[HT cOz]

Dave where are the best places to use these products?  I'm building a room right now and am wondering if I could incorporate these into the plan.  Right now I have plans for a lot of obsorbtion but no diffraction.  Check out my gallery for pics of the build.

My speakers which I will build once the house is finished are going to be AV3-Neos (Pre Neo3 speaker) accross the front.  Towers and Center. 

Any ideas you guys have are appreciated.

[poseidonsvoice]

Dave,

Do you have any pictures of these diffusers? I looked on the website to no avail.

HT cOz,

Typically diffusers are placed on the side walls, but more towards the rear 1/3rd of the room and the rear wall itself. For dipole speakers you can place them on the front wall behind the speakers that is. Some also use diffusors on the ceiling over the audience/listeners.

Best,
Anand.

[dBe]

Dave where are the best places to use these products?  I'm building a room right now and am wondering if I could incorporate these into the plan.  Right now I have plans for a lot of obsorbtion but no diffraction.  Check out my gallery for pics of the build.

My speakers which I will build once the house is finished are going to be AV3-Neos (Pre Neo3 speaker) accross the front.  Towers and Center. 

Any ideas you guys have are appreciated.

Thanks for the questions you two.  Let me give you a little background and then some answers.

The background is basically this:  I am having a struggle getting these items marketed to a point of satisfaction.  It has been basic logistical problems that are the pain in my butt.  They are not like my other products where I control all aspects of the procedure.  I am having to rely upon others for 70% of the process and I have found this 70% to be a royal PITA.  I am finally going to have some quality pictures taken (hopefully next week) to post on the website.  At that time there will be a LOT more info available.  This ispredicated on the pictures actually happening next week... I've been trying to make this happen for a couple of months.

As to layout, Anand is correct: the most effective utilization of diffusion is to the sides and behind the listening position.  In 2 channel systems, I usually prefer a single narrow column of diffusion directly in front of the listening position, centered between some sbsorption in the first reflection points.  As a point of use, generally I use absorption in the primary (first order or direct) reflection points and diffusion in the second order reflection points.

If you want to shoot me a PM, we can address your specific application off the forum, or if you don't mind the scrutiny, post the floorplan of the room and we'll go through placement plans as well as some general room acoustics.

It's all good.

Dave

[HT cOz]

I can handle the scrutiny and that way others can learn too.  Like many I'm pretty lucky to have any dedicated space so it's not the biggest room in the world.  I have a thread in the accoustic circle with more detail but here is the basics.




I am building a number of boxes in the room that are 6 inches deep.  The first reflection points are covered at the front, side, and ceiling.  I also have some smaller boxes on the rear wall.  These will be dry walled around.

Here is a pic of front and side boxes.



Thanks,
Robert

[dBe]

I can handle the scrutiny and that way others can learn too.  Like many I'm pretty lucky to have any dedicated space so it's not the biggest room in the world.  I have a thread in the accoustic circle with more detail but here is the basics.




I am building a number of boxes in the room that are 6 inches deep.  The first reflection points are covered at the front, side, and ceiling.  I also have some smaller boxes on the rear wall.  These will be dry walled around.

Here is a pic of front and side boxes.



Thanks,
Robert

Been a busy weekend, sorry for the delay.

First, a couple of questions that I "think" I know the answer to, but I want to know for sure.

Which end of the room does the screen go on?

What type of wall insulation are you going to use and what is the interior wall finish going to be?  Drywall?  How many layers of what thickness?

Thanks,

Dave

[HT cOz]

Been a busy weekend, sorry for the delay.

First, a couple of questions that I "think" I know the answer to, but I want to know for sure.

Which end of the room does the screen go on?

What type of wall insulation are you going to use and what is the interior wall finish going to be?  Drywall?  How many layers of what thickness?

Thanks,

Dave

The screen is going on the large square end.  We will be using blown cellulose insulation with 1 layer of 3/4" drywall.  The exterior wall construction is brick -> air space -> 3/4" rigid foam -> Tyvek drain wrap -> 1/2" OSB -> 2" x 4" with blow cellulose -> 3/4" drywall -> latex paint

[dBe]

The screen is going on the large square end.  We will be using blown cellulose insulation with 1 layer of 3/4" drywall.  The exterior wall construction is brick -> air space -> 3/4" rigid foam -> Tyvek drain wrap -> 1/2" OSB -> 2" x 4" with blow cellulose -> 3/4" drywall -> latex paint

There is always a couple of ways to skin a cat.  First some data:

1   0   0   45.50   A
0   1   0   56.97   A
0   0   1   62.78   A
1   1   0   72.92   T
1   0   1   77.53   T
0   1   1   84.78   T
2   0   0   91.01   A
1   1   1   96.22   O
2   1   0   107.37   T
2   0   1   110.56   T
0   2   0   113.95   A
1   2   0   122.70   T
2   1   1   124.38   O
0   0   2   125.56   A
0   2   1   130.10   T
1   0   2   133.55   T
3   0   0   136.51   A
1   2   1   137.83   O
0   1   2   137.88   T
1   1   2   145.19   O
2   2   0   145.83   T
3   1   0   147.92   T
3   0   1   150.25   T
2   0   2   155.07   T
2   2   1   158.77   O
3   1   1   160.69   O

Here is a modal plot in the bass frequencies.  As you can see from this, you will have serious room gain below the mid 60's.  I would advise an easy hand on the subwoofer gain control.     At least you won't need a ton of power to make the room shake.  Beyond the gain situation, the plot is relatively benign.  There are some hiccups, but nothing major.  Since you had only a small space to work with you chose your dimensions very wisely.  There will be a lot of boundary reinforcement near that rear wall, though.  No shortage of bass in the room.

