The Cottage Studio Build

[xSpace]

"The new garage will be 19' x 27' with 10' header height and a roof with an 8/12 pitch."

See this started out a garage and the garage mentality has not modified the want for an acoustic environment. And you will or hopefully can, forgive me when I ask or give statements that may not seem fit to you as the builder/contractor/owner whichever it is.

As you were already told you missed a HUGE opportunity to isolate the slabs, interior from the exterior. But I will take that even a few steps farther. It would not have made any significant change in the structure to pour the footing and lay a poured block foundation. Once that poured block foundation was in place you have the exterior dimensions to pour the interior slab, with no direct contact to the exterior.

But even beyond that not only was this "attempt" not approached, the slab is so tied together with rebar that there is no way you will ever get the exterior side of the structure out of the interior side, why was that done? And don't give me that California stuff like rebar is going to modify the ability of concrete to withstand an earthquake. If that were true the whole structure would be concrete and rebar.

I will submit a few more things before I move on to the reason my knees jerked, if you will

That roof is completely un-braced. You are not only not ready for an inspection you are fooling yourself if you think that it will pass. Granted the process may be different due to regional administration tactics, but the plumbing/electrical/HVAC gets signed off before a final framing inspection.

Why you ask? Because of the loads placed on the structure. Again, you guys may have a three step framing inspection, which just goes to show why Californians and the delegates that choose or were chosen to represent her have California in the situation they are currently in.

Let me preach on...

... The plans called for "balloon framing" walls on the front and back because of the height of the building, the front and rear walls could act like large sails and destroy the structure.

Balloon framing has long since gone out of style and is outlawed. Typical platform or western framing is the standard. No big secret why since you effectively create a chimney that air/fire can pass through unrestricted into the upper areas of the structure allowing that fire to spread.

To add more mass with a "sistered" stud only adds to the potential for this weather beaten wall to shift, other than that it will do little. I refer you back to the roof bracing that has not been seen as of yet but will also submit a simple solution.

If you guys would have actually been building an acoustic environment instead of a garage (and we have not even addressed the reduced TL that the roll up door is going to produce) your, for lack of a better term, architect would have suggested a vaulted ceiling that is supported with poles embedded in the Earth that would have supported the roof and added the shear ability to the structure.


That said...it is not uncommon for a gable ended roof to be braced and to have the ability to support said roof against inclement weather.

I submit to you I live in Hurricane alley and have worked on gable houses for decades with no loss. Saving a falling tree or twelve:)

[beau]

Thanks! I had a feeling that was the answer....

Right now, it's half inch plywood as the existing sheathing. Would it be best to do another half inch layer? or 3/4"? Osb or Plywood?

Beau

[beau]

Hi xSpace, I'll try to answer best I can..

"The new garage will be 19' x 27' with 10' header height and a roof with an 8/12 pitch."

See this started out a garage and the garage mentality has not modified the want for an acoustic environment. And you will or hopefully can, forgive me when I ask or give statements that may not seem fit to you as the builder/contractor/owner whichever it is.

Owner

As you were already told you missed a HUGE opportunity to isolate the slabs, interior from the exterior. But I will take that even a few steps farther. It would not have made any significant change in the structure to pour the footing and lay a poured block foundation. Once that poured block foundation was in place you have the exterior dimensions to pour the interior slab, with no direct contact to the exterior.

But even beyond that not only was this "attempt" not approached, the slab is so tied together with rebar that there is no way you will ever get the exterior side of the structure out of the interior side, why was that done? And don't give me that California stuff like rebar is going to modify the ability of concrete to withstand an earthquake. If that were true the whole structure would be concrete and rebar.

After almost a year of trying to get a permit for a simple garage, this design got the go ahead, so I had to roll with it.

I will submit a few more things before I move on to the reason my knees jerked, if you will

That roof is completely un-braced. You are not only not ready for an inspection you are fooling yourself if you think that it will pass. Granted the process may be different due to regional administration tactics, but the plumbing/electrical/HVAC gets signed off before a final framing inspection.

yes, rough framing inspection comes first. I am not sure what bracing is, but the way the roof is built is the way the structural engineer specified it to be. Let me know if there is any details about the roof I could show you to help clarify anything.

Why you ask? Because of the loads placed on the structure. Again, you guys may have a three step framing inspection, which just goes to show why Californians and the delegates that choose or were chosen to represent her have California in the situation they are currently in.

