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PostPosted: Mon Jun 11, 2018 12:57 am 
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Joined: Fri May 25, 2018 12:27 pm
Posts: 3
Location: Birmingham, AL
Hey, guys!

I am in the construction process of my plans. My buddy is an architect and he drew up the blueprints; I've attached those below. My goal is to build a project studio out of my shed.

I have no idea how loud I’ll be monitoring, but I will be recording instruments like drums and bass guitar. I do have neighbors. All 3 are approximately 100’ to 300’ from the shed. I haven’t measured, just an estimate. Pic of shed for reference. Got one on the other side of that brushy area, one behind me as i’m standing taking the picture, and one to the right of the shed about 200’ or 250’.

Final dimensions would be:
Length: 18.55'
Width: 10.55'
Height: 8' and 9.33'

Shed, overview: https://i.imgur.com/S8tQhfa.jpg

Attachment:
35058201_10156506315541514_8772806826220584960_n.jpg


Here are snapshots from the blueprints, as well:

Cross Section: https://i.imgur.com/2u4vLaP.png

Attachment:
Cross Sectional Area Plan.png


Floor + Walls Cross Section: https://i.imgur.com/m4BXP65.png

Attachment:
Floor + Wall Cross Section Plan.png


Vault: https://i.imgur.com/N5U5te9.png

Attachment:
Reflected Ceiling Plan.png


Overhead: https://i.imgur.com/vfAqmrb.png

Attachment:
Overhead Plan.png


Three primary concerns and questions:

  • As is, we're primarily building new walls on the inside, as well as vaulting an 11' center portion of the ceiling to get it a bit roomier (roof is pitched, so can't vault the entire portion of the ceiling or it'd collapse) (see "Reflected Ceiling Plan"). Primarily goal in doing this is to aid in tracking drums - reflections off the ceiling from cymbals would make getting a solid overhead mic sound very difficult with the existing 8' ceiling space, so I figure I can vault it and suspend some 6" traps above where drums will most likely be recorded. A concern of mine with this is that I’ll end up putting a 2’ span of the ceiling center point that runs that 10’ effectively a multiple of the length (18.55’ w.r.t. 9.33’). Not sure how to tackle this!!

  • I’m looking at either ATC SCM25a’s, Focal SM9s, or Amphion Two18s. If I go with the ATC SCM25a’s, can I soffit mount them? If so, how? If no, can I hang them from the ceiling and angle them down at me? Pic attached for reference. And if I DO soffit mount them, should I be looking at more-involved plans with splayed walls? I’m reaching the end of my budget for all this and I’m only going to be living here for about 3 or 4 years. Might not be cost effective to put more than I already have into this (~$2,000).

  • How much of the windows can I keep? Goal is STC 65 or so. STC 75 would be great, but I don't know if I can get there with the vault + windows. Plan is to build in super thick shutters so I don’t have to lose all of my daylight. Just wondering how effective this’ll be and what I end up trading off.

Current state of shed: https://i.imgur.com/N6xHOJE.jpg

Attachment:
34640446_10156499511176514_7737025443601055744_o.jpg

Potential Monitor Hanging Situation: https://i.imgur.com/N6xHOJE.jpg

Attachment:
34818934_10156505141346514_901583338454646784_o.jpg



Budget is approximately >$3,500. Could go more, I guess, but ideally would not. Currently about $2,700 deep. Have most everything purchased, including the mini split, stud wall insulation, sheet rock, etc.

At any rate, thanks for taking a look! I really appreciate it. I'm looking forward to seeing what kind of info I can get back from you guys. For reference, I studied physics back in undergrad and all of this is totally up my alley. Definitely not my area of expertise, but if you guys wanna get intense with the language and what not then please don't hesitate! I would love to learn as much as I can - really do find this stuff fascinating.

All the best,

Dave


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PostPosted: Mon Jun 11, 2018 5:36 am 
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Posts: 273
Location: Edmonton, Alberta, Canada
Dave! I'm glad you actually came to the forum as I suggested!

