thikcness of wall panels
Old 25th March 2013
  #1
Gear addict
 

Thread Starter
thikcness of wall panels

need some advice here as i am a bit in a confused state.. this is the situation:

1) i have a 12.5 x 15.5 ft mixing room with 11 ft ceilings.

2) it currently has 4 ceiling clouds @ 12 degree angles. each is 2ftx8ft and 1inch thick 703 with guileford of maine fabric.

3) all the corners (vertical and ceiling horizontal) are trapped with 6inch 703 2ftx4ft panels with a 4inch thick smaller nested panel behind it.

4) there used to be a skylight about 4x4 and 4 foot deep cavity. it was completely stuffed with insulation (fiberglass, alternating roxul and some other fiberglass panel boards hung with air spaced between) so it's a big bass trap on the ceiling.

5) the entire rear wall has spaced out RPG qrd diffusors


i am in the process of treating the side walls and the front wall. the builder i am working with insists on placing 6-8ft tall x 2ft wide panels to cover most of the front wall and 5 on each side.

i'm fine with the layout however my only concern is he insists on usign a 1inch combination of 2/3 703 and 1/3 705..

i voiced my concern that the 1 inch might be too thin but he insists that they will be fine and with all the trapping i have 2 or 4 inch will be too much and the 1 inch will get the job done fine. he also says that since the framing is 2 inch thick there is approx 1 inch space between wall and the 1 inch fiberglass and that is better than having the panels flush on the wall.

so for wall panels (front and side walls) any one care to chime in on the 1inch vs 2/4 inch debate?
Old 25th March 2013
  #2
Lives for gear
 
avare's Avatar
 

There is no debate. The minumum recommended is 4" thick and several experts strongly recommend 8" deep overall as a minimum. Not directly applicable in your case, to expand on the 8" for other readers, at that depth 4" of 703 and a 4" gap is an optimum combination, as is 8" filled of Safe N Sound. The latter is a fraction of the cost for the material, but requires a supporting frame. IOW no option of just stacking in a corner or against a wall.

Andre
Quote
2
Old 25th March 2013
  #3
Gear Guru
 
Glenn Kuras's Avatar
 

1" just is not thick enough. As avare said use 4" if at all possible. If anything go with 2" with a 2 to 4" gap.
Old 25th March 2013
  #4
Lives for gear
 
Jens Eklund's Avatar
 

Quote:
Originally Posted by avare View Post
There is no debate. The minumum recommended is 4" thick and several experts strongly recommend 8" deep overall as a minimum.
+1
Old 25th March 2013
  #5
Gear addict
 

Thread Starter
Quote:
Originally Posted by Glenn Kuras View Post
1" just is not thick enough. As avare said use 4" if at all possible. If anything go with 2" with a 2 to 4" gap.
even with all the other trapping that is in the room?

his explanation is that there is so much trapping already and i don't want to kill the room and address the mid-range and higher frequencies.

there are like fourteen 8-inch bass traps in all the horizontal and ceiling-wall corners of the room as well as an enormous trap in the skylight.
Old 25th March 2013
  #6
Lives for gear
1" just won't get it done in those first reflection zones.
Old 25th March 2013
  #7
Lives for gear
 
avare's Avatar
 

Quote:
Originally Posted by aramism View Post
even with all the other trapping that is in the room?

his explanation is that there is so much trapping already and i don't want to kill the room and address the mid-range and higher frequencies.

there are like fourteen 8-inch bass traps in all the horizontal and ceiling-wall corners of the room as well as an enormous trap in the skylight.
Perhaps you missed it; from post #2 in this thread:

Quote:
The minumum recommended is 4" thick and several experts strongly recommend 8" deep overall as a minimum.
Minimally,
Andre
Old 25th March 2013
  #8
Lives for gear
 
Jens Eklund's Avatar
 

Old 25th March 2013
  #9
Gear addict
 

Thread Starter
Quote:
Originally Posted by avare View Post
Perhaps you missed it; from post #2 in this thread:



Minimally,
Andre

as glenn pointed out i may be able to swing 2inch fiberglass with 2inch spacing behind it.

the room is pretty small and 4inch panel + 4inch space is almost taking a foot off each side.

how about 4inch panel + 2inch air space???


also, what do you guys think about the 2/3 of each panel 703 1/3 705?
Old 25th March 2013
  #10
Lives for gear
 
Jens Eklund's Avatar
 

Quote:
Originally Posted by aramism View Post
how about 4inch panel + 2inch air space???


