Time to add some treatment

[chordaroy]

Hi
Thanks for the opportunity to ask some basic questions on acoustic room treatment.
I've been collecting recording equipment for a will and now it's time to treat the control room before I invest in some serious monitors. I've been using headphones and my stereo til now.
The room is very small. 2.8 m by 2.9 by 2.4 ceiling. That's 9'6" x 9'10" x 7'11"ceiling. Walls are gyprock (plasterboard?)
There is a corner doorway and windows on one end of the room. See attached drawing.
First question what effect will having the doors and windows open have on the room acoustics? Do I have to have them closed to treat the room effectively? I live in a quiet part of the world so extraneous noise is not an issue. THough the neighbours might not like late night mixing!
Secondly- floors are timber. Is there a preferred floor covering?
Third- I have a Behringer ECM8000 and have seen some room analysis software (free). Do I have an attempt to sound proof the room before I try any analysis? From what I've read base traps should be high on the shopping list.
My set up is orientated perpendicular to the drawing at this stage but have thought the desk might be better at that end of the room because I've read the rear wall is not as critical to room acoustics and the windows will be less of a problem behind them. What do you think?

Any advice would be great.

[stainless]

welcome chordaroy!

standard disclaimer: I am not an expert on room acoustics or acoustic design, however I've made progress through trial and error (lots of errors), so hopefully at least one thing I say will be helpful

running your room dimensions through Ethan Winers Room Mode calc-  58 Hz, ~280-290 Hz,  356 Hz, and low 500 Hz will be the ones where standing waves become a concern, with 356 being perhaps the worse-  furniture, windows doors will have an impact (so yes, doors/windows open will changes things, and I would think doors would pose a bigger issue being a larger reflective surface

the corners behind the monitors would typically be a prime spot for bass traps, so the windows put a hitch in having a ceiling to floor

"I" would use the analyzing software to give you a starting point of the room, so you have some means of judging if what you're doing is helping or not.

I'd add bass traps first in the corners above/below the window corners, and a couple on the long wall ceiling "corner"- maybe 2 on the wall with no door and one on the one with thbi-fold- and I would not place them across from each other, but staggered)  If space allows above the book case for as much of the wall as you can

Hardwood floors are nice, a heavy area rug would add some dampening, but I'd probably concentrate on hanging "clouds" randomly from the ceiling, some up against the ceiling and others with a space behind them.  A cloud above the mixer, and some type of diffuser/baffle between the 2 windows

many give a general rule of thumb to not have opposite/opposing surfaces bare/reflective, however I see many studios that have the wall panels (diffusers) placed evenly

the wall construction and ceiling itself will play into the environment- how heavily they're insulated, how thick the walls are, how thick the drywall, etc....  so ultimately your looking for the best treatment, despite the fact that it will in essence be a compromise

use the analyzing software  with each additional treatment you add- I'd suggest locating the sensor in multiple locations (every time) and make sure it's as close to the same as you can-  ESPECIALLY where your ears will be (you want the best seat in the house right?)

keep us posted on how this proceeds

[RawDepth]

+1 to everything Stainless said.

Your primary concern is sound from the monitors reflecting from walls back to you. The less reflections you hear, the clearer you will hear the real mix.

[chordaroy]

Thank you for the warm welcome and quick and informative replies Stainless and RawDepth. I liked the home page welcome and open feel of this site.

The windows behind the speakers being potentially problematic, would a different orientation be better for a start? It would mean the bookshelf would be on the side wall where the door is. The desk could be moved to the wall where the bookshelf is now or to the wall across from the tri-fold door.

There are vertical blinds on those windows at the moment, I could build a removable treatment for them but would need to be sure it was going to make a substantial improvement. I did see on one of Ethan's videos that he has speakers in his room with windows behind them. He says something like the speakers throw the sound forward.......  however I realise sound does come out the back of a speaker. I don't know what distance to the window and what curtain/treatment on the window Ethan has.

Next thought is it ok to have the doors and windows open and analyse with those open and treat from there?

Once again thankyou for the advice.

Chord

[stainless]

with the shape of your room and the placement of doors- your placement now may be the best, however you could use the long wall, In my control room I have a similar problem with doors and so for me, the room is wider than it is deep.  I have had to add quite a lot of traps, baffles/clouds/diffusers

basically hard to say without being in the room and dealing with it first hand- the blinds probably will offer very little in the way of diffusion or absorption. It may be enough to place traps in the corners above and below where the windows com into the corner, a trap above on the ceiling and a diffuser directly in front of you. The rest of the room will still need addressing

as to whether to leave doors open or closed- use your ears, What sounds better to you? This will be the space you mix in, regardless of what you do to the room, you will have to "learn" the room"

I'd start by deciding upon a couple of commercial CD's that has material you are very familiar with AND really like the sound. Use these as your references for what changes in the room make it sound better/worse, or can't tell a difference

if this was easy we'd all have homes that sounded like the New York Metropolitan! 