So others can pitch in, but I'll take a few minutes here and touch on some things I'm able to answer:

Quote:
I have no idea how loud I’ll be monitoring, but I will be recording instruments like drums and bass guitar. I do have neighbors. All 3 are approximately 100’ to 300’ from the shed.

Without measuring, I can say that you'll definitely need a room in a room design in order to record drums without disturbing neighbours. Another solution would be to communicate with the neighbours and ask them if they'd be tolerant of your noise on drum days (assuming it will only be once or twice a month??) The only issue with this solution would be outside noise getting into your recordings (rain, traffic, etc)

Quote:
Final dimensions would be:
Length: 18.55'
Width: 10.55'
Height: 8' and 9.33'

Your 9.33' is pretty much a direct multiple of 18.55' so that would fail the room mode calculator test :-(

Quote:
As is, we're primarily building new walls on the inside, as well as vaulting an 11' center portion of the ceiling to get it a bit roomier

More room is always wanted/needed, but your width dimension is close to both the 9.33' AND the new potential 11' dimension. Food for thought anyway!

Quote:
If I go with the ATC SCM25a’s, can I soffit mount them? If so, how?

I answered this on Facebook, but again, yes, you can. You could remove the power amp. You just need to ensure proper damping for the ported speaker. You could even leave the power amp on the back if you wanted, just make sure you use chicken wire through any insulation in your soffit to allow the heat to rise off the back of the power amp. There are lots of threads on the forum going over this topic.

Quote:
can I hang them from the ceiling and angle them down at me?

You CAN do whatever you want. No one is stopping you. But, acoustically speaking, this is a horrible idea. It severely reduced the area in which your speakers will sound good to you. So you can't roll back or lean in without drastically changing the way you hear your speakers. Having them parallel to your ears is the only way to really alleviate the said issue. If you do want to tilt your speakers, a good rule of thumb is to stay less than 7 degrees from vertical. The standard height for the acoustic axis of yours speaker is 1.2 meters. Your speakers should never be on the 45 degree line from the corner but be as far apart as possible (between ~28 and 34% the width of your room).

Quote:
How much of the windows can I keep?

For good isolation, none. Honestly though. Unless you want to spend thousands and thousands of dollars building true "studio" windows (MSM style tempered super thick glass), your current windows aren't going to be a viable option here.

Quote:
Goal is STC 65 or so. STC 75 would be great, but I don't know if I can get there with the vault + windows.

STC doesn't apply to full spectrum audio. Also, you can't mention isolation goals in numbers at this point since you haven't taken any measurements. I think at this point you can say that you want to keep outside noise from getting in and to tame loud drums as much as you can within a reasonable budget.

Quote:
Plan is to build in super thick shutters so I don’t have to lose all of my daylight. Just wondering how effective this’ll be and what I end up trading off.

This isn't really a solid idea. The ONLY way to achieve isolation is with mass and an air tight seal (see my comment above about MSM style tempered glass)

Quote:
Current State of Shed

It appears that you've made the mistake most people do. You started building without consulting this forum ;-) It appears that the original walls of the shed have some sort of sheathing on them (plywood? drywall?) and then you have framed up an inner leaf wall.
Two problems exist in the picture:
1. As it stands, you're going to have a three leaf system. As sad as it is to hear this, your isolation after building this other wall will be WORSE than it is right now. What you should have done is removed the sheathing of the original walls, added mass to the outside sheathing. The term used around the forum for this is "beefing up". What you do is use OSB or drywall and install it onto the exterior wall on the inside of the room. You have to cut the material and fit it between the wall studs. Typically people increase the performance (while maintaining space) by applying Green Glue Compound between the layers. You don't screw or glue the new material to your exterior sheathing, rather hold it place using cleats. This adds the needed mass to your MSM system. Without this mass, your isolation will severely be reduced.
2. It looks like your inner leaf frame is flanking your ceiling. So, this is ruining your isolation.

