Acoustic panels... a photo essay...

tmix · Post by **tmix** » Mon Dec 19, 2005 9:48 pm

Did you use anything to hold the fibreglass in place to keep it from falling toward the front?
I guess the fabric would... I was just thinking if they were ceiling mounted I wonder if I would need to attach the fibreglass inside to keep it from falling into the fabric?

Thanks!

Tom

dbyboth · Post by **dbyboth** » Tue Dec 20, 2005 9:22 am

tmix wrote:Did you use anything to hold the fibreglass in place to keep it from falling toward the front?
I guess the fabric would... I was just thinking if they were ceiling mounted I wonder if I would need to attach the fibreglass inside to keep it from falling into the fabric?

The fiberglass is not that heavy. The fabric on the front easily holds it in place. These panels could very easily be hung horizontally from the ceiling. In fact, you would probably not need the 2x2 blocks as gravity would keep the fiberglass towards the front if they were hanging horizontally from the ceiling.

.db

drewm · Post by **drewm** » Mon Jan 09, 2006 5:30 am

I'm going to be building some panels very similar to these, thanks for the inspiration. I've read elsewhere that you should use faced 703/705 so that you don't deaden the room too much. Can anyone shed some light?
thanks
drew

knightfly · Post by **knightfly** » Mon Jan 09, 2006 6:24 am

Drew, this can work for corner traps where you may want more bass absorption and less mid-high absorption, but the FRK facing should NOT be used for first reflection points like "clouds" and side wall locations - otherwise, you can end up with phase cancellations/comb filtering at the mix position... Steve

drewm · Post by **drewm** » Tue Jan 10, 2006 10:37 am

Makes sense.

thanks
drew

koberlin1 · Post by **koberlin1** » Sat Jan 21, 2006 6:34 am

How have people mounted these panels to the wall? I would like to avoid the toggle bolt idea keeping the wall useable if I ever take them down.

Hanging them like pictures would seem challenging as I have around 30 of these things to hang (2' by 4' panels) and getting them even and solid would seem impossible.

I thought of maybe using "L" type brackets on the insides of the 1" by 4" pine framing but that would mean I would have to put the frame up first, screw in the L brackets, then insert the 703...however I wanted to cover the panels like dbyboth with burlap making this also undoable.

Depot has some hanging alternatives but I want these things to be solid on the wall...not "haninging" so that they could possibly fall off easily...

I will also be "caddy-cornering" a bunch of 2by4 and 2by8 panels which I have no idea on how to attach the wall...

tmix · Post by **tmix** » Mon Jan 23, 2006 10:18 am

My plans are to run a piece of 1X3 wood as baseboard trim(possibly with a routed edge for looks) and one about the top of where the panels will hit, and then mount the panels with "L brackets" to the 1x3s.

Mitch Lowen · Post by **Mitch Lowen** » Thu Feb 09, 2006 2:14 pm

dbyboth wrote:I'm flattered that this post became a sticky. Just to be clear... (maybe I can find a few minutes to make a drawing). The panel shown being constructed in the photos has only one layer of 2" OC 703 with a 2" air gap between it and the wall it's mounted on. (I have hung them like big pictures). This panel is meant be a broadband absorber and I intend to have them hung on the flat walls of my 11' x 11' bedroom studio.

I cannot modify or tear up the bedroom walls as I intend to sell this house and I'm quite sure the new owner will probably want to use the room as a bedroom again so the panels are removable and I'll take them with me and probably incorporate them into my next studio.

The second panel I made the night I made the photos has two layers of 2" OC 705 which is actually about a half an inch thicker than the 2" wood frame. I covered the front with burlap in the same manner but I made three strips of burlap about a foot wide and stapled them across the back to hold the fiberglass in the frames. This is the panel you see in the corner and is intended to work as a broadband bass trap.

I intend to make several more panels. Three of them will be bass traps like the one in the corner but I will use faced 705 for the top layer (facing on the room facing side) Two of these will go in two of the three remaining corners (unfortunately the door into the room is in one of the corners), and the third will bridge the ceiling/wall corner above the wall you see in the photo.

All the rest of the panels will be the single layer 703 type and will be hung on the walls. One horizontally behind the speakers, two vertically on the back wall, one on the left wall and one on the right wall.