I totally agree... California is in sad shape, and I'm not sure the people at the permit department can tie their own shoes...

Let me preach on...

... The plans called for "balloon framing" walls on the front and back because of the height of the building, the front and rear walls could act like large sails and destroy the structure.

Balloon framing has long since gone out of style and is outlawed. Typical platform or western framing is the standard. No big secret why since you effectively create a chimney that air/fire can pass through unrestricted into the upper areas of the structure allowing that fire to spread.

Ya, I read the same thing about balloon framing. It's obviously not outlawed here, but even my contractor was surprised about the balloon framing, hence the misunderstanding.

To add more mass with a "sistered" stud only adds to the potential for this weather beaten wall to shift, other than that it will do little. I refer you back to the roof bracing that has not been seen as of yet but will also submit a simple solution.

If you guys would have actually been building an acoustic environment instead of a garage (and we have not even addressed the reduced TL that the roll up door is going to produce) your, for lack of a better term, architect would have suggested a vaulted ceiling that is supported with poles embedded in the Earth that would have supported the roof and added the shear ability to the structure.

The vaulted ceiling was my original plan. I was told that with all of the beams it would take to support it, it would be very costly. However, at this point, I'm starting to feel like this plan is rivaling the original quote.

That said...it is not uncommon for a gable ended roof to be braced and to have the ability to support said roof against inclement weather.

I submit to you I live in Hurricane alley and have worked on gable houses for decades with no loss. Saving a falling tree or twelve:)

Thanks xSpace, let me know if there is any other information you need to keep helping. Even though I may not be able to implement some of the advice, I still very much appreciate it.

I'm at the point where I just need to get the garage done, so I can start the studio build and get back to work.

Thanks again,

Beau

[beau]

We passed our framing, sheeting and roofing inspection, as well as our "green inspection." So now we have the green light to finish the rest of the garage!

Regarding the extra layer of plywood / osb on the outside of the garage, it turns out I'll be substituting the extra layer of plywood / osb for a layer of 5/8" exterior drywall that must be placed under the hardy plank siding. Apparently, the hardy plank siding is not 1 hour fire rated, so in order to meet the Los Angeles 1 hour fire rating, the construction from the outside in will look like this... hardy plank siding, 5/8" exterior fire rated drywall, 1/2" plywood sheeting, 2"x6" stud with insulation, 5/8" fire rated drywall. The code says that only the walls 3' from the property line must be constructed like this, but my plan is to continue the external drywall all the way around the outside of the garage, beefing up the outer layer. Unfortunately, the internal layer of drywall must be installed to pass inspection, but that will be coming down once final inspection is passed.

My question now, is about caulking. As I understand it, the intention is to caulk all seams and joints, right? so basically any place where 2 pieces of material join together? I have a few cases of green glue acoustical caulk, would it be best to use this caulk for all caulking duties? or are there better caulks for different duties?

Thanks again,

Beau

[beau]

Ok... quite a few months have gone by, and here is where I am at.

Garage Construction... Complete.
Inspections ......Complete.
Certificate of Occupancy received.

Studio Construction.
Control room framed, with 2 layers 5/8" drywall caulked with green glue acoustic sealant at every seam with the exception the wall on the side of the iso booth. (Currently this layer has only one layer of drywall, but will have 2 or possibly 3 depending on the answers I get on the next post.) Here are some photos.... and in the next post, I will post the questions I have regarding isolation concepts for the iso booth.

[beau]

So my question is regarding the isolation between the control room and iso booth to the outside / airlock.

Is this proposed green wall necessary? Assuming the iso booth wall would be 3 layers 5/8" drywall on the inside, 2x4 studs, with ultratouch insulation between studs, this would give me a 2 leaf system all the way around... so my question is this green wall extending from floor to ceiling be helpful with adding isolation from sounds coming through the entry door?

Thanks in advance,

Beau

[Soundman2020]

Yes, it is necessary. If you don't have that, the your entry door opens directly into your air gap...

- Stuart -

[beau]

Thank you so much Stuart!

Yesterday I finished the 2nd and 3rd layer of drywall on the control room wall that borders the iso booth. I also finished framing the iso booth. I will post pictures shortly.

Beau

[beau]

Hey all,

So It's been quite a while, and I've made quite a bit of progress. Completed construction on the control room and iso booth. Tracked a few records in there and now starting construction on the upstairs lounge and bathroom.