Quote:
Have most everything purchased, including the mini split, stud wall insulation, sheet rock, etc.

What insulation did you buy? The insulation must be effective acoustically speaking at the resonant frequency of the wall. Please tell me you bought heavy fire rated 5/8" drywall. Also, you're going to need two layers, unlike your friends diagram, in order to lower the resonant frequency of your wall low enough to deal with the low frequencies of drums effectively.

Unmentioned in your post:
HVAC

This is the most overlooked aspect of studios. I personally just went and consulted with a studio owner who had his studio flood and wants to rebuild it better than it was (luckily insurance will cover most of the rebuild costs). He bought a studio 2nd or 3rd hand. It was originally built in 1984 and has run as a commercial, loved, well respected studio in my area all these years. I was blown away to learn that it was not a room in a room design. It has horrible/very little acoustic treatment. And the worst part, the live and iso rooms have literally ZERO ventilation. Luckily, the owner said it has always been such an issue that addressing it is his #1 priority.

Having said that, I'm aware that you've bought a split to deal with your heating and cooling, however, they offer no fresh air. You should have 25-30 % fresh air into your room. In order to get fresh air into your room, you obviously have to cut a few big holes into your walls. This will trash your isolation. What you need to do is build some home made silencer boxes. Sadly, they aren't tiny and you need 4 of them per room. You need an outer leaf supply box, outer leaf return box, inner leaf supply box and an inner leaf return box. This is because each box has to maintain the surface density and therefore the isolation of the wall in which it is penetrating. The level at which the boxes isolate is referred to as insertion loss. Luckily, you have an attic/ceiling space in which these boxes could live without eating up space in your room.

I hope I didn't bum you out. This forum is here to help people save money and achieve great results. It's proven time and time again to do just that. Please keep asking questions and keep us posted on you progress (both learning progress and construction progress). Before you continue, I would suggest downloading and learning (at least enough to draw up what you need to) SketchUp Make. With it, you can make all of your measurements, do ray tracing, see exactly where things will fit in your room, and better yet, digitally build things like soffits before doing it in real life. This will save you money and you can confidently build your space knowing it will turn out exactly like your plans.

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PostPosted: Mon Jun 11, 2018 11:59 am 
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Joined: Fri May 25, 2018 12:27 pm
Posts: 3
Location: Birmingham, AL
Gregwor wrote:
I hope I didn't bum you out


TOTALLY bummed me out, actually!! but not enough to make me give up, haha.

i remember watching a vid with Bobby Owsinski about a year and a half ago - bookmarked it specifically for this situation. went back and gave it a watch just a moment ago because i was looking for a specific image, attached that below. totally explains what you were talking about. i'd only be able to get up to 50 STC max without removing the old wall!!!

plan now is to draw out existing power lines with my stud finder, cut the power, take my sawzall and then cut out the drywall between the studs in the older stud wall and push those new panels up against the inside of the outside wall. secure them, install new insulation between the old studs, then push the new studwall out further giving more room since i'll have about an inch of new space, then go from there with relocating the electrical system.

does that sound solid?

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Screen Shot 2018-06-10 at 8.51.45 PM.png


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PostPosted: Mon Jun 11, 2018 2:12 pm 
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Joined: Wed Feb 01, 2017 6:03 pm
Posts: 273
Location: Edmonton, Alberta, Canada
Quote:
TOTALLY bummed me out, actually!! but not enough to make me give up, haha.

Excellent! You sound excited.

Quote:
i remember watching a vid with Bobby Owsinski about a year and a half ago - bookmarked it specifically for this situation. went back and gave it a watch just a moment ago because i was looking for a specific image, attached that below. totally explains what you were talking about. i'd only be able to get up to 50 STC max without removing the old wall!!!

Correct! Remember, STC means nothing in our studio world though as STC doesn't take our entire frequency range into consideration. We just talk in dB's here and assume everyone is talking full-range.

