Finally acoustic treating my room. I have a few Q's

[O.G. Killa]

Originally Posted by fenderrocker

I plan on buying 9 boards (they come in packs of 3), but I might get 12 just in case. How many panels and how many membrane absorbers should I build? And where in the room should I place them?
http://i.imgur.com/tsL3R.jpg
(the green panels on the right wall are labeled 4 and 5. idk why my scanner cut it off)

What do you mean by "boards"? Do you mean the Minwool?

Here's some more reading info for you including some diy info on how to build membrane absorbers...

http://www.ethanwiner.com/basstrap.html
http://www.harbeth.co.uk/usergroup/s...Panel-Absorber
http://www.bobhodas.com/pub4.html
http://www.ethanwiner.com/acoustics.html

[fenderrocker]

Originally Posted by O.G. Killa

What do you mean by "boards"? Do you mean the Minwool?

Here's some more reading info for you including some diy info on how to build membrane absorbers...

http://www.ethanwiner.com/basstrap.html
http://www.harbeth.co.uk/usergroup/s...Panel-Absorber
http://www.bobhodas.com/pub4.html
http://www.ethanwiner.com/acoustics.html

from ethanwiner.com:

Control room floors are sometimes carpeted, sometimes wood, and often a combination of the two. Ceilings in these types of rooms also vary between fully reflective, fully absorptive, or a mix of surface types. There is no one correct way to treat every room because different engineers prefer a different amount of liveness. However, you should never make a room completely dead because that produces a creepy and unnatural sound. The only time you might consider making a room entirely dead is when treating a small vocal booth or a very small studio or control room - smaller than, say, ten by ten feet. When a room is very small the reflections are too short to be useful and just make the room boxy sounding.

well... that's discouraging. Just how "dead" will my 11' x 12' 8" room be after putting up 7 absorption panels and 2 bass traps? After reading that, I feel like I might be disappointed with the results so I'm debating whether it's worth the effort.

[fenderrocker]

One more drawing: http://imgur.com/KllYP.jpg

The reason the back middle one isn't a bass trap is because you said they can be reflective in the mid-range. The bottom right vocal isolation also doubles as a bass trap. Is there anything special that I should do with the bottom left bass trap? How about the open space on the left and right walls?

[fenderrocker]

Ok, one last question guys.

Can someone clarify what the chart means by "1/3 Octave Band Center Frequency"?

http://www.insulation.org/mtl/pdfs/000072_439.pdf

[O.G. Killa]

Originally Posted by fenderrocker

from ethanwiner.com:



well... that's discouraging. Just how "dead" will my 11' x 12' 8" room be after putting up 7 absorption panels and 2 bass traps? After reading that, I feel like I might be disappointed with the results so I'm debating whether it's worth the effort.

That's why I've been saying, start sparingly and add to it, and also why I've been saying it is never going to be perfect.

[O.G. Killa]

Originally Posted by fenderrocker

One more drawing: http://imgur.com/KllYP.jpg

The reason the back middle one isn't a bass trap is because you said they can be reflective in the mid-range. The bottom right vocal isolation also doubles as a bass trap. Is there anything special that I should do with the bottom left bass trap? How about the open space on the left and right walls?

Very cool. Looking pretty good. You are still going to do the diffusor on the back wall right? It isn't in the latest drawing.

I don't know if you've read how to find the perfect place to position the minwool panels, there's a mathematical way to do it... and there is the quick and dirty way to do it.

I'll explain the quick way. You'll need a friend to help you with this. You'll also need a hand mirror (a small one is fine) and a pencil and maybe a step ladder or stool.

the concept is to have your friend hold the mirror on the surfaces of the room while you sit at your listening position. Sliding it along (up down left and right) until you can see either speaker in the mirror. As soon as you can see either speaker, mark that spot on the wall with pencil... then continue moving until you can't see the speaker, mark that spot as well. Then continue moving until you can see it again, mark it and so on.

When you are done you'll know the EXACT spots on the walls and ceiling (which is why you'll need a stool or step ladder, do the same process on the ceiling above you) where sound directly reflects back at you.

You'll probably notice the spots are pretty small. maybe a couple inches in diameter to maybe a foot in diameter. You'll notice the panel is A LOT bigger than the actual spot marked on the wall with pencil. That's ok. The bigger the panel, the more "wiggle" room you have in the mix position, literally. It allows you to move around a little in the mix position and still be within the "reflection free zone". Which, by the way, that term was coined buy an AMAZING acoustic engineer named Dave Moulton. Google him and read some of his work if you are interested. He also has a set of Audio CD books called "Golden Ears" which are amazing and should be required of every sound engineer to learn.

Anyway... sorry for the Moulton tangent! LOL back on track...

On the back wall behind the listening position, you'll notice since you are so far away from the speakers, there is a large area of the wall that reflects back. This is why I suggested putting the diffusor across that whole section. It'll keep the room a little lively, flatten out the freq of the room and keep sound from echoing back at you. But you could put panels up if you want.