The screws I used were "Grip Rite" Trim Head Square Drive screws. Once you use Square drive screws you won't go back to Phillips Head.

I hope that covers it....

.db

It looks GREAT. I am in the process of fixing the acoustic problems in my own room, after getting your post + pics recommended twice (!) I decided to join the forum!

My question:

What do you put at the BACK of the traps. It's wood (MDF?) as frame.. the little wooden blacks for support (?) the thing material for the front.. but what do you use for the BACK?

I'd love to know... I'll be a regular. I'll post a bunch of pics tomorrow - I'd love to get the max result as well. I spent 400 so far and the only 2 things that REALLY worked well: hanging up curtains behind my monitors AND the self-built MDF filled with sand! speaker stands..

Left to do:

sidewalls
backwalls

I just bought a bunch of gear (and was about to buy more) that I probably do not need based on the pics I just saw and what more people have told me.

Mitch Lowen · Post by **Mitch Lowen** » Thu Feb 09, 2006 2:18 pm

Mitch Lowen wrote:
dbyboth wrote:I'm flattered that this post became a sticky. Just to be clear... (maybe I can find a few minutes to make a drawing). The panel shown being constructed in the photos has only one layer of 2" OC 703 with a 2" air gap between it and the wall it's mounted on. (I have hung them like big pictures). This panel is meant be a broadband absorber and I intend to have them hung on the flat walls of my 11' x 11' bedroom studio.

I cannot modify or tear up the bedroom walls as I intend to sell this house and I'm quite sure the new owner will probably want to use the room as a bedroom again so the panels are removable and I'll take them with me and probably incorporate them into my next studio.

The second panel I made the night I made the photos has two layers of 2" OC 705 which is actually about a half an inch thicker than the 2" wood frame. I covered the front with burlap in the same manner but I made three strips of burlap about a foot wide and stapled them across the back to hold the fiberglass in the frames. This is the panel you see in the corner and is intended to work as a broadband bass trap.

I intend to make several more panels. Three of them will be bass traps like the one in the corner but I will use faced 705 for the top layer (facing on the room facing side) Two of these will go in two of the three remaining corners (unfortunately the door into the room is in one of the corners), and the third will bridge the ceiling/wall corner above the wall you see in the photo.

All the rest of the panels will be the single layer 703 type and will be hung on the walls. One horizontally behind the speakers, two vertically on the back wall, one on the left wall and one on the right wall.

The screws I used were "Grip Rite" Trim Head Square Drive screws. Once you use Square drive screws you won't go back to Phillips Head.

I hope that covers it....

.db
It looks GREAT. I am in the process of fixing the acoustic problems in my own room, after getting your post + pics recommended twice (!) I decided to join the forum!

My question:

What do you put at the BACK of the traps. It's wood (MDF?) as frame.. the little wooden blacks for support (?) the thing material for the front.. but what do you use for the BACK?

I'd love to know... I'll be a regular. I'll post a bunch of pics tomorrow - I'd love to get the max result as well. I spent 400 so far and the only 2 things that REALLY worked well: hanging up curtains behind my monitors AND the self-built MDF filled with sand! speaker stands..

Left to do:

sidewalls
backwalls

I just bought a bunch of gear (and was about to buy more) that I probably do not need based on the pics I just saw and what more people have told me.

OK now I see how u did the holding of the fiberglass.. looking pics - not reading. Tired it's 5:18am.. gotta get up at 8am... to work... to pay for these panels

dbyboth · Post by **dbyboth** » Sun Feb 12, 2006 10:59 am

I finally got all the panels made and hung in my little bedroom studio. The difference is obvious and very positive. I may still put a couple of these panels on the ceiling but that's for another day. There are three types of panels in the photo:

4" with two layers of 2" OC705 in the corners
4" with one layer of OC703 spaced 2" off the wall. (most of the vertical panels)
3" with one layer of OC703 spaced about 1: off the wall. (Horizontal panel on side wall, and vertical panel between the doors).

Vertical panels are hung like pictures with picture wire strung through eye hooks. The horizontal panels are just resting on nails nailed in the wall.