Quote:
take my sawzall and then cut out the drywall between the studs in the older stud wall and push those new panels up against the inside of the outside wall. secure them

Sorry, what "panels" are you referring to? The little sheets of drywall you're cutting out? Re-use them as beef up material? Should work good. The only thing to consider is that they may not be heavy fire-rated stuff. They could be the new cheaper crappy ultra light stuff (about half the weight). Either way, if money is an issue, this is a great way to save cash! To help out, I'd suggest using Green Glue Compound between your exterior sheathing and the beef up material. It will help a lot without eating into your MSM space. Then just use some crappy old little pieces of wood for cleats to hold the beef up material tight to the exterior sheathing. Remember to fill any and all gaps with Green Glue Sealant. Any slightly larger gaps, you should fill with some backer rod then the sealant. Make your room air tight.

What is your plan with the ceiling structure to make a true room in a room construction? I'd suggest building it inside out for countless reasons.

I also never mentioned your floor or your doors.

Regarding your floor, chances are it is a 3/4" plywood or OSB?? That could be a weak link to your isolation. I'd suggest laying down a second layer.

Your doors will have to match the surface densities of your walls. Having barn door style doors like yours are very difficult to seal. I'd recommend going down to a single door. You're going to need another door for your inner leaf as well. These doors are often either homemade or made from commercial solid wood core doors that people add another layer of MDF to the face of. It allows for 2 sets of seals per door. The doors are often held shut with commercial door closers to prevent any thru-door penetrations due to handles/latches.

That covers most of it! Once the room in a room structure is built and you have your ventilation in place, all you have to worry about is acoustic treatment. Having a great mixing room that doubles as a tracking room is hard to do (to have both be amazing). You're probably best off to treat the front of your room so that you don't have SBIR or reflections from your side walls into your ears). Obviously, since this is a smallish room, you will have to bass trap every corner if possible. Probably have broadband absorption on your rear wall to help to attenuate reflections off the rear wall. During drum tracking, you could have this rear wall broadband absorption be variable acoustic panels. The same could be done with any treatment on the walls.

Greg

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PostPosted: Wed Jun 13, 2018 2:59 am 
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Location: Birmingham, AL
So the room is actually incredibly well built already, has r11 in the walls, just going to leave that there. Then throwing in r13 or r14 in my new wall once I get that situated. And it's definitely not the cheap stuff on the walls, haha. The shed was initially a woodworking shop. They did everything to code. Even left 6' between outlets on each wall.

Floor is not just plywood. It's going to be: joists + insulation > 3/4" plywood > carpet > 7/16" plywood > vinyl hardwood imitator on top at the end. Just laying the plywood over the carpet as a subfloor, secured down into the joists.

Ceiling also has insulation on top of it already. Likely just going to leave that as is. Getting pretty burned out at this point!

For treatment, I agree - planned on LEDE principles.

Re: Vault

Principle reason for needing one is to minimize issues when tracking drum overheads. 8' ceilings will lend themselves toward poor cymbal recordings given early reflections off of the ceiling coming back into the overhead mics. I'm probably still going to vault the ceiling, but place 4" Rockboard hanging 4" from the ceiling as a cloud, has an ASTM C423 performance of 1.03 at 125 hz, and the frequency whose wavelength is 9.33' is 105 hz. Pretty close, so I'll just have to experiment with things to see how I can get the most accurate response in the listening position.

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PostPosted: Wed Jun 13, 2018 7:18 am 
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Location: Edmonton, Alberta, Canada
Quote:
So the room is actually incredibly well built already, has r11 in the walls, just going to leave that there. Then throwing in r13 or r14 in my new wall once I get that situated.

Not beefing up the external sheathing will lower your transmission loss performance. Have you investigated how well the r11 performs via an acoustic absorption coefficient chart? If your insulation doesn't absorb well at the resonant frequency of your wall, it is only doing it's duty as a thermal barrier, and nothing for sound. As for your R13 or R14 comment, the same goes for it. Use product that works for the job.

