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Basement 'control room' project

Posted: Thu Jul 16, 2015 12:03 am
by kemi
Hello,

Like most of the newcomers here, I have been lurking around for a while. It helped me decide a couple of things that are really important and has raised even more questions! Next to this forum I have read Rod Gervais excellent book. Again: lots of questions answered yet many new questions popped up. This is the reason why I'm willing to plunge and hopefully be able to make those final planning and design decisions.

At this moment I am stripping the basement bare (lots of cupboards, workbench, ...). I just need to put the washer, dryer and freezer in the adjacent storage room and a plumber needs to come over to remove a water pump that's broken. Maybe he will need to fit in some pipes to be able to put the washing machine elsewhere but that's a question I hope will get resolved with your help!

I live next to a busy road, which means I get about 45dBC at my (planned) listening position and just above there's the living room. I produce bass heavy music (techno, drone, industrial) so the living room gets a lot of low frequencies to handle. Especially the chimney and walls vibrate. I hope to compensate this by decoupling walls, ceiling and perhaps the floor of the basement.
I have no neighbors to really deal with. On one side there's a corridor and garage in between the studio and the neighboring wall and on no neighbor on the other side. Back and front aren't an issue either. Upstairs and traffic noise is the main concern.

This project should be considered as a control room. I barely use a mic and it's not in the same manner as, for instance, a pop or rock recording. I want to work towards a room in which I can produce and mix everything (perhaps even tempt to master).

I have doodled something in SketchUp. First experience so go gentle on me.

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On the left the vent. At present, this gives out onto a grid and the outside world. I have yet to figure out how I will let air circulate but I think I will remove the grid and put a silencer on top.

You can see that the stud wall next to the vent is not a double wall at the moment. I've read that people use a bay window as a bass kick the door open just to put or take away, but maybe this is a myth? Would be even cheaper if I could leave that door. But what about flanking?

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In the studio you can see that the chimney wall is still part of the room and I did not put a double wall in front of it. But perhaps this is not a good idea as I keep the sound transmission in the living room in mind? Only to lose 20cm here would give me a space of 3m10 wide. Too narrow, right?

The fact that I put a 'washing room' behind the studio is due to room ratios. If I use the entire room, I end up to close to 2 cubes stuck together. Something to avoid, I have read. Or would you advice to forget about that and just use the entire space at hand? I can always place the washing machine in the storage room...

I do foresee problems concerning the doors. As in, there is one too many. I would rather work purely symmetrical (control room design).

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Currently, there is a tile floor in the basement. Is it a good idea (cf. transmission of bass through construction) to impose a floor here consisting of acoustic OSB plates with laminate? If so, how do I build my wall? Does it need to rest on the tile floor or directly on the OSB plates (with acoustic stripping in between wall and floor in both cases)?

Re: Basement 'control room' project

Posted: Sat Jul 18, 2015 2:38 am
by kemi
I have put in more effort and detail in the sketch.

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First attempt at putting in a vent with a baffle box outside.

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The rear wall (from the listening position) is now double stud. But I'm not sure if it would be better to use the entire space. I could fit the freeze, washer and dryer in the small storage room but I'm not sure about the ratios. With this design I get 2,3m x 6m x 3,3m (with usage of the entire space that becomes 2,3m x 8m x 3,3m)

Re: Basement 'control room' project

Posted: Sun Aug 02, 2015 11:07 am
by Soundman2020
Hi Kemi, and welcome! :)
I hope to compensate this by decoupling walls, ceiling and perhaps the floor of the basement.
You don't need to do anything to the floor (assuming it is concrete?), but yes, the walls and ceiling certainly will need to be decoupled. Your best bet would be to follow the "room in a room" concept. Basically, that means that you need to seal the existing walls and ceiling to make them air-tight, and you might need to add more mass to them, in order to get good isolation. That is your "outer leaf". Then you build a new frame inside that sealed outer-leaf (four walls plus ceiling), and put drywall on just one side of that frame, also sealed air-tight. And that's about it!
I want to work towards a room in which I can produce and mix everything (perhaps even tempt to master).
OK, so to summarize, this is basically a control room for recording and producing non-acoustic instruments, mixing, and mastering. Is that about right? If so, you will need to change the geometry that you are using right now, for the speakers and the mix position. You have your speakers right in the corners and angled at 45°. That is not correct: speakers should never go in the corners: they need to be much further into the room than that. They should set up at a distance from the side walls that is equivalent to about 25% to 30% of the room width, and they should be angled at about 30°. The mix position should be about 35% to 40% of the room length away from the front wall. That's the correct basic layout.

