Ink

[Glenn Kuras]

It will decrease the absorption on the upper frequencies. Also it could start to act as a membrane but I would not think it would improve the lower frequency absorption by all that much. You would just have to try it and see.

[Rod Gervais]

I am interested which book you read this in.

I can see how it would affect high and perhaps high mids - but do not see in my mind's eye any increase in LF absorption - like Glenn said above - you would have to test it... and I don't know that a roller would be my method of application if I were interested in this.....

Rod

[Rondeath]

hey Glenn and Rod, thanks for the reply.
It is allowed to draw a similar graph to the book and post here?

[Rod Gervais]

there can be issues with posting copyrighted materials - however - as long as you propery identify the source, the detail you post is in it's entirety - and is done strictly for the purpose of gaining additional info - it is not really a copyright issue....

Rod

[Rondeath]

Hey Rod,
You saw the picture that I sent? The name of book in english is
" acoustic applied to noise control, Bistafa,S.R. (The real name is in my native language)
In this book, he does not enter into detail. Just shows a graph and a brief description.
The graph (absorption coefficient x Freq) is cited as the source "Gonzalez, M.F.

[Rod Gervais]

S.R. Bistafa is a widely recognized expert in the field of acoustics.......

Understand though that everything has to be taken in context - thus seeing a simple chart - with no understanding of everything that accompanied that chart - is not in and of itself an answer to a question.

Rod

[gullfo]

and his paper http://www.acoustics.org/smallrooms.pdf is an excellent reference to get started with...

[Rondeath]

pretty hot .pdf. thanