How to diagnose the need for room treatment?

Sandhya,

Thanks for bringing up this thread of mine again. A year and a half has gone by and I've done a fair amount of further reading and experimentation and things have improved, and I'm still working on improving things further. This might be the second most interesting aspect to being an oddiophile (ja!), following the enjoyment of music itself, of course.

I'm surprised you cant't find fiberglass panels in India. Where are you looking for them, may I ask? I say this because I'm in Argentina and I can find them at construction supply stores. Both the panel and the fiberglass wool are used as insulation for construction and industrial applications.

Horacio

Horacio,
Congrats on last nights win by argentina into q/f.

Last since I posted, after further reading I came to know that this is the same thing which is used for A/C Insulation. We do find it over here.

I have more questions.

1. What is the amount of insulation we need to do. 1 in or 2 inch. How do we determine.

2. I suppose we need to make wooden frames, fit the fiberglass wool and then what do we need to cover it with. Fabric is the only choice.

3. How much of % of walls do we need to cover it with. Is there a possibility that the room would become not lively or dead.

You say you are experimenting. How are you doing it.

Can you let me know few examples.

Thanks
Sandhya

Sandhya,

Thanks for the compliments. It's a big deal in this part of the World!

To me it has been worthwhile learning about this. The two books I have are Alton Everest's master Handbook of Acoustics and Floyd Toole's Sound Reproduction. Both very good and they complement each other nicely.
I've been reading a lot over the internet too. Examples: Real Traps website, as well as the other websites mentioned obove on this thread.

As far as your question about fiberglass thickness and how much and placement. It depends!!
Treating some of the first reflection points is important, and for that you can use 2" fibeglass panels of 50 kg/m3 placed against the wall.
For bass absorption you'll be better off with a fair amount of space between the panel and the wall, at least 4" space, and a 4"-thick panel.
Check out Audio Asylum for Jon Risch's panel recepies. same for bass tube traps.
For covering the fiberglass I use polyester batting (cheap insulator used for mild-cold weather jackets).

My way of experimenting has been listening and taking measurements with a Radio Shack SPL meter when changing speaker and listening positions, building 2 large bass tube traps, building 2 3"-thick panels for front wall first reflection points, and building two 4"-thick self-standing panels, and adding a thick wool carpet on the floor first reflection points. I'm now building a larger panel for a specific place where I suspect it will be very beneficial.

This takes time and effort, though, and is oftentimes frustrating. So be aware of it before going in. It pays off, though!!

Sorry for the long post.

Horacio

Listnening priorities : 70 Music vs 30 Movies.
Last few weeks I have been studying about Room treatment.

Few Decisions I have made.

Currently my room is 17' 4" X 12' 3" X 9'. Initially thought of increasing the size to 22' ft in length. Gave up the idea as it involved more civil work, more expenditure etc. Also I thought 17 ft is not too bad of a size of a room. Also Will be creating Acoustic panels such that they can be removable.

Acoustic treatment design will consist of two parts

1. Broadband absorbers which will be positioned on the side, back and front walls.
2. 3 Superchunk(right triangle rockwool from floor to roof) bass absorbers.4th one I cant use as there is entrance door situated there.

All the acoustic panels will be 4 inches thick. Will be using 96 Kg/cu.m Rockwool.

My side walls will contain 6 ft width X 4.5 ft Height panels. There will be three panels each of 2 X 4.5. These will be positioned based on the first reflection points. These will be hung 2 inches away from the wall. To hang them away from the wall I will be using a A nut bolt method where the screw will be embedded into the back part of the panel. The front part of the screw with the head will be inserted into the frame hanger which is fixed into the wall. This is like frame being hung on to the wall but the nail is on the frame not on the wall. Another advantage with this method is I can remove them and change the spacing between wall and panel by rotating the screw to 0,1,2 or 3 inches. I will be using 4 inch nut bolts.

My Back wall is pretty close to my seating position I will have a 6ft by 4.0 ft panels. I dont have too much space so I am planning to stick them to the wall leaving no space between the wall and panel.

My front wall where I hang my projector screen will be covered with absorbtion panels about 8ft X 5 ft. It will starting at 32 to 34 inches from the bottom and reaching up till the roof. My 32 inches from the floor will be covered by my new HT rack. Same with my front panels, I will stick them to the wall leaving no space between wall and panel.

Question : My Projector screen will be hanging over this absorbtion. The screen will always be pulled down. The spring action which the screen had is all gone. Will this be a problem for absorbtion not happenning. If so I might need to fix my screen such that It will go up as and when required.

My Front two corners will contain two super chunk corner bass absorbers. The dimensions of each being 17X 17X24 inches. I can only use one back super chunk corner bass absorbers of size 15 X 15 X 21 inches. On the other corner I have the entrance door situated.

I might treat my center of my ceiling with 4ft by 12ft with 12 ft being parallel to the speaker line and 4ft being the width. Not decided yet. Currently my room's fall ceiling is already done. Dont want to disturb it. If at at all I do it it would be such that I will run two Iron rails parallel to the Speaker line. Then hang the absorbers to the two rail lines. Before I commit to this I will test it without the ceiling absorbers and then decide about it.

Let me know your opinions.