[chordaroy]

Yes it is a journey we travel. Haven't had the chance to test the room before treatment yet. I've been busy pricing foam v DIY insulation style. I'm leaning towards insulation. We have a product in Australia called Tontine Acoustsorb 3 which is 48kg/m^3 comes in 2400 mm x 1200 mm and 50mm thick. It has close to the same specs as other sound proofing insulation. http://www.spec-net.com.au/company/tontine/acoustic/acous6.htm

I was thinking I would cut it into triangles and fit in the ceiling/wall space around the room using small timber battons to hold it up and material light enough to allow sound through to cover them. Same triangle idea for the back corner. Side wall reflection points would be treated as well with same product put into frames, doubled or tripled 100 -150mm and hung off the wall some. The ceiling similar to the walls above mixing point. It looks like costing me a third of the foam option. I'm quietly confident I might be able to make it look acceptable to my partner as well.

Also I was thinking of bending a plywood sheet as a diffusor behind the desk between the windows using the window architraves as supports and frame. I've seen similar on Ethan's web page. The architrave/frame would need to be reinforced to handle the plywood bending pressure. What sort of distance from the wall should the central point of the arch in the sheet be?

What do you guys think??

Chord

[stainless]

yep- that "sounds" like the same material

see http://www.recordingproject.com/bbs/viewtopic.php?t=30783

as to the bent plywood/diffuser  it seems like that might actually "concentrate" some of the sound projected back (like a satellite dish?) I'd be more inclined to try the curved surface with random spaced slats (like a modified Heimholtz resonator of sorts) with insulation behind and some "dead space"

this is all brain-strumming and might not be of much use at all

but the mini bass traps work well

and find an old electric carving knife for cutting the rigid fiberglass panels down to size

[chordaroy]

Thanks for the link to the other forum. Your photos help to enlighten. Also others you posted. Cool room Stainless.

Could you please answer a few questions?
What material did you use to finish the ceiling traps on the ends?
You mentioned there something about tubes supporting the traps so they didn't squash up or something....... didn't quite get that.
The million dollar question.... happy with the result?

Have to go, thanks for the help.

Chord

[stainless]

Thanks!

on the exposed ends of the traps I cut a piece of peg-board the right size/shape and covered with fabric- I used 4d nails into the wooden/triangular "stops"

If I understand the question, the "tubes" were plastic "bushings" from the hardware store with a washer in between the bushing and the panel so I could maintain a 1" or 2" air space behind so there was a 'stop' of sorts in case someone push or leaned on it

and yes, it made a tremendous difference in the rooms- I wish I had done it much sooner-
It took me severa weekends and evenings to get done, and I did put a few extra homes in my wall moving some of the panels if I found it didn't make much of a before after difference.... just like mic placement... moving the panels a few inches made a difference the room correction would pick up

[chordaroy]

Thanks

Having some language differences here. I think peg board is what we call masonite here with small holes drilled into it regularly spaced. The air space was behind the rectangle panels to keep them off the wall not behind the triangle corner bass traps. Bushings...... being a plastic screw???

The faces of your treatments look really professional. Did you cover the front of the traps with a thinner panel covered in material and screwed to the timber supports?

Our sheets come in 1200 x 2400 x 50 mm. That's 47.2" x 94.5" x 2". If I cut these sheets in half and make triangles the hypotenuse (long side) will be 33" this seems awfully large for my space. If I go down half again I get 16" hypotenuse face. Will this be a larger enough face to do the job do you think? I think I read some posts of yours that asked similar question with no reply. Ideas? Cutting this way means no waste. The acoustisorb 3 is only $5 a sheet. Comes in packs of three and costs the same to frieght it to my place. Currently looking at 12 sheets. So I guess its not that expensive to cut it in less symmetrical cuts and have waste. I could use the waste in other traps/reflection points but it wouldn't be as easy to mount as a whole piece. The leonard traps are one foot I think by two foot high which gives a hypotenuse face of just under 17". 

Got to go. Chat later. Thanks for your thoughts.

Chord

[stainless]

pegboard = masonite with evenly space holes

airspace is behind the diffuser panels, not the traps

the bushings are http://www.plasticbushingdesign.com/ - the non flanged type. You could also drill a hole in a block of wood- they are basically spacers so all the spots that I screw the panels to the wall/ceiling are evenly spaced and not "taddy-wompus" 

our sheets come in 24" x 48" - Have traps that are "mini" 6" x 6" on the base/height) as well as 8" x 8", 12" x 12" and 24" x 12". I chose these dimensions becuase they were equally divisable into the 24" x 48" panel to eliminate waste (which I had very very little)

The objective behind my mad scientist approach was to have a minimum depth of 4" directly into the corner, which the 6x6 does and all others exceed.  I cut 1" material for the front and covered  with fabric. The edges against the angled "intercept" was cut at a 45° which took me a couple of trials befor I made a jig to use as a guide for the electric carving knife.  because of the way i cut the wood "rails" this also gives me a 1" dead air space behind the front cover panel and the trap