Quote:
Originally Posted by aramism View Post
also, what do you guys think about the 2/3 of each panel 703 1/3 705?
The flow resistivity of 703 is already fairly high so you don´t want to go higher than that, especially if thicker panels.
Old 25th March 2013
  #11
Lives for gear
 
jim1961's Avatar
 

Quote:
Originally Posted by avare View Post
There is no debate. The minumum recommended is 4" thick and several experts strongly recommend 8" deep overall as a minimum. Not directly applicable in your case, to expand on the 8" for other readers, at that depth 4" of 703 and a 4" gap is an optimum combination, as is 8" filled of Safe N Sound. The latter is a fraction of the cost for the material, but requires a supporting frame. IOW no option of just stacking in a corner or against a wall.

Andre
10-12" or thicker of pink fluffy works excellent as well
Old 26th March 2013
  #12
Gear Guru
 
Glenn Kuras's Avatar
 

Quote:
Originally Posted by aramism View Post
as glenn pointed out i may be able to swing 2inch fiberglass with 2inch spacing behind it.

the room is pretty small and 4inch panel + 4inch space is almost taking a foot off each side.

how about 4inch panel + 2inch air space???


also, what do you guys think about the 2/3 of each panel 703 1/3 705?
Have not seen testing of mixing the 2 together. I would just stick with one. 703 is around half the price as 705 so you get twice as much which means you have twice as much treat, which will beat half as much 705 all day long and twice on SUNDAY!
Quote
1
Old 26th March 2013
  #13
Gear addict
 

Thread Starter
Quote:
Originally Posted by Glenn Kuras View Post
Have not seen testing of mixing the 2 together. I would just stick with one. 703 is around half the price as 705 so you get twice as much which means you have twice as much treat, which will beat half as much 705 all day long and twice on SUNDAY!
well i don't think it's about the savings of it. it was explained as it helps having another material in there to break up the "monotony" of having 703 everywhere else.
Old 26th March 2013
  #14
Lives for gear
 
avare's Avatar
 

Quote:
Originally Posted by aramism View Post
well i don't think it's about the savings of it. it was explained as it helps having another material in there to break up the "monotony" of having 703 everywhere else.
That makes no sense at all. You have the professional recommendations.

Andre
Old 27th March 2013
  #15
Gear addict
 

Thread Starter
ok so i'm going to be finishing this myself instead of using the builder guy.

i am thinking front walls 2x8 panels (5 of them) will cover nearly all of the front wall. i will make them 4inches flush against the wall. i can't really come out much more for space usage there. MAAAAYBE if it will make a big enough difference i can put 2inch air behind it.

on the side walls in the front (by the listening positions) there will be three panels all next to each other making up 6 foot of width by 8 ft tall. these will be 4inch thick with 2 air space behind it. I can possible squeeze 4 inches of air behind for a total of 8inches off the wall.

for the mid-rear of room side walls i will go with 2 inch thick with 2 inch air.


thoughts?


the cost is relatively cheap to get the materials it's just a bunch of time spend on it and i'm not a master upholsterer by any means to get them neat looking.

all panels will have oc703 (because the mixture of 705 was shot down by so many people) and guileford of maine fabric
Old 3rd April 2013
  #16
Gear addict
 

Thread Starter
bump...
Old 9th April 2013
  #17
Gear Head
 

Sorry to barge in like this, but I also have a question about this thickness vs airgap thing.
My main problems are at about 70 (null) and 110 Hz (boost). If my wool has the GFR of 8333 P*s/m2, what combination should I use to bite into the problem frequencies?
This calculator says thinnest with biggest airgap is best. Did I miss something? I thought more wool is better, and airgap is just a compromise?

To the OP: I just did a nearly full front wall treatment. Didn´t work because it was not full. Either consentrate on corners or go full wall. So that´s what I´m trying to do, cover the rest of the wall. That is if treating for modes etc. For first reflections smaller area will suffice.

Have You measured the room response? Here´s mine:
Enlarging the triangle 90-160cm
Old 9th April 2013
  #18
Lives for gear
 
avare's Avatar
 

Quote:
Originally Posted by Strand-old-man View Post
This calculator says thinnest with biggest airgap is best. Did I miss something? I thought more wool is better, and airgap is just a compromise?
The calculator is correct. Very little is intuitive in acoustics.

Andre
Old 11th April 2013
  #19
Gear addict
 

Quote:
Originally Posted by Strand-old-man View Post
Sorry to barge in like this, but I also have a question about this thickness vs airgap thing.
My main problems are at about 70 (null) and 110 Hz (boost). If my wool has the GFR of 8333 P*s/m2, what combination should I use to bite into the problem frequencies?
This calculator says thinnest with biggest airgap is best. Did I miss something? I thought more wool is better, and airgap is just a compromise?

To the OP: I just did a nearly full front wall treatment. Didn´t work because it was not full. Either consentrate on corners or go full wall. So that´s what I´m trying to do, cover the rest of the wall. That is if treating for modes etc. For first reflections smaller area will suffice.

Have You measured the room response? Here´s mine:
Enlarging the triangle 90-160cm
That's a nice sequence of measurements !
Looks like you made a big improvement from the gray to the violet.
if you don't mind, could you clarify what the progression is?

Are you straddling the corner with some kind of frame and filling it with loose wool ? ( and then making a bigger frame?)
Or using rigid panels cut to different sizes? (any filling behind them?)

BTW I was also baffled by some of the counter-intuitive results of the calculator. But if you read it on the internet it must be true! But seriously, my gut feeling is that below 100hz these absorbers become so inefficient more has to better. Though the lesson recently learned is that the air gap is very helpful and loose filling behind panels is even more so.
Old 11th April 2013
  #20
Lives for gear
 
avare's Avatar
 

Quote:
Originally Posted by jeff_free69 View Post
BTW I was also baffled by some of the counter-intuitive results of the calculator. But if you read it on the internet it must be true! But seriously, my gut feeling is that below 100hz these absorbers become so inefficient more has to better. Though the lesson recently learned is that the air gap is very helpful and loose filling behind panels is even more so.
Study some more. For starters this thread.

Acoustics is not intuitive. That is what aspirin was invented for.

Andre
Quote
1
Old 12th April 2013
  #21
Gear Head
 

Quote:
Originally Posted by jeff_free69 View Post
That's a nice sequence of measurements !
Looks like you made a big improvement from the gray to the violet.
if you don't mind, could you clarify what the progression is?

Are you straddling the corner with some kind of frame and filling it with loose wool ? ( and then making a bigger frame?)
Or using rigid panels cut to different sizes? (any filling behind them?)

BTW I was also baffled by some of the counter-intuitive results of the calculator. But if you read it on the internet it must be true! But seriously, my gut feeling is that below 100hz these absorbers become so inefficient more has to better. Though the lesson recently learned is that the air gap is very helpful and loose filling behind panels is even more so.
In this I was testing for speaker positions after almost covering the front wall. I had speakers on a "meter bridge" type shelf (self made). In the gray line the speakers were 90cm (3ft) from each other, and every line takes them 10cm wider. I also kept the listening triangle equilateral so that is the distance to the mic as well.
I would not call it improvement.
Will elaborate later.
Old 12th April 2013
  #22
Gear Head
 

Indeed, the gray one was the best though with loudest 110Hz. Moving the speakers apart and LP back I fell into a 70Hz crevasse. Funnily the frequency of the dip rises. Probably a back wall BIR? There is also a mode dip of 70 Hz right there.

So, yes I have a bunch of woolly stuff in here, but it´s not working the way it´s supposed to.
-The front wall has a 264mm wool (8333 Pa*s/m^2)covering (in 5 modules) minus 20cm from the top, where an enboxment (?) for air ducts exists.
-I have two small triangular chunks in front of the modules. Too small (400mm*400mm*550mm) and quite dense wool (22222 Pa*s/m^2).
-There is a cloud 100mm thick of the same denser wool (1800mm*1200mm), suspended 500-600mm from the ceiling.
-Side panels of the same dense wool 1200*800*100mm.
Back wall has a 1800*1200*300mm of mixed wool. (The 22222-one and some random fluffy glass wool) It is centered. I know corners should get the most love, but this has been a long time in the making. I didn´t know better.

All my absorbers are furniture style wooden frame and fabric covering, so I can take them with, when I move.

Since then I have experimented with cardboard tubes. And more wool.
Thank You Andre, for clearing the airgap thing. Next move is swapping the cloud contents for fluffier, and treating the back wall-ceiling corner. There are DVD:s all the way to the ceiling and a ~200mm space behind the top row is vacant at the moment. I´ll make a pillow type for that. Also thinking about testing the 70Hz tube trap in there. A 100Hz one did not do anything. It does however work near the front wall.
Old 12th April 2013
  #23
Lives for gear
 
avare's Avatar
 

Quote:
Originally Posted by Strand-old-man View Post
Thank You Andre, for clearing the airgap thing.
You are welcome.

Andre
Old 18th April 2013
  #24
Gear addict
 

Quote:
Originally Posted by Strand-old-man View Post
In this I was testing for speaker positions after almost covering the front wall. I had speakers on a "meter bridge" type shelf (self made). In the gray line the speakers were 90cm (3ft) from each other, and every line takes them 10cm wider. I also kept the listening triangle equilateral so that is the distance to the mic as well.
I would not call it improvement.
Will elaborate later.
Ok thanks - I totally missed what was getting changed. I thought it was the treatment and not the positions being changed.

And I meant to say that it was the gray that "looked" like a better set of problems to deal with, as opposed to the 20 db hole in the violet around 85.
(which is coincidentally the same issue I've been trying to beat down; I also went through a similar exercise and ended up moving my speakers wider and closer to the front wall. so I should've recognized what "expanding the triangle" meant)
Old 18th April 2013
  #25
Gear addict
 

Quote:
Originally Posted by avare View Post
Study some more. For starters this thread.

Acoustics is not intuitive. That is what aspirin was invented for.

Andre
And black coffee...
Old 19th April 2013
  #26
Gear addict
 

Quote:
Originally Posted by Strand-old-man View Post
... Moving the speakers apart and LP back I fell into a 70Hz crevasse. Funnily the frequency of the dip rises. Probably a back wall BIR? There is also a mode dip of 70 Hz right there.

.... Also thinking about testing the 70Hz tube trap in there. A 100Hz one did not do anything. It does however work near the front wall.
I also noticed a change in the my null center (from 85 to 95) as I moved the speaker / listening position and started adding porous broadband treatment . So I was glad I hadn't jumped right in and tried some kind of tuned treatment. (fortunately for me they're a little more complicated to do, so I was sufficiently discourages at the time
I'd love to hear about your practical results of what and when to incorporate this type of treatment.
Old 14th June 2013
  #27
Gear interested
 

Quote:
Originally Posted by avare View Post
There is no debate. The minumum recommended is 4" thick and several experts strongly recommend 8" deep overall as a minimum. Not directly applicable in your case, to expand on the 8" for other readers, at that depth 4" of 703 and a 4" gap is an optimum combination, as is 8" filled of Safe N Sound. The latter is a fraction of the cost for the material, but requires a supporting frame. IOW no option of just stacking in a corner or against a wall.

Andre
Hi Andre, I am going back a few posts in this thread, but I want to get clarification. When you say "...8" filled of Safe N Sound"...I read that to mean NO air gap--just 8" of SnS against the wall. Correct?
Old 14th June 2013
  #28
Lives for gear
 
avare's Avatar
 

Quote:
Originally Posted by louiein99 View Post
Hi Andre, I am going back a few posts in this thread, but I want to get clarification. When you say "...8" filled of Safe N Sound"...I read that to mean NO air gap--just 8" of SnS against the wall. Correct?
Correct.

Andre
Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Similar Threads
Thread
Thread Starter / Forum
Replies
Dave Derr / Remote Possibilities in Acoustic Music & Location Recording
138
clusterchord / So much gear, so little time!
17
Remoteness / Remote Possibilities in Acoustic Music & Location Recording
62
AlexLakis / So much gear, so little time!
3
amino / So much gear, so little time!
13

Forum Jump
 
Register FAQ Search Today's Posts Mark Forums Read

SEO by vBSEO ©2011, Crawlability, Inc.