This is a good room to use the spatial characteristics of diffusion to make the room acoustically bigger than it is physically.  I would suggest diffusion on the rear wall, for sure.  The side wall would use a combination of diffusion centered at the seated ear height with absorption above and below that.  I would use triangular deflectors in the upper front corners to eliminate the comb filtering congestion that WILL happen there and absorption at the ceiling/wall corner between the speaker placement and seating position for the same purpose.

How deep is the furdown coffer around the room?  Have you considered making that a 45 degree cove?  That would be acoustically superior.

Dave

[HT cOz]

Dave thanks for your input!

I ended up not doing the fur down and instead went with the ceiling box for obsorbtion.  It was getting pretty congested up their with the lights, the box, the projector, plus not a big room to begin with.

However, once the the drywall is up I could have the trim carpenter work on a false 45 degree wrap that I could stuff and cover in cloth?  Sounds like this would be good to do in a horse shoe shape until the listing area. 

One of my biggest challenges is going to be finding a good inexpensive material to fill all these pretty big obsorbtion boxes.  I'm really hoping that the building supply company will have something.

The listening area will be located in the area that says 6'-3/8" on the plan.  Would you recomend 1 or 2 pair of ABB? per side?  Should I do something different with the rear boxes maybe take them down?  or just incorporate diffusion at ear height within the box?

Thanks again.

Robert

[dBe]

Dave thanks for your input!

I ended up not doing the fur down and instead went with the ceiling box for obsorbtion.  It was getting pretty congested up their with the lights, the box, the projector, plus not a big room to begin with.

However, once the the drywall is up I could have the trim carpenter work on a false 45 degree wrap that I could stuff and cover in cloth?  Sounds like this would be good to do in a horse shoe shape until the listing area. 

One of my biggest challenges is going to be finding a good inexpensive material to fill all these pretty big obsorbtion boxes.  I'm really hoping that the building supply company will have something.

The listening area will be located in the area that says 6'-3/8" on the plan.  Would you recomend 1 or 2 pair of ABB? per side?  Should I do something different with the rear boxes maybe take them down?  or just incorporate diffusion at ear height within the box?

Thanks again.

Robert

Robert, let's pick these off one at a time.

1.     The best way to do the 45 degree wall/ceiling interface would be to use some 15-7/8" wide rips of soundboard (this allows for saw kerfs) or white face building board and stuff the cavity formed with common FG unfaced insulation.  you can just toe nail them into place and if you use the building board, you can tape and float it and finish it along with the drywall.  The only place you would need any framing would be a lap brace at the butt joints.

2.     I recommend that you use either 1" or 2" type FSK ductboard to fill your boxes and leave an  airspace behind it to form a diaphragmatic absorber to work on some of the bass you will have in the room.  This material comes in 4' x 10' sheets.  I recently bought a bunch to do treatment in a massage therapy place here in Albuquerque and the 1" was $32.00 a sheet and the 2" was $68.00 a sheet.  I used Johns/Manville, but it is made by everyone in the air handling business.  The best part about the material is that it has a scrim sheet on top to prevent the FG fibers from spalling off into the room.

3.     I would advise 1 pair of 48" long ABB1 per side to treat the side walls with the cells run horizontally centered on the listening axis with light or no absorption treatment above the panel.  I don't think you need anything below.

In the rear, I would use the ABB1 with the cells vertical and side to side in that alcove.  I would not use any absorption on the rear wall.

It is very easy to overdamp a room.  The common notion is that a little absorption is good, so a whole bunch is better.  Not so.  Since a room is an energy system it must be treated as such.  We want the room to track the energy input as closely as possible without adding colorations of its' own.  Too much absorption will drain the life out of a listening space and can lead to that "ears sucked out of your head" sensation that is very stressful.  A good room is an energy management system, not a black hole.

I'm a little busy today, but I will try to post a couple of simple line drawings illustrating what I would do in your room.

Later,

Dave

[jtwrace]

I'm a little busy today

Later,

Dave

 
 

[dBe]

 

How did you know?

 

Dave

[HT cOz]

Dave,

Again thanks for the info in this thread, I know everyone has a busy schedule.  Sounds like I need atleast 4-6 pairs of ABB1s.  I'm taking down the boxes on the rear walls. 

If all goes well, I will see you at LoneStar.

Cheers,
Robert