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jooshy 17 March 2022
Hello! I am setting up a place to record in my basement. I want to know if my idea is flawed and going to have negative repercussions when it’s all put together. I know there are gives and takes of everything and part of the reason I’m setting it up this way is necessity however if it’s going to cause more issues than help I would like to avoid it. I’m going to be setting up in a room we use for storage. I’m going to be setting up in the middle of the room. The dimensions for the room are 11x7 but there’s shelves lining the walls so the floor space is limited. The plan was to use 5 or 6 acoustics blankets to create an enclosed 6x5 space with a ceiling height around 7 ft inside of this room. I’d be hanging them and then also putting one above to act as a ceiling. I will have a full size dense futon cushion mounted on hooks hanging behind me. I know reflection filters are almost useless but I also do have one just in case it will help. I figured if the futon does a decent job of bass trapping, then I should be cool to use the acoustic blankets given that they tend to absorb the higher frequencies. My first concern is that the blankets would absorb too much of the high-endgiven they’re surrounding me, I’m not sure how prominent that issue really is but hopefully y’al have some insight. The other concern being that I know sound will likely leak out from the booth as it’s not sealed, but will that negatively impact the sound or is it to my benefit that I’m putting this inside of a larger room and it’s unsealed? The acoustic blankets will be multiple inches off the wall, the futon will be suspended behind me with potential use of a reflection filter in front of me. Or would I be better off trying to acoustically treat a large room(roughly 11x17) that’s got two walls covered in mirrors as a dance studio with concrete floors? These rooms are connected as well. In the shape of an L. Or maybe some version of my original idea but instead of blankets, somehow using home made panels with OC703/5 and cloth? The problem with that being I don’t have a wall to mount it to without creating one but I can’t put a permanent structure here. Also if anyone has any good resources or information on where I should place my mic for recording once the booth is established? I’ll be doing vocals and playing acoustic guitar. Thank you all for your time and I apologize for not being more concise!

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kmetal Sat, 03/19/2022 - 18:38
Big room will be far easier to work in both acoustically and logistically. Don't waste money on "acoustic blankets". Just get moving blankets if you go that route. Neither the blankets nor the futon cushions will do much bass trapping as they are not optimized for that. A less sealed room can be better acoustically as the walls let some sound out, there's less energy contained within the room. Where id start is the big room with some gobo's. Moveable broadband absorption panels. An perhaps a blanket on top as the roof, if you can't make one from a panel. I'd not worry about the floor, unless it becomes an issue. Reflective floors are common. Owen Corning has changed the formulation of 703/5 and it's no longer the optimal choice. Its worse at low frequency absorbsion now. Instead rockwool Rockboard 40 is preferred as it's about what the old 703 was. The type of insulation you use varies with depth. RB 40 is good to about 4". Rockwool Safe n Sound, from 6-10", standard fluffy fiberglass, 10"+. Those thicknesses are optimal for bass Absorbsion. If you use the wrong insulation and go too thick, it will reflect bass not absorb it. Experiment with different locations in the room, and find what gives you the best balance of sound your looking for. If singing and playing at the same time two mics in figure 8 setting, can give very good isolation from each other.

jooshy Sun, 03/20/2022 - 14:53
Thank you so much this is the most helpful response I’ve gotten. Do do you think the gobos should face me with my back to the corner of the room? And should I build it to where I have 3 panels and they come all the way to the wall or is it ideal that the sound has room to bleed?

kmetal Sun, 03/20/2022 - 22:44
jooshy wrote: Thank you so much this is the most helpful response I’ve gotten. Do do you think the gobos should face me with my back to the corner of the room? And should I build it to where I have 3 panels and they come all the way to the wall or is it ideal that the sound has room to bleed?


