[bassboy]

There is currently nothing in the room except a huge dusty mess from blowing insulation into the walls (they FINALLY got it finished yesterday.  Once it gets cleaned up, the speakers will be placed along the 19.2 foot wall ( the wall in the pic that has the door that I want to cover with a diffusor)  So the front of the room will be the top of the pic.  The speakers will be set up wherever they sound best - this room will be dedicated, so no furniture or anything to get in the way.  Not sure of the exact (to the inch) placement of the speakers, but I can try any or all of the many recommendations to get the best sound.

The listening position will be about 38% from the back of the room, which seems to be favorable based on stuff I've read.  This spot is also open to variation depending on what sounds best in reality.  A 38% from the back position would put me just a bit behind the window on the left side wall, with the hallway opening immediately to my right.

Regardless, I want to set up along one of the short walls, I can reverse the direction if you or anyone else thinks it is best, but I do not want to place the speakers along the long wall.  In reality, at this point I'm not dedicated to any seating plan.

But using the short wall speaker position scheme with the small door in front of me and the big garage door behind seemed to make sense to me, since the natural spots to place diffusors to catch the first reflections would allow me to cover the window and door completely, since they happen to be right in the middle of my first reflection points.

Please don't waste your time writing volumes about theory that is all covered somewhere else anyway just for my benefit.  I openly admit I have not done nearly enough research on the subject yet.  My old room had no space to add any treatments of any kind, so I never did any research.  I've only been in the new room about 3 weeks now, so just started my research.  Simple rules of thumb are great.  I actually wasn't expecting to ask anything more than the original 1d or 2d question, so I'm a bit behind on a bit of this stuff.

But so far, according to rules of thumb

1.  I will NOT be making a huge singular panel based on a massive prime number.
2.  I will be using a combination of prime 11 and 13 diffusors, arrayed in a checkerboard pattern to cover the desired area.
3.  The diffusor design will be an old school Schroder design, fins and all, built to tight tolerance and well sealed, based on a well width not less than 1 inch, but less than 2 inches with no cloth covering
4.  The diffusor panel arrays will cover every first reflection point (front wall, both side walls, ceiling, back wall)

Is this all ok so far?

[Jason Jones]

1. Yes.
2. Yes.
3. Yes, I would go just about 2" not much more or less. Make the 11's a hair wider and the 13's a hair narrower so they are both the same total width - 24" would be good.
4. This is all fine. I'll try to post a picture of your room and something that I think would be ideal for the combo of your room and (what I know of) your preferences. Though, on the ceiling, PLEASE make sure you have everything SECURELY FASTENED!!!!!!!

Jason

[bassboy]

The ceiling diffusors will be the last to be installed.  I'm actually going to strengthen the existing trusses a bit (or a lot).  I never even bothered to look up there until the insulation guys came, and now that I have seen it, it needs some work.  No problem though.

[satfrat]

You should be pleasantly surprised when you hear the difference with that ceiling diffuser at the first reflection point. Mine really opened up my 11' x 17' x 7' room. I think more guys with low ceilings should be giving ceiling treatment a good hard look. 


GO RED SOX!

Robin

[bassboy]

Yeah, it's going to be a huge project and I'm hoping for the best.  With a huge room like this, it's time to get a bit more serious wrt good sound.

[Jason Jones]

Wow this really is going to be a big job for you! And, wow I had a hard time making all of the software conversions necessary to upload this drawing (5, I think)!

Anyway...this is your room and you want the windows covered, correct? Also, the back wall is a garage door that you want covered?

I am having technical difficulties and cannot post this picture. Here is the link: http://www.audiocircle.com/index.php?action=gallerylastup&cat=0&pos=0

Jason

[Glenn K]

Wow this really is going to be a big job for you! And, wow I had a hard time making all of the software conversions necessary to upload this drawing (5, I think)!

Anyway...this is your room and you want the windows covered, correct? Also, the back wall is a garage door that you want covered?

I am having technical difficulties and cannot post this picture. Here is the link: http://www.audiocircle.com/index.php?action=gallerylastup&cat=0&pos=0

Jason

Here you go jason

[bassboy]

Wow, that's a much better pic than mine was.  Your rendering is pretty close, except for the back right corner, as illustrated below.  Also, in your rendering, it looks like the window to the listener's left side is offset towards the back, when in fact it is a few inches closer to the front wall than the back wall.  If I made a mistake when describing that before, I apologize.  The back edge of the window and the front edge of the hall are ~even at ~about 16.25 feet feet back from the front wall, give or take a few inches, IIRC.

Anyway, it's definitely close enough to get the idea.

I wanted to cover the entire door frame and window frame, but not the entire garage door (pictured in illustration below).  I just wanted something that looks kind of symetrical to the front wall diffusor, a stand alone unit to place back there somewhere.

Thanks so much for your time.