The bass traps... yes they reflect high freq sound since it is basically a piece of plywood with cloth over it. BUT!!! since bass is omni direction you can put them in spots where they won't reflect sound right back at you. For example, instead of attaching two on the WALLS in the corner, you could attach them to the ceiling in the corner and have them facing the floor. They'll be just as effective. Maybe make an "L" shape out of them on the ceiling in the corner where the window is. If you have clearance above your door and closet, you could put two more up there. Same for the corner where the bathroom door is. You might not need SIX, but each one of those spots is a possibility. You could also have a couple angled between the ceiling and wall if you want.

For the mic corner, it looks really good! Just make sure you do floor to ceiling minwool and put minwool ON THE CEILING over the singer and mic. you want that whole corner to be covered in minwool panels.

If you look in this picture, you can see how you can use a 1" x 1" frame around the minwool up against the walls.

http://c3.ac-images.myspacecdn.com/i...beb2491462.jpg

This is the room I mentioned that is completely covered in 703. While I don't recommend doing that. The technique used could be used at your place to make the mic corner look nice. Basically the Minwool would be nailed, tacked, or drilled into the drywall... then leave a couple channels in it for the 1" x 1" frames. build the frames and staple the cloth over the frames...then put the frames up over the minwool You can use finishing nails (no head) to tack the frames into the drywall.

Those vertical seams you see running down the far wall in the picture are where one 1" x 1" frame ends and another one starts. underneath each panel there are six 2' x 4' panels of 703 (two columns, stacked three high). Technically, the top panels are cut off, the ceiling is between 9' at the lowest point and about 12' at the highest point... but you get the idea. The ceiling in the room, (which you can't really see in the picture) is done the same way).

So you could try to do that in the vocal mic corner. It would look nice and it's pretty easy to put up and take down (when you move out). We also run cable under them so we take them off and put them back up frequently It works really well.

[O.G. Killa]

Originally Posted by fenderrocker

Ok, one last question guys.

Can someone clarify what the chart means by "1/3 Octave Band Center Frequency"?

http://www.insulation.org/mtl/pdfs/000072_439.pdf

these links might help you start to understand...
http://www.noisemeters.com/product/s...tave-bands.asp
http://www.prosoundweb.com/article/c...ualization_eq/

http://en.wikipedia.org/wiki/Equalization

An octave is a doubling in frequency. So, we all know 440Hz is A below middle C. An octave below that would be 220Hz. An octave above 440Hz would be 880Hz. and so on.

When making measurements, they blast noise at the panel and measure how much sound gets through it by putting a mic on the other side.

They are stating that they used some sort of RTA (real time analyzer) or software to read the freq response of the mic placed on the backside of the panel. That RTA or software has a resolution of 1/3 of an octave, centered on each frequency listed.

So... a 1/3 octave resolution means that if the octave goes from 220Hz to 440Hz... 1/3 of that is?... 73.34Hz So the first 1/3 octave band would be from 220Hz-293.34Hz. The next band is 293.34-366.68. The next band is 366.68-440Hz. Any frequency amplitude or attenuation within the band gets averaged together into a single "point" on the graph representing the frequency amplitude for that band. The combination of all these "dots" creates the frequency response graph.

As you can see it's good for getting a rough estimate of the overall acoustic performance of something, but you can't see fine details. For an acoustic panel specs you don't need to see the details, you can see the overall trend of how it absorbs from the 1/3 octave or 1 octave measurements.

But if you are measuring the frequency response of your room, you really do need it. So for analyzing your room, you'd want to try and use software that has AT LEAST a 1/24th octave resolution or higher (1/48th, 1/64th, etc). Using these higher resolution analysis meters allows you to see the standing waves that might be at one single frequency.

[fenderrocker]

Alright, sorry for abandoning this thread for so long. I've been caught up with school work and what not.

Here is the first panel my father and I built. The fabric is a really cheap felt (but it feels and looks pretty nice). Overall, this panel cost me ~$34, including the hanging mechanism (we put wire hangers on the back, so it hangs up like a picture frame).

The back has paper on it, similar to a picture frame. Here is what it will look like. Just thought I'd get some of you pro's opinions before I build the rest of these things.

http://imgur.com/U490r.jpg

[O.G. Killa]

Very cool man. Great work! In the end how they look is secondary to how they make the room sound. So long as it's working you can tweak how it looks later.

[fenderrocker]

Originally Posted by O.G. Killa

Very cool man. Great work! In the end how they look is secondary to how they make the room sound. So long as it's working you can tweak how it looks later.

Thank you.

I have started some plans for the vocal "corner" you suggested previously. I'm not sure exactly how I want to build it, but here's the first design I drew up based on the lot of panels I had bought (could fit in my car ).

http://imgur.com/heXf0.jpg

Imagine that in the corner like this:

http://i.imgur.com/86QwGl.jpg