Quote:
Floor is not just plywood. It's going to be: joists + insulation > 3/4" plywood > carpet > 7/16" plywood > vinyl hardwood imitator on top at the end. Just laying the plywood over the carpet as a subfloor, secured down into the joists.

What purpose is that carpet having other than creating a resonant chamber (making your isolation worse)? Also, I've walked on subfloor laid overtop of carpet before and it isn't fun. It's very saggy feeling. If you're wanting a thermal barrier, use a thin purpose built underlay.

Quote:
Ceiling also has insulation on top of it already. Likely just going to leave that as is. Getting pretty burned out at this point!

So you're not going to be building a true room in a room with a new ceiling sitting on top of your inner leaf walls?

Quote:
For treatment, I agree - planned on LEDE principles.

LEDE kind of ran it's course and people started hating their rooms. I'm sure you've read up on different designs so do whatever you think will suit your needs. Again, in my opinion, I would bass trap the hell out of the room and then take measurements with REW and treat accordingly. Any treatment that would hinder my live tracking, I would try to build as variable panels.

Quote:
I'm probably still going to vault the ceiling

Cool cool.

Quote:
but place 4" Rockboard hanging 4" from the ceiling as a cloud, has an ASTM C423 performance of 1.03 at 125 hz, and the frequency whose wavelength is 9.33' is 105 hz.

As long as you do your research and use appropriate materials, you have a fighting chance to make it sound okay!

Thanks for sharing the picture!

Greg

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PostPosted: Thu Jun 14, 2018 12:40 pm 
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Hi there Dave, and Welcome! :)

Quote:
Please read the forum rules for posting (click here). You seem to be missing something... :)

Quote:
My buddy is an architect and he drew up the blueprints;
Please don't take this the wrong way, but is your buddy also a studio designer, or acoustician?

Quote:
I have no idea how loud I’ll be monitoring, but I will be recording instruments like drums and bass guitar.
Once again, please don't take this the wrong way, but how in hell did you manage to design the studio to the point where you have started building it, without even knowing how loud you are, how quiet the law requires you to be, or how much isolation you need? :shock:

Quote:
Length: 18.55'
Width: 10.55'
Height: 8' and 9.33'
That's a fairly decent size for a small home-studio control room, but as Greg pointed out, you have a problem with your ratio! You should do some research on that, then figure out how to fix it.

Quote:
Primarily goal in doing this is to aid in tracking drums -
So it's not a control room? It's a tracking room? Where is the control room going to be?

Quote:
reflections off the ceiling from cymbals would make getting a solid overhead mic sound very difficult with the existing 8' ceiling space, so I figure I can vault it and suspend some 6" traps above where drums will most likely be recorded.
Higher ceiling is pretty much always better for drums, yes. But you might find that 6" of absorption is too much for cymbals: You want to damp the reflections a little, not kill the entire room stone cold dead! :)

Quote:
A concern of mine with this is that I’ll end up putting a 2’ span of the ceiling center point that runs that 10’ effectively a multiple of the length (18.55’ w.r.t. 9.33’). Not sure how to tackle this!!
Is it a live room or a control room? Getting a good ratio for a control room is reasonably important, but not very important at all for a live room.

Quote:
I’m looking at either ATC SCM25a’s, Focal SM9s, or Amphion Two18s. If I go with the ATC SCM25a’s, can I soffit mount them?
Now you are confusing me again! First you had me thinking that this is a control room, but then you mentioned tracking drums so I switched to thinking it must be a live room, but now you are talking about soffit-mounting studio reference monitors, which flips back to it being a control room again! Very confusing... which is it? Control room, or live room? It can't be both.