Your welcome, glad to assist. A reasonable starting point is to surround yourself on 3 or all 4 sides with the gobos. How close or far from the walls is unique to each room so trial and error is called for there. Going near corners is where bass builds up, which can be a good or bad thing. Generically I'd say try setting up on one side of the room, a few feet from the walls, and maybe off the center line a bit. That's a reasonable starting point. I would also consider the ceiling as a likely culprit, particularly the area right above you. If you can treat that, it's really a good thing.

jooshy Tue, 03/22/2022 - 09:44
kmetal wrote:
jooshy wrote: Thank you so much this is the most helpful response I’ve gotten. Do do you think the gobos should face me with my back to the corner of the room? And should I build it to where I have 3 panels and they come all the way to the wall or is it ideal that the sound has room to bleed?


Your welcome, glad to assist. A reasonable


Hello! I had a couple more questions I hope you could help with! Already very grateful for your time so thank you!! Basically - I was wondering if I should make the gobos cover as much space as possible(ceiling to floor) or if they should have gaps for a stand/wheels. As well as - I’m having trouble finding RB40 but it seems there’s RB60 more easily available and maybe RB80. I was wondering if these would also work and what I should do differently if I use them. I am still looking for 40 though, thank you for your time, it’s truly appreciated.

kmetal Tue, 03/22/2022 - 20:53
If your planning on resting a panel on the top of them to act as a ceiling, then leave clearance for that. Otherwise they can be as tall as you'd like. How much space at the bottom depends on what sort of wheels your gonna use. RB 40 is the preferred stuff. 60 can work but your limited to a thinner panel and less overall low frequency absorption. Rockwool safe n sound is a fine alternative for 6" to 9" thicknesses. You can also use standard fluffy fibreglass. You primary concern is the GFR "Gas Flow Resistivity" of the insulation. That number usually in "rayls" ie 10,000 rayls, determines what the optimal thickness range of the insulation is. The lower the GFR the thicker the panel can be, and more low frequencies you can absorb. Fluffy fibreglass is around 5,000 rayls, safe n sound, around 10,000 rayls, RB40 around 15,000 rayls. You can use those numbers to estimate with acoustic modelling.com and observe the effect that different thickness and GFR has on the Absorption curve. You want a coefficient of at least .80 for the panel to be "effective". And you want to have that down to at least 80hz for vocals and guitar, because that's about the lowest those sounds go. Ideally your coefficient is 1.0 and as low a frequency as possible. When playing around with the calculator, note how the air gap between the panel and wall trades better low frequency absorption for slightly less absorption in the mid range. 12" of fluffy, or 9" of safe n sound makes a nice broadband panel. If you can get to 18" of fluffy you can be effective down to 50hz, which may be useful to tame some room boom.

jooshy Wed, 03/30/2022 - 13:07

kmetal wrote: If your planning on resting a panel on the top of them to act as a ceiling, then leave clearance for that. Otherwise they can be as tall as you'd like. How much space at the bottom depends on what sort of wheels your gonna use. RB 40 is the preferred stuff. 60 can work but your limited to a thinner panel and less overall low frequency absorption. Rockwool safe n sound is a fine alternative for

Thank you! I’m about to build them, And had some questions!
 

I was wondering what layering you’d suggest? I was going to put the insulation in a frame, cover it and be done - but I see people talking about air gaps IN the gobo as well as the pros and cons of having a piece of wood as a backboard. I was wondering what you might think.
 

And I will play with the set up once they’re assembled but was thinking I’d go with a shape similar to \_/ with the back facing the corner to act as a bass trap. I would be facing out of the cubby. Still need to figure out the ceiling coverage but it seems like that’s the way. 
 

My last thought, I have 3 packs of the 2x4 rb40 with 6 pieces per pack. Do you think I should still make the panels (will be roughly 4x6ft per panel, 3 panels) or should I look more into how to treat the room for vocals? I’m assuming the gobo set up is still cheaper but know I should still consider treating the room so I thought I’d ask your opinion before I commit the materials to the panels.