I'm going to take some measurements and post them as soon as I get a a free minute. I've been struggling with getting rew to work correctly. The impulse response keeps coming up unusable. I'm going to dive in and review the tutorials.

My main issue I am noticing is an issue of low frequencies reflecting off of the rear wall causing a null at the mix position. I came to this theory because when I roll in my chair towards the rear of the room, the null frequency rises. At my mix position it is around 114hz, and as I roll my chair back to the rear of the room, it goes up to around 200. So it's really just within that range. Moving left to right and standing or sitting has no effect.

Right now, the entire rear wall is covered with 14 inches of pink fluffy insulation from floor to ceiling, wall to wall.

All walls are inside out walls with 3.5" ultratouch between studs, faced with fabric.

Speakers are flush mounted.

Below is a picture of the floor plan and dimensions. The ceiling (shell) has a height of 9.5'

I'm wondering if some of the Hidley / Newell wave guide hangers instead of the existing insulation would help with the low frequency reflections coming back off the rear wall. Possibly a low frequency diffuser? Something to guide the low frequencies away from my mix position.

[beau]

Ok, so here are some photos of the control room in it's current state. It's messy and still needs some finishing work cosmetically. But this will hopefully give you a clearer picture of the room. As all home studios are, it is a work in progress, but I had to get working on projects I was committed to. I would like to add some diffusion to liven up the room a bit, being that it is completely absorbent with the exception of the flush mounted wall and the floor.

Treatment so far.
The blue area above the mix position is filled completely with pink fluffy insulation. sloping from 6" -24"
The center section between the flush mount walls is filled with 20" of pink fluffy insulation.
The side walls are filled with 3.5" ultratouch
Rear wall is 14" pink fluffy from floor to ceiling, wall to wall
The angled grey sections of the ceiling are .5" mdf panels filled with ultratouch and pink fluffy.
The grey flat section above the couch is 14" of pink fluffy.

Again, My question is regarding the low frequency reflections coming from the rear wall. From the research I have done so far, I'm thinking the newell rear wall absorber and hangers might be an option, But I'm having trouble finding any data on how much space is needed for them, as well as exactly what materials would provide absorption / diffusion of 100-200hz. I have read that it is questionable whether or not hangers work better than super chunk / wall to floor pink insulation.

Thanks in advance.

Beau

[Soundman2020]

I've been struggling with getting rew to work correctly. The impulse response keeps coming up unusable. I'm going to dive in and review the tutorials.

What type of computer are you using? Mac or PC? There are issues with Java on some versions of the Mac OS: it was not implemented correctly for handling sound streaming, so you need to jump through hoops to make it work right. I've been through that with a few builds lately, and the problem can present more or less the way you describe. So if you are on Mac, then let me know and I'll PM you the work-around. But if you are on a Windows PC there should be no problems with Java, so it would be most likely be a setup or calibration issue.

My main issue I am noticing is an issue of low frequencies reflecting off of the rear wall causing a null at the mix position. I came to this theory because when I roll in my chair towards the rear of the room, the null frequency rises. At my mix position it is around 114hz, and as I roll my chair back to the rear of the room, it goes up to around 200.

Then it isn't really one issue, but rather several: it's not the frequency of the null "changes", but rather that you are moving from one null to another, with each one being at a different frequency. What are the final dimensions of the hard boundaries of the room inner-leaf, excluding all treatment? It looks like 17'6-1/2" long by 16' 8" wide: correct? But what's the height? And where is your head located in that room? (how many feet/inches from the rear hard boundary, and above the floor?

I'm wondering if some of the Hidley / Newell wave guide hangers instead of the existing insulation would help with the low frequency reflections coming back off the rear wall. Possibly a low frequency diffuser?

I though the original plan WAS hangers???? How did that get changed to very thick insulation? Also, what type of insulation is it? (fiberglass/rockwool, density, etc.). Any air gap behind? I would suggest maybe trying very large poly-cylindrical diffusers on the rear wall, or maybe large pyramid diffusers. But first I would get REW working and see what the actual problems really are.

Something to guide the low frequencies away from my mix position.

If it is a modal problem, then you can't "guide it away" anyplace. You can either damp it, or try to break it up. And damping doesn't seem to be working...

The blue area above the mix position is filled completely with pink fluffy insulation. sloping from 6" -24"
The center section between the flush mount walls is filled with 20" of pink fluffy insulation.
The side walls are filled with 3.5" ultratouch
Rear wall is 14" pink fluffy from floor to ceiling, wall to wall
The angled grey sections of the ceiling are .5" mdf panels filled with ultratouch and pink fluffy.
The grey flat section above the couch is 14" of pink fluffy.