Anyway: about your monitors: you choose three rather unusual designs! All of them have "features" that make it difficult to do that, such as side porting, and passive radiators on the rear or top. It MIGHT be possible to soffit mount those, but it would be a challenge. All three of those are designed to deal with room issues, and those design features would not be needed if you soffit mount them (except for the SM9), but preventing them from being a problem inside the soffit is another thing. Things start getting complex when there are ports, drivers, or radiators on the side, top, or bottom of the box. If it really does have to be one of those three ONLY, without any other alternative options, probably the Amphions. What amps would you use to drive those? And they are waaaaay beyond your entire budget: each speaker on its own is about what you plan to spend on your entire build... By the time you add in the amp, you'd be eve further out of your budget. So I'm assuming you already own those? The SM9 has the passive radiator on top. That's a challenge, just form the point of view of mounting the thing in a soffit. The radiator is in the way... but it might be possible.. The ATC SCM25a is side-ported: Less of a problem. I would suggest that you take a look at speakers that CAN be soffit mounted without any trouble: Most front-ported, rear-ported, or un-ported speakers can be soffit mounted, as can some that have rear passive radiators.


Quote:
If no, can I hang them from the ceiling and angle them down at me?
No. Never. Not ever. Well, assuming that this is a CONTROL room that is, and that you are aiming to make usable as such. If it is a control room, then speakers must ALWAYS be mounted with the acoustic axis around 120 cm or so above the floor, not tilted. There are multiple psycho-acoustic reasons and acoustic reasons why it is a bad idea to raise speakers then tilt them down.

Quote:
And if I DO soffit mount them, should I be looking at more-involved plans with splayed walls?
Not necessarily. It all depends on which of the many design concepts you decided to use for your room, then also how you intend to actually implement it. Some concepts do require angled surfaces in the room, but it does not have to be the entire wall: even with RFC, or CID, you can still build a rectangular room, then just build additional angled surfaces where needed.

Quote:
I’m reaching the end of my budget for all this and I’m only going to be living here for about 3 or 4 years.
ummmm... not wanting to seem harsh again, but.... you are only just STARTING the build, you don't actually have a design at all, and your budget is already gone? This does not bode well...

Quote:
Goal is STC 65 or so. STC 75
You ave been severely mislead! STC is a terrible system for measuring recording studio isolation. In fact, it tells you pretty much nothing at all about how well your studio will isolate! I can explain that in detail if you want, but basically forget STC, and only ever talk about decibels, or transmission loss curves, when deciding on how much isolation you need. STC does not even take into account half of the entire musical spectrum! No use at all or judging studio isolation.
Quote:
STC 75 would be great, but I don't know if I can get there with the vault + windows.
The vaulted ceiling has no impact on isolation, and neither do the windows, provided that you PLAN and DESIGN the isolation system correctly.

Quote:
Plan is to build in super thick shutters so I don’t have to lose all of my daylight.
That won't work. Sorry. Just plan to keep the windows where they are, but re-build them correctly: IE, with the correct thickness and type of glass for the amount of isolation you need. Yu cannot leave them as they are and still expect decent isolation.

Quote:
Budget is approximately >$3,500. Could go more, I guess, but ideally would not. Currently about $2,700 deep.
So you have maybe US$ 800 left in your budget, and you have not yet even considered ventilation, electrical, windows, or doors? :shock:

As Greg said: "It appears that you've made the mistake most people do. You started building without consulting this forum" :thu:

---

Quote:
TOTALLY bummed me out, actually!! but not enough to make me give up
That's good! A positive attitude is a really good sign that you can make this work! If you design carefully...

Quote:
i'd only be able to get up to 50 STC max without removing the old wall!!!
... and once again, STC is no use at all for measuring studio isolation.. Here's why: 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.

Quote:
has r11 in the walls,
That's wonderful!... for THERMAL insulation, but pretty meaningless for ACOUSTIC isolation...