Thank you for all your help this far, I don’t honestly expect a response but I appreciate everything!!

kmetal Wed, 03/30/2022 - 17:50

kmetal wrote: If your planning on resting a panel on the top of them to act as a ceiling, then leave clearance for that. Otherwise they can be as tall as you'd like. How much space at the bottom depends on what sort of wheels your gonna use. RB 40 is the preferred stuff. 60 can work but your limited to a thinner panel and less overall low frequency absorption. Rockwool

The quoting function is a bit wonky right now, but wanted to quote so you know there's response.

The \_/ shape is a good start.

As far as airspace within the panel itself I would tend not to unless your really fine tuning the panel for a known specific problem.  You already have an air gap between panel an wall which increases your LF absorption. Getting into a second airgap gets into multiple impedance "jumps" and adds what is IMHO an unnecessary variable. You can calculate it with the acoustic modelling.com calc if you want.

Instead of airspace I'd use the additional thickness of the panel to fill with fluffy fibreglass, which is a more effective absorber than air. This maximizes the efficiency of the panel, giving the most bang for the buck.

A piece of wood backing, or spaced slats can be effective, and you have the luxury of adding them later with no wasted money or materials. BBC has test data in a paper about "modular wideband absorbers" which is free and will come up on Google.

Unless you know you need it,or there are other reasons to add it initially, then it seems more rational to me, to try out the fully porous units.

Treating the room vs gobos is a pretty difficult question to answer.  If your mixing in the room then treatments for the room make sense.  Realistically having a set of gobos and the full room treatments is what will be best. It's always possible to incorporate the gobos as part of the room treatments later.  It really depends on your priorities.  I would consider room treatments necessary for mixing. So if your doing both mixing and tracking room treatments are probably the best first start, if you can't do gobos and treatments both at once.

kmetal Fri, 04/15/2022 - 17:53

jooshy wrote:

kmetal wrote: If your planning on resting a panel on the top of them to act as a ceiling, then leave clearance for that. Otherwise they can be as tall as you'd like. How much space at the bottom depends on what sort of wheels your gonna use. RB 40 is the preferred stuff. 60 can work but your limited to a thinner panel and less overall low frequency absorption. Rockwool safe n sound is a fine alternative for

Thank you! I’m about to build them, And had some questions!
 

I was wondering what layering you’d suggest? I was going to put the insulation in a frame, cover it and be done - but I see people talking about air gaps IN the gobo as well as the pros and cons of having a piece of wood as a backboard. I was wondering what you might think.
 

And I will play with the set up once they’re assembled but was thinking I’d go with a shape similar to \_/ with the back facing the corner to act as a bass trap. I would be facing out of the cubby. Still need to figure out the ceiling coverage but it seems like that’s the way. 
 

My last thought, I have 3 packs of the 2x4 rb40 with 6 pieces per pack. Do you think I should still make the panels (will be roughly 4x6ft per panel, 3 panels) or should I look more into how to treat the room for vocals? I’m assuming the gobo set up is still cheaper but know I should still consider treating the room so I thought I’d ask your opinion before I commit the materials to the panels.

Thank you for all your help this far, I don’t honestly expect a response but I appreciate everything!!

--

Hey Jooshy not sure how to reply to the message from you in the email so hopefully you will see this.

You wrote-

"Message

Hey, itbs okay if you donbt feel like answering this! Was

just curious what a proper alternative for Safe N Sound 6 inch might be? We

are going to be insulating the room with it but itbs hard to find in roxul

our area is all.

Thank you for your time and no worries if you donbt feel like answering

this one!"

---

Safe n Sound has a GFR of about 10,000 rayls so you would need a product with a similar GFR to make panels of the same thickness as you would with SNS.

Alternatively you could use a product with a HIGHER GFR like say rockwool Rockboard 40, and just use THINNER panels. RB40 is about 15,000 rayls.

Or use a material with a LOWER GFR, like standard fluffy insulation, and make THICKER panels. Standard fluffy is about 5,000 rayls.

You can check this thread for various materials and their GFR.

https://gearspace.c…

And the great Andre Bare has given recommended thicknesses based on GFR

https://gearspace.c…

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