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mulletchuck

Well-known member
Joined
Jan 9, 2010
Messages
1,132
Location
Midwood, Brooklyn, NYC
Howdy.  I was given a 7-pack of Knauf "#6.0 Plain" insulation boards (48" * 24" * 2") (http://www.knaufinsulation.us/products/building_insulation/commercial_building_insulation/insulation_board_with_ecose.aspx) from a friend who had been using it as sound treatment panels when wrapped in Muslin fabric.  I'd like to do the same so i'd have some bass traps in my room and to clear out the reflections a bit.  I know it's not rockwool, but it was given to me for free and was pretty effective in his place for killin' the reflections and bass. 

here are some pics of how my room is laid out.  You can see the massive loft bed that I can't change and where my desk is located.  The closet is to the left of the door (the only wall not drawn in the 3d pics)

screenshot20120102at345.png

screenshot20120102at342.png

screenshot20120102at340.png

imag0202a.jpg

imag0200k.jpg

imag0197pq.jpg


I'm thinking that i could put a single sheet behind the monitors, and then take the remaining 6 and cut them all in half/thirds and have a bunch of smaller panels that I could stagger around the flat parts of the walls. 
 
I have a smallish room, too. All I did was make two panels, about 4' x 2' and hang them on the side walls at ear level to kill the first reflection from my monitors. This helped tremendously. I am thinking of making some sort of bass trap next, although I am pretty happy right now.
 
my room is 14' x 11' x 9ft tall.    I can't really place the panels on the side walls as that's where the window is, and the other side is the closet.  any ideas, folks?  Honestly, i really just want to kill the flutter for tracking.  The loft bed makes it pretty much impossible to be a good mixing room...
 
Hi Chuck,

I would put the material where it can be used to best effect, which would be in front of, behind, and directly above and to the right of your listening position.

The loft bed as you have drawn it will act as a diffuser and this should help to reduce flutter echoes to the LH side of you to some extent.

Absorption in front, above and to the right of you will go a long way towards improving the imaging from your monitors and the material behind you, especially if you can double up on thickness, will help to mitigate standing waves in the low end.

If the panels don't fit then cut them to size.

Whatever you have left I would put wherever you can on the ceiling where it won't be in the way.

That should kill the flutter for tracking and improve your mix space by a huge amount at the same time.  :)

 
awesome.  I'm not sure how to mount on the ceiling.  It's a 'popcorn' ceiling, very rough surface.  I have actually managed to cut my hands up on several occasions when i'm up in the loft just from stretching my hands out if i'm not paying attention and hit the ceiling accidentally.  Any comments for the corners? 



 
It never hurts to beef up the corners if you have the space. You could just put some graduated strips all the way down from ceiling to floor in an approximately triangular cross section.

corners-1.jpg



If you can locate the ceiling joists you can screw battens across the ceiling to use as mounts for the panels. Then build some frames to hold the insulation and screw these to the battens.

To make it easier, get yourself a joist and stud detector and a wire and pipe detector (UK links, sorry) from the hardware store to locate the joists and make sure you don't drill through any lighting cables at the same time.

 
I decided to invest some mental energy into some wood frames and wanted some feedback on this design:

screenshot20120104at125.png


Green part is the insulation wrapped in fabric, white part is the wood frame.  The hope is to create some non-parallel surfaces in addition to MF/HF Absorption.  get some scattering going on.  What say you?  pipe dream?  terrible idea?  great idea?  These are for 2' x 2' sheets of insulation.  I'd be using 1" x 4" size wood for the boxes.
 
Making surfaces non-parallel is more productive than more damping panels.  I've done a lot of theoretical work on speakers in rooms.  Two degrees is enough to make a huge difference.  If you are hanging panels, let them slope some too.

If you are building a studio or purposed listening room, make sure your walls are wonky & the ceiling sloped.

The problem with ANY parallel surfaces is that the flutter echoes need so much damping that your T60 becomes too small (room too dead) for a good listening room.

Also good are open bookshelves (with books).

Try to have Left/Right symmetry for any damping/treatment.
 
i always find "theoretical work" questionable, but this time i'll allow it hahaha.  Lots of people told me not to do wood frames with angled panels but a buddy said to build them for aesthetics since i want to get clients over here.  that ugly NYC blank wall look isn't that attractive.  Obviously, my room is not symmetrical, so L/R symmetry is out of the question.  Tomorrow, i'm hittin' the lumber store!!  I'll let you know how it all goes. 
 
mulletchuck said:
i always find "theoretical work" questionable ...
The hard work was getting the simulations to a stage where they reflected real life.  It's easy to simulate what's happening in crap rooms.  Simulating wonky (good sounding) rooms, was the culmination of nearly a decade's work by 2 separate research bodies.  We used to check each others simulations to see if our alternative methods gave the same answer.