Quote:
Then throwing in r13 or r14 in my new wall once I get that situated.
Why did you choose that insulation? What acoustic propitiates does it have that made you choose it for your wall? What coefficeint of absorption does it have for each frequency band, and does that tie in with the MSM resonance that you calculated when you designed your wall? :)

Quote:
Floor is not just plywood. It's going to be: joists + insulation > 3/4" plywood > carpet > 7/16" plywood > vinyl hardwood imitator on top at the end. Just laying the plywood over the carpet as a subfloor,
Why? What isolation will that offer? Did you check with a structural engineer to make sure that your floor joists can handle the load? It's just a shed floor, so it likely does not have much spare live-load capacity. You DID check that, right? :)

Quote:
Ceiling also has insulation on top of it already. Likely just going to leave that as is.
What type of insulation? What density? IS it suitable for MSM damping?

Quote:
For treatment, I agree - planned on LEDE principles.
LEDE hasn't been used in decades... That's a very old concept that proved to be uncomfortable to mix in for long sessions, as it sounded unnatural, and fatiguing. Nobody designs pure LEDE rooms these days. Extensions of LEDE and other design concepts are far, far better. Personally, I'm a big an of RFZ.

Quote:
but place 4" Rockboard hanging 4" from the ceiling as a cloud,
Why 4" Rockboard? What are the acoustic absorption characteristics of that, as compared to the spectrum of sound put out by cymbals and snares? Are you SURE that's the correct stuff for that application?

Quote:
has an ASTM C423 performance of 1.03 at 125 hz,
Cymbals put out very little energy at 125 Hz... Kicks, toms, and snares do, but not cymbals or high-hats. Also, is that for A mount, or E-405 mount? Yours is neither of those, so the specs you quote are probably not applicable at all.

Quote:
and the frequency whose wavelength is 9.33' is 105 hz.
Now you lost me! How does that relate in any way at all to the energy spectrum put out by cymbals? I'm not following your logic at all...

Quote:
so I'll just have to experiment with things to see how I can get the most accurate response in the listening position.
Now you lost me even more! I though the purpose of that 4" rockboard was for the CYMBALS, to help deal with reflections off the ceiling, so what does that have to do with the listening position ???? Unless you plan to put the overhead mics at the mix position, I don't see any connection at all. I guess I must be missing something here...

Also, "experimenting" is a really bad way to approach studio design. If you want the most accurate response in the mix position, then download the ITU BS.1116-3 document, and take a look at chapters 7 and 8, so you can see what you should be aiming for, and how to get it. The room should be designed from the start with that response in mind, the fine tuned to get it once it is built. Here's a thread that shows you how the process of tuning a control room should go: viewtopic.php?f=2&t=21368 .

I'm mostly just expanding a bit on what Greg already said, adding my voice to his. It seems that you have run a bit ahead of yourself, and gotten beyond where you should be. It would be a good idea to stop right now, re-evaluate your goals, the read a couple of books, such as "Master Handbook of Acoustics" by F. Alton Everest (that's sort of the Bible for acoustics), and "Home Recording Studio: Build it Like the Pros", by Rod Gervais. The first one will give you the background in acoustics that you need to be able to design a studio, and the second one will give you the basics for actually designing it and building it. Once you have read those, then you can sit down and start actually designing your studio properly, and once the design is in place, then you can build it. If you carry on with your current plain, the results will NOT be what you are hoping You will have wasted a lot of time, money, and effort, and the studio won't be usable. I'm really sorry to have to be the bearer of bad news, and I'm sure you did NOT want to hear me say it, but that is the sad truth. The good news is that you are not too far along that it can't be fixed! If you stop now and learn how to do it right, re-resigning it properly, then you can just undo a bit of what you did wrong, then carry on from there.

- Stuart -

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PostPosted: Thu Jun 14, 2018 1:59 pm 
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Stuart. When you quoted me, it made me realize that I don't have a signature. Now I do :-)

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PostPosted: Thu Jun 14, 2018 4:08 pm 
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Stuart. When you quoted me, it made me realize that I don't have a signature. Now I do
I love it!!! :thu:


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