do not measure anything in between those 16 points. Just those 16, and nothing else. Then you plot those 16 points on a graph, and do some fudging and nudging with the numbers and the curve, until it fits in below one of the standard STC curves. Then you read off the number of that specific curve, and that number is your STC rating. There is no relationship to real-world decibels: it is just the index number of the reference curve that is closest to your curve.

When you measure the isolation of a studio wall, you want to be sure that it is isolating ALL frequencies, across the entire spectrum from 20 Hz up to 20,000 Hz, not just 16 specific points that somebody chose 50 years ago, because he thought they were a good representation of human speech. STC does not take into account the bottom two and a half octaves of the musical spectrum (nothing below 125Hz), nor does it take into account the top two and a quarter octaves (nothing above 4k). Of the ten octaves that our hearing range covers, STC ignores five of them (or nearly five). So STC tells you nothing useful about how well a wall, door or window will work in a studio. The ONLY way to determine that, is by look at the Transmission Loss curve for it, or by estimating with a sound level meter set to "C" weighting (or even "Z"), and slow response, then measuring the levels on each side. That will give you a true indication of the number of decibels that the wall/door/window is blocking, across the full audible range.

Consider this: It is quite possible to have a door rated at STC-30 that does not provide even 20 decibels of actual isolation, and I can build you a wall rated at STC-20 that provides much better than 30 dB of isolation. There simply is no relationship between STC rating and the ability of a barrier to stop full-spectrum sound, such as music. STC was never designed for that, and cannot be used for that.

Then there's the issue of installation. You can buy a door that really does provide 40 dB of isolation, but unless you install it correctly, it will not provide that level! If you install it in a wall that provides only 20 dB, then the total isolation of that wall+door is 20 dB: isolation is only as good as the worst part. Even if you put a door rated at 90 dB in that wall, it would STILL only give you 20 dB. The total is only as good as the weakest part of the system.

So forget STC as a useful indicator, and just use the actual TL graphs to judge if a wall, door, window, floor, roof, or whatever will meet your needs.

OK, not to answer the question you tried to ask: Is it possible to have high isolation in a building with wood-framed walls and wood siding? Answer: Yes it is. It needs careful design, careful construction, and a decent sized budget, but it can be done.

Quote:
3. With my drumming at 108 db and with 63 db STC-rated walls (MAM double walls-double sheeted on each exterior side), then standing 24 feet from the studio I'm at 27db.
Assuming you replace the phrase "63 db STC-rated walls" with "walls that are rate to proved 63 dB transmission loss", then the answer is yes, sort of. That would give you about 36 dBC at the 24 foot mark (assume 3 dB reduction per distance doubling, starting at 3 feet).

Quote:
Maybe I have a bass or guitar amp (in the booth) as I'm drumming. I would assume that will increase my overall decibel level.
Yes. And since bass is a more of a constant level, while drums are intermittent impacts, you'll have a basic level of, say, 100 dB from the bass, with transients hitting 110, maybe 115, from the drumming.

Quote:
If I add another layer or 2 to each stud wall, will this adequately increase my STC rating??
Yes, no, maybe, but not really... :) Sorry to be obtuse, but it's not that easy. There are many factors in play. You'd have to do the math for the actual wall system that you are planning, then draw the projected TL graph, compare that to the spectrum of sound you will be creating (bass + drums), and compare that to the Fletcher-Munson curves (or equal loudness curves if you prefer), and you can have a pretty good idea of what your neighbors will perceive, in their buildings that tower above your roof, as they whittle new spears and stakes, and sharpen their pitchforks....

Quote:
All it takes is one unhappy neighbor, and I have 20 or so.
so 20 javelins, 20 spears, 20 stakes, 20 pitchforks, 20 blazing torches... :) Yup, you better do a good job of designing your isolation system!


- Stuart -

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I want this studio to amaze people. "That'll do" doesn't amaze people.


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PostPosted: Wed Aug 30, 2017 6:29 am 
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Joined: Thu Mar 24, 2016 1:47 am
Posts: 9
Location: Minnesota, USA
Thank you for responding Stuart....and thanks for the STC clarification. This will be quite a project. It will have to be done in many steps. The first step is cleaning the place out-which I have begun. It is jam packed with old tenant-type stuff dating back to the 1980's. Then I have to build a big shed to accommodate the small workshop and lawn tools exist in the garage now. After the place is cleaned out, there is a brick built chimney and old sheetrock that has to be removed. Then I can determine if the existing walls/roof rafters are even capable of supporting the mass needed for proper TL. If not, then it's start over, from the ground up.

