[molach]

Good Morning All,

I have yet another Duct board question (s), My plan is to put to cover the lower half of my room with linacoustic insulation, and the entire front wall, then cover it with GOM. I have been reading many threads here for months, I believe this is a good starting point, then I was planning on adding additional bass traps etc, if necessary later on.

I have been looking for the insulation at some local contractors, I found one that is planning on retiring, turns out, he was a Friend of my fathers, before he passed away. I was asking him about the insulation, he took me to his storage area, and showed me 12 sheets of 1" thick, 6# density foil backed rigid fiberglass board. It was 4' by 10 ' sheets. He said he would sell them to me for $150.00.

I was not planning on using this type of insulation, and I don't have time to study up on it , he plans on auctioning everything off, and they are doing an inventory , and I wont be able to by it after that.

I do know that there should be an air space behind this type insulation for the sound to pass through, How much space would be recommended, also as I mentioned, this is foil backed, will sound pass through the foil backing and into the air space, or should it be removed , it seems th pull off easy, and finally, can I stick to my original plan, and use this type insulation instead of linacoustica, and sill do the wall coverage liked I planned, or is this type better used to make panels


Thanks ED

 

[molach]

Man sorry about the bad spelling, I am on my way to work, Kinda in a hurry


Ed

 

[Ethan Winer]

Ed,


Buy that entire lot before he changes his mind! That six-pound stuff is twice as effective as the usual 3 pound rigid fiberglass, and that's a terrific price. Rather than answer all your other questions here, see the Acoustics FAQ, second in the list on my Articles page:

www.ethanwiner.com/articles.html


As for the foil backing, leave it on and facing the room for bass trapping, and take it off or face it away from the room for mid/high frequency absorption.


--Ethan

 

[jvos]

Ed -


If you don't want it, I'll take it and throw in $50 for your time plus pay the shipping.

 

[molach]

Thanks for the reply Ethan, I have been thinking about this all evening at work, I finally called him back at 8pm and told him I would take the lot,

I have been to your site, read up on your bass traps, I will definitely read your articles, I have always found your posts on acoustics very informative. This is a difficult subject.


Thanks Again,

Ed

 

[Ethan Winer]

Ed,


> told him I would take the lot I have always found your posts on acoustics very informative. This is a difficult subject.

 

[krasmuzik]

Ethan,


I think there are some acoustic engineers with doctorates that will challenge your notion that acoustics is not difficult!


Certainly imagining sound bouncing around a room is not difficult, but actually doing the math to know what a diffusor or absorber or wall system is doing? Rather difficult to blend physics/electrical/mechanical/acoustical engineering with art/music/creativity. Not many people actually are left/right brained enough to even try. Only recently with the advent of powerful computers have the really difficult problems become solveable. Even still when I run a simple program like CARA and it takes days - not what I call easy!


Like yourself I have done your list of things that you claim difficult (violin not cello) - and thought acoustics engineering would be easy - as the rest of your list comes naturally to me. Acoustic Engineering is the most challenging thing I have ever attempted! Yet I also find it rewarding - as with the simple geometric music scales - it fascinates me that math can tell me what I am hearing! How many other engineering fields can directly relate to human sensory perception like that?


Even reading the Master HandBook of Acoustics - which explains acoustics without all the math - still +600pp that you need to find the time to study and learn. I think this is a must read for anyone considering DIY room design/treatment!


Ed,


Good find on that duct insulation. I had my room treated by Owens Corning ARS and I have a pallet full of leftovers. Tried to sell it off to free up my garage and keep the wife happy - but I've decided to keep the stuff to build my next showcase theater! Stuff is hard to find at a decent price!

 

[jvos]

Quote:

All problems in all rooms are caused by reflections off the walls, floor, and ceiling

Isn't this an oversimplification and really only applies to sound that originates from within the room? What about an HT that is adjacent to a bar room where this is a loud party going on? What about wanting to prevent you movie from being heard in the room directly above the HT? In other words, to build an HT you need to consider overall sound control, not just the pure acoustics within the room pertaining to what the speakers in your room are producing.


Am I right or totally nuts?

 

[Ethan Winer]

Kras and JV,


> I think there are some acoustic engineers with doctorates that will challenge your notion that acoustics is not difficult!