Enjoy....db

Slavick · Post by **Slavick** » Tue Feb 14, 2006 12:28 am

dbyboth
thanks for the great essay!!!...it's really make sense...
I wnated to ask to things:
1)what do you think of those:
http://www.johnlsayers.com/HR/index1.htm
As I mentioned you haven't made a corner trap but a kind of wall trap just attached to a corner and also without those wooden slats altering with different gaps nad also you used only one layer of insulation...All I want to know is are your panels as good as those I linked.It's just much easier to make your-way panels instead of those.
2)what was the effect?I mean what kind of monitors do you have and what was the difference in sound when you attached all of your panels to the wall with when you haven't them
thanks...

ViLo · Post by **ViLo** » Wed Feb 15, 2006 2:02 am

Great work! you inspired me to make my own traps, where is SPI Dallas Located?

Thanks

dbyboth · Post by **dbyboth** » Wed Feb 15, 2006 3:50 am

Slavick wrote:dbyboth
thanks for the great essay!!!...it's really make sense...
I wnated to ask to things:
1)what do you think of those:
http://www.johnlsayers.com/HR/index1.htm
As I mentioned you haven't made a corner trap but a kind of wall trap just attached to a corner and also without those wooden slats altering with different gaps nad also you used only one layer of insulation...All I want to know is are your panels as good as those I linked.It's just much easier to make your-way panels instead of those.
2)what was the effect?I mean what kind of monitors do you have and what was the difference in sound when you attached all of your panels to the wall with when you haven't them
thanks...

I can't tell you if my panels are better or worse than the ones shown but they certainly are easier to make! The ones in the corner have 4" thick Owens Corning 705. That stuff is dense and they are pretty heavy. You could, probably pretty easily put another layer and make a 6" panel if you can afford to lose the space in the corner. From everything I have read, for this type of absorber more is better in total mass for low frequency absorbtion.

As far as the effects. The first and most noticable is a dramatic reduction of ambient reverb. The room is fairly dead. With carpeted floors the bulk of the bounce is off of the ceiling and I really would like to add two panels up there as well.

The second, and very noticable effect was the imaging. I have Mackie Hr824's and a 10" JBL sub that is driven directly by an Alesis studio amp and crossed over with an Alesis EQ.

I bought the Mackies after listening to a pair in another studio. I can tell you when I first put them in my room, they sounded good but I wasn't as blown away as I was listening to them in the other studio. After installing the panels, I can sit in the sweet spot and pick out every instrument where it's panned to and visualize sounds coming from between the speakers. Now I'm blown away, especially listening to something like Steely Dan's Aja, or a great Alison Krauss mix.

The next, more subjective effect is translation. I was having a hell of a time making mixes that sounded good elsewhere, especially in the car. Upper mids and bass were especially troublesome. It was like delayed feedback mixing. It would sound great in the studio but crappy in the car. I'd have to make notes of what to change, then cut another disk and listen to it all over agian in the car. I just couldn't pick out the bad spots. Since the panels were installed, I can really guage the bass levels. The mixes.

I did some Room EQ measurements (very unscientific) using pink noise and the PAZ freq plug in. There's not a lot of resoution but there was some measureable flattening to the curve after all the panels were installed. With the sub, I get a pretty good curve down to about 30hz measuring in a corner.

Slavick · Post by **Slavick** » Wed Feb 15, 2006 4:08 pm

Thanks dbyboth...today I'm going to put my hands on cunstruction of these panels.I've decided to make "An easier one" type...Besides I see many people on this forum a kind of "lazy" and building the panels like this...so I'm not going to stand out of the croud!

Also my dimensions are very tight-something about 2.25(m) in height,2.60(m) in width and 2.90 (m) in lenght...so I really don't want to loose extra space in my control room.
Thanks one more time for the great essay,as I've already wrote: it really made sense for me how to do these panels.
P.S.: I hope I will be also blown away but from my Behringers...

dbyboth · Post by **dbyboth** » Wed Feb 15, 2006 8:40 pm

ViLo wrote:Great work! you inspired me to make my own traps, where is SPI Dallas Located?

Thanks

S P I Specialty Products & Insulation
(972) 620-1009
11232 Leo LN
Dallas, TX 75229

It's near the intersection of Royal Lane & Harry Hines. The guys working there are very friendly and encouraged me to send my audio friends!

...db