To me, it sounds like you might be over-doing the absorption somewhat. That room must be sounding pretty dead right now. You probably need to liven things up a bit in places. But once again, REW will tell....

But I'm having trouble finding any data on how much space is needed for them, as well as exactly what materials would provide absorption / diffusion of 100-200hz. I have read that it is questionable whether or not hangers work better than super chunk / wall to floor pink insulation.

Hangers done right (the John Sayers way) can be very effective for low frequencies. Materials are 1/2" Homasote for the core, then at least an inch (better 2" if you have the space) of insulation on each side, hung from wires to swing freely, and spaced at the 1/2, 1/4, 1/8, 1/16, 1/32 wave points across the rear wall.

- Stuart -

[beau]

Thank you Stuart!

I am running a macbook for measurements. I was able to get rew to work using windows on bootcamp. Here is a link to impulse responses taken from 9, 10, 11 and 12 feet from the rear wall. All measurements are taken 4' from the floor. (I couldn't upload them to the forum)

http://www.beauburchell.com//Impulse%20 ... -11-13.zip

Room Dimensions. Yes, the room is roughly 16'8" wide, 17'6" long, 9'5" tall. My listening position is 4' from the floor, roughly 10'-12' from the rear hard boundary.

The rear wall is as follows. from outside in.
2 sheets 5/8" drywall, 2x4 studs, 3.5" ultra touch insulation between studs, pink r30 fiberglass insulation, stud frame with ultratouch between the studs, fabric. No air gap.

Yes, It is quite dead in here, and I would like to liven it up a bit, but my main concern is this low frequency null.

I don't know why I didn't do hangers. I want to say it is because the internet told me there was not enough test data on them, and that the superchunk style wall was tested and just as effective. I also couldn't find any information on how to tune them, or how much space was needed, or what sizes they should be.

That being said, I think I could give up another 9" of floor space to make the rear wall absorption / trap more effective. I could also give up some corner space, although the visible corners at this point are not the actual hard corners.

Hopefully the IR files will will work.


Thanks again,

Beau

[beau]

here are 3 waterfall graphs from 9, 10 and 11 feet from the rear wall. It looks like the best place to be would be 9 feet from the rear of the room because of the nasty null that 11ft has at 105hz. 10 gets a little better at 117hz. but the smallest null is at 125hz in the 9 feet position. I would like to think by absorbing from 100-150 hz, these nulls should decrease. Does that sound reasonable? or am I way off in that thinking?

B

[Soundman2020]

Glad to see that you got REW working! That's great. Now it will be easier to actually understand what you are dealing with.

Actually, you are sort of going about things backwards here: focusing on only one single aspect of acoustics, while ignoring all the others, which are equally important, or maybe even more important!

For example, placing your head at 9 feet from the rear wall might well be good from the modal situation, but it also places you too close to the rear wall, where early reflections will be arriving in less than the Haas time, and therefore coloring the perceived sound, as well as moving it spatially. Also, that places you too far away from the speakers, messing up your geometry (the famous "triangle"), and possibly placing you beyond the critical distance (in the acoustic far field, when you should be in the acoustic near field), as well as moving your first reflection points further back in the room, and very likely also changing your perception of reflections (from the impulse response graphs). Among other things....

What you are trying to do is to treat the room first, then trying to find a place where it doesn't sound too bad, to set up your listening position. In reality, you should do it the other way around: set up your listening position in the best position first, then treat the room accordingly.

Also, from those graphs it seems that you have the modal issues fairly well under control, (although it would be good to see how things look at lower levels, say down around 50 dB, or even 40), so that isn't even your problem! Your modes seem to be well damped, and hardly evident at all. So very likely what you are seeing is something else, such as some form of SBIR.

What speakers are you using? (make and model).

- Stuart -

[beau]

Thanks Stuart!

I do plan to focus on the whole spectrum, and I will be here asking questions when I get to it.

Listening position, I will mark my listening position and report back later this evening. I am going to re-measure tonight because I think my marker for measurements may have been off a whole foot, meaning 10ft from rear wall is actually 11ft from rear wall... etc... So I'm going to re-measure to be sure.

That being said, I will take some measurements at 40 and 50db tonight. Is there any other measurements or methods you would like me to use or try?

Beau