[Jason Jones]

Bassboy,

Could you write over the top of that drawing (i.e. 4'x8' of diffusion here, etc.) Then I'll make a suggestion or two and then....to the woodshop!

Jason

[bassboy]

Ok, here's the general areas.  Notice the circles around the speakers and listening position.  The speakers and listening position could end up anywhere within these circles, whatever sounds best, and dictated by the position of the side window covering diffusion panel.

The front (green) panel needs to be 6 feet wide by 8 feet tall minimum.

The side (orange) panels should be the same size as each other (symmetrical), and to cover the side window must be minimum 56 inches x 56 inches, so I could make them a bit larger (6 feet x 6 feet) if we are making 2 foot square units.

The ceiling and back wall panels (blue) can be any size you think would be best (6x6, 6x8, 8x8, etc)

The green and orange panels can be larger than noted above, if you think there is sufficient cost vs performance ratio.

[Jason Jones]

This is going to be a really, really big job. I am counting 46 panels before the ceiling gets treated.

On the sidewalls 6'x6' is fine. You have 3 options:
1. Make a total of 18 panels (9 for each side) make 10 of them an "11 well" and 8 "13 well" or vice versa.
2. Make some larger - i.e. 2'x4' panels and make fewer if that will save you time.
3. Use all "11 well" or all "13 well". In a checkerboard pattern, where one is vertical and the next is horizontal.....you really don't need to worry about mixing the 11's and 13's. This si my recommendation.

On the front wall at 6'x8' you have the same options as the sidewalls. I would recommend the checkerboard pattern with all of them the same (11 or 13), but use a different number than on the sidewalls.

For the back wall, I would go pretty wide....10' wide by either 6' or 8' tall. This is really the place where you can make tall diffusers if you want. 2'x4' or 2'x6' or even 2'x8'. Here you will need to mix them up some 11 and some 13 if you make the tall diffusers. I would recommend this option here. You would need to make 2 of one (11 or 13) and 3 of the other.

Jason

[bassboy]

Just a couple of questions before the saw hits the wood.

1.  How deep should the panels be?  (2 feet by 2 feet x ?)

2.  Do I need to keep the fins?  It would be SO much easier to leave them out.  And I've noticed several designs that don't use them. 

Thanks again.

[Jason Jones]

The depth should be 6-9". It is a trade-off between working deeper and increasing absorption. At 6", it will work down to about 565 hz. At 9", it will go down to about 400 hz. When you have a smallish stand of diffusers (+/- 4' x 4') you get quite a bit of lower (down to 100 hz) dispersion from the "edge effects". Your call.

With a standard QRD sequence, you really do need the fins. I know I have research somewhere in my office detailing an optimized design for a base 7 QRD without fins. It is possible that article also discussed longer sequences. That was one of the things that we worked really hard on with our D1 diffuser - getting no compromise performance without the well dividers (fins). Sorry...but I wouldn't compromise here.

Jason

[bassboy]

No need to be sorry - I'll take my time and do it right (with fins).

Is the online calculator at http://www.mhsoft.nl/diffusor.asp#calcul a good tool to use to design my diffusors?  It seems ok to me, but what do I know?

(Sorry for all the dumb little questions, but since I need to build almost 50 of them, I just wanted to make sure)

[Jason Jones]

That calculator is fine. Just to point out the obvious, those well depths listed on the mhsoft site are distances from the front/opening of the well.

Good luck! Please post pictures and feel free to ask any more questions (just as long as they are not woodshop questions - I'm not too talented in the shop.  )

Jason

[Glenn K]

Good luck! Please post pictures and fee free to ask any more questions (just as long as they are not woodshop questions - I'm not too talented in the shop.  )

Jason

fee free?  Now everyone knows what you are really thinking JASON. 

Glenn

[Jason Jones]

Good luck! Please post pictures and fee free to ask any more questions (just as long as they are not woodshop questions - I'm not too talented in the shop.  )

Jason

fee free?  Now everyone knows what you are really thinking JASON.  Glenn

You think that's bad. Once, in an e-mail, instead of typing "I don't mean mean to cause offense" I forgot the "don't" and wrote "I mean to cause offense". That time the typo wasn't so obvious.

Jason

[Ethan Winer]

I forgot the "don't" and wrote "I mean to cause offense". That time the typo wasn't so obvious.

One of my frequent errors is typing "now" instead of "not." The "w" key is nowhere near the "t" key so I don't know why I do that. But it's really embarrassing to not catch it when I write "I am now trying to be argumentative."

--Ethan

[Inscrutable]

Kinda quiet on this thread lately.  Hope bassboy isn't lying unconscious next to the table saw or router station, especially since I need to learn vicariously thru this thread before I start my own similar project.   

[Inscrutable]

Off the wall question while we're waiting for bassboy to recuperate    Has anyone tried to build these with the fins as forms (do you use something like masonite or thin plywood) and rather than ripping wood,  use some kind of flowable fill to pour in to create the wells?