You are showing that you plan to flush-mount or "soffit-mount" your speakers, which is a very good idea. However, you should look at some examples on the forum of how to design and build the soffits correctly.
I have doodled something in SketchUp. First experience so go gentle on me.
:) :thu: Please post your photos directly on the forum, instead of on an external hosting server. Sometimes those servers change or disappear, so the photos are then lost, and other people following your thread in the future won't be able to see what we are talking about. That's why we ask that all photos be posted directly to the forum.

Also, please post your actual SketchUp model on the forum so we can download it and look at it ourselves, and maybe play around with it. If it is too big to put on the forum, then it is OK to put that on an external file-sharing service, such as DropBox, and post the link here.
The rear wall (from the listening position) is now double stud. But I'm not sure if it would be better to use the entire space. I could fit the freeze, washer and dryer in the small storage room but I'm not sure about the ratios. With this design I get 2,3m x 6m x 3,3m (with usage of the entire space that becomes 2,3m x 8m x 3,3m)
Use one of these Room Ratio calculators to figure out the best dimensions for your room:
http://www.bobgolds.com/Mode/RoomModes.htm

http://amroc.andymel.eu/

Both of those are very good, and will help you to decide how best to build your room.


- Stuart -

Re: Basement 'control room' project

Posted: Wed Aug 05, 2015 2:38 am
by kemi
Thank you very much, Stuart. It was worth the wait as I was unaware of the fact you shouldn't put the speaker right up in the corners. I will change my design according to your percentages and upload it directly to the forum along with some pictures.

I have been kitting up and filling some cracks and cables that run through the walls and ceiling with expansion foam. Anyway, I'll be back in a couple of days.

Big thank you already!

Re: Basement 'control room' project

Posted: Fri Aug 07, 2015 11:50 pm
by kemi
I have altered and added quite a lot in the design.

1. The direction the listening position was in has turned 180°.


2. I have put in an HVAC intake and outlet. I think I have even used your designs for the baffle boxes in SketchUp Stuart. Important to know is that the outlet goes up through the adjacent space and garage through to the conservatory.


3. As I'm using the entire space now, I have opted to get the metal stud right unto the sides of the chimney and sticking some neoprene in between. I would stick the drywall against the chimney with some Greenglue. But maybe this isn't a good idea and I should put the metal stud in front of the chimney? I'm not able to put in a gap worthy that name though. My room would have a width that is not satisfactory.



I have checked the room mode calculators and these new measurements are pretty nice. They give a nice Bonello curve with the following information:

Computed Information:
Room Dimensions: Length=7.97 m, Width=3.39 m, Height=2.18 m
Room Ratio: 1 : 1.55 : 3.64
R. Walker BBC 1996:
- 1.1w / h < l / h < ((4.5w / h) - 4): Fail
- l < 3h & w < 3h: Fail
- no integer multiple within 5%: Pass
Nearest Known Ratio:
- "15) Golden rule ratio: 1968" 1 : 1.236 : 3.236
RT60 (IEC/AEC N 12-A standard): 268 ms
- ±50ms from 200Hz to 3.5kHz = 218 to 318ms
- ±100ms above 3.5kHz = 168 to 368ms
- <+300ms at 63hz = 568ms
- 300<RT60<600ms
RT60 (ITU/EBU Control Room Recommended): 209 ms
- ±50ms from 200Hz to 4kHz = 159 to 259ms
- <+300ms at 63hz = 509ms
- 200<RT60<400ms
Absorbtion to achieve ITU RT60: 488 sabins
Volume: 59 m^3
Surface Area Total: 102 m^2
Surface Area Floor: 27 m^2
Surface Area Ceiling+Floor: 54 m^2
Surface Area Front Wall: 7 m^2
Surface Area Front and Rear Wall: 14 m^2
Surface Area Left Wall: 17 m^2
Surface Area Left and Right Wall: 34 m^2
Surface Area 4 Walls: 48 m^2
Surface Area 4 Walls + floor: 75 m^2
(sabins - front wall - carpet) / Left+Right+Rear wall: 27 %
(sabins - front wall) / Left+Right+Rear wall: 93 %
Schroeder Fc: 112hz
Frequency Regions:
- No modal boost: 1hz to 21hz
- Room Modes dominate: 21hz to 112hz
- Diffraction and Diffusion dominate: 112hz to 448hz
- Specular reflections and ray accoustics prevail: 448hz to 20000hz
Count (21.6-200hz) : Axials=14, Tangentials=51, Obliques=54
Count (21.6-100hz) : Axials=6, Tangentials=6, Obliques=1
Critical Distance (direct = reverberant field): 4.10m

4. I have changed the soffits according to your percentages. Also the floating floor attempt is gone and there is concrete underneath the tiles.




Here is the complete SketchUp file: https://www.dropbox.com/s/d75tgdhovo271 ... i.skp?dl=0

Pictures to follow over the weekend. Need to clean up and fill some more cracks first.