Since my OP, I have secured a rehearsal room rental where I have my drums mic'd up (poor acoustics, good enough for now). I write music and lyrics in my bedroom. My only need at this point is a decent sounding iso booth for vocals. I am planning on building the John Sayers booth plan (thank you Mr. Sayers!) with some modifications as I don't have enough space for his size room. I will probably move this booth into my new studio when that gets completed.

Question(s):
What is the proper forum protocol?......
Should I start a new post for this iso booth?
Should I add to John's original 2010 post?
Should I continue on this post?

Please advise.....

Thank you for taking the time to read this.

Sincerely,
Bill


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PostPosted: Fri Sep 01, 2017 2:23 am 
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Location: Santiago, Chile
Quote:
What is the proper forum protocol?......
Should I start a new post for this iso booth?
It's better to keep all of your posts about your studio together in one thread. IT makes it easier for others to follow along, and it makes it easier for YOU as well, as you don't get confused trying to remember which thread you asked which question in... and then lose continuity on your own thread"

Quote:
Should I add to John's original 2010 post?
You could add a link here that points back to that thread, and even copy images or quite text from that one over here. Once again, for continuity in your own thread, but also saving people the hassle of going over there to see something important that you are talking about.

Quote:
Should I continue on this post?
:thu: definitely!


- Stuart -

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PostPosted: Mon Sep 04, 2017 2:10 pm 
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Joined: Thu Mar 24, 2016 1:47 am
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Location: Minnesota, USA
Okay Stuart! Here we go.....
I am building a vocal booth in my bedroom with a $1500.00 budget. It is based on John Sayers most elegant design he posted in 2010:

https://johnlsayers.com/phpBB2/viewtopic.php?f=1&t=14147&start=75

Here is a snapshot of his booth:
Attachment:
John%20Sayers'%20Booth.JPG


My room sits in a house built in 1901. It consists of actual 2 x 4 dimensional lumber, and plaster/lath walls and ceilings. The foundation has settled over the years leaving my bedroom floor uneven and not level. Changing the floor (or any other part of the room) is not an option, so I am forced to start with a sub frame, then level it, and then sheet it. I am planning to build the floor (thanks again to John Sayers) like this:
Attachment:
floor framing.png


As much as I love John's booth, it was too big for my room, so I had to redesign it. His booth had two layers of 1/2" sheetrock, then 2x4 framing with insulation. This would not provide enough TL for my situation as I don't want to disturb my roomates. I'm guessing his TL is approximately this (I know it's STC Stuart, but it was all I could find):
Attachment:
double sheet example.png


Here's a pic of my room with the maximum space (outlined) available for a booth (approx 6'-9" x 7'-2"):
Attachment:
myroomwithboothposition.jpg


Here's a skp pic of the booth in my room (I decided to go without the booth window):
Attachment:
skp my room with booth.png


Here are some other views:
Attachment:
topview no sheeting.png

Attachment:
front view.png

Attachment:
diagnal top.png


These are the amounts of TL that I seek:
Attachment:
TL hopes.png

But I am going to initiate Mr. Sayer's famous "inside out walls" and want to do this:
Attachment:
wall edited.jpg



I plan on building my own doors referring to Stuart's DIY door build post (which I can't find now) and also HVAC using the boxes John has in his booth. Also not shown is the fiberglass between the walls/ceilings and the rigid fiberglass/resonators lining the inside walls and ceiling. I am waiting to place these in my drawing as I am unsure of a few things:
1. Is approx 6'D x 5'W x 7'H enough space for a vocal booth?
2. I can't find any specific data referring to TL and John's "inside out walls". Is it fairly comparable to the same data not turned inside out? (I am loosing 3.5" of air space).
3. I realize that I am not leaving much air space between the booth and two of the walls. These are both exterior walls and I am not as worried about the neighbors or the outside world. Does this decrease the TL for the other two walls facing my bedroom door (and roomates) and ceiling?

Thank you again for taking the time to look this over,

Sincerely,

Bill


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