In the 80's, 3 major loudspeaker manufacturers in the UK built special listening rooms at great expense.  All 3 got them wrong cos they used parallel walls.  Don't ask me how I know this.

> Obviously, my room is not symmetrical, so L/R symmetry is out of the question

I did say "try".  You could move the setup nearer the door but I understand if that's not possible.

Have you got a bad flutter echo in one direction?  Which one?

If it's the Window/Closet direction, are things better when the closet is open?  See my comment about open bookshelves (with books).  They are similar to your "boxes" but are dual purpose.

In a room that size, a few cushions / bean bags on the floor are going to be much more effective than anything you can sensible put on the ceiling.

About the only place, I'd put a formal panel would be directly behind the speakers and that would only be cos there is no space for a bookshelf.  Hang it tilted.
 
I have bad flutter all over the place, but i really just want to deaden the room for when i'm shedding sax.  sax is a loud instrument, and in my room there are lots of reflections.  I didn't notice them before, but when I did my sax mic shootout with the CV4 mic, it really showed off how awful my room is. 

i've never closed the closet, so I can't compare lol  But the closet doors are mirrors, so obviously it will be better open.  can't get more reflective than mirrors, can you?

I'll probably put one of the 4x2 panels behind the speakers.  I'm not sure where the smaller 2x2 panels will show up.  i've got 10 of those, tho.. 
 
I'm for the idea of putting a trap across the corner for broadband and bass trapping. For the ceiling corners, you can use picture frame hanging wire. I don't know how heavy that board is, but i have panels made of Owens Corning 703 and they weigh about the same as a picture in a frame.

What you do is put a pair of  picture hanger hooks in the ceiling if you can, or high up the wall. Use the wire near the ends of your panel, hang it up then twist the wire on a stick like a tourniquet to pull it tight. 

Does the same job of bass trapping as putting the thing across a room corner, but doesn't waste any floor space, which seems to be at a premium in your room.

You might also consider a movable panel. You can make a simple stand with a couple of piece of PVC pipe which you can slide into holes in the wood frame you mount your panel/muslin on . Leave it in the corner when you want it out of the way, but put it behind you against the wall to help calm reflections when you're trying to do critical listening. Poor man's version of the freeport panels:
w-nedelle-freeport.jpg
 
I had some very bad flutter echoes on a smallish sized stage. I took a rigid fiberglass panel (1"x2'x3' or so) and held it up in the air and stomped on the floor so I could hear the flutter. Not easy to miss it at all.

Flutter echo is created by parallel surfaces a certain distance from each-other. There were numerous parallel surfaces so I needed to find the worst offenders and treat.

I walked around sticking that panel into corners, up to the ceiling, and all over the place. There was a drastic reduction in flutter at a point towards the front of the stage where the ceiling got about 2ft higher. That is where it helped most.

So, I made three panels (just the 703) and hung them at an angle in those locations across the stage. Just angling them (like 45 degrees or something) was enough to break-up or deflect and attenuate the signal and improve the situation significantly.

I reckon you could use any type of mid-to-largish-sized panel (wood, 703, glass) to at least identify the worst areas and then treat as much as possible. I would use rigid fiberglass to treat if you can swing it. I think a 6-pack of 2'x4' panels is about $70. Add shipping, fabric, mounting, spray-glue (3M 90-24 spray works well). Maybe $200 and you're good to go. 703 is rigid enough that you don't need wood frames for wall panels. Maybe some fabric-covered drywall corner-bead-trim to square up the edges nice and sharp if you like it that way.

Cheers,
jb
 
just to update, i got all the wood cut, and just need to buy hooks to mount these guys on the wall.  I have two 4x2 panels, and 10 2x2 panels.  So, i should be able to add some non-parallel surfaces depending on how I hang everything.  I framed them with the wood on the outside, which looks much nicer. 

imag0204bk.jpg


I'm thinking of checking with all of my friends to see if they know any artists who might be interested in painting these guys, since there is a lot of blank white muslin fabric being used...
 
mulletchuck said:
just to update, i got all the wood cut, and just need to buy hooks to mount these guys on the wall.  I have two 4x2 panels, and 10 2x2 panels.  So, i should be able to add some non-parallel surfaces depending on how I hang everything.  I framed them with the wood on the outside, which looks much nicer. 

I'm thinking of checking with all of my friends to see if they know any artists who might be interested in painting these guys, since there is a lot of blank white muslin fabric being used...
Using the insulation board panels as pin boards will not reduce their efficiency as acoustic treatment.  In fact if you use it to mount a hat collection, they will be even more efficient cos the extra diffusiveness.
 
could some of ya check this little placement clip and tell me what your thoughts are?  I've got 10 of those sized panels to place in here, so i have lots of options, in addition to the pair of 4x2s

http://www.twitvid.com/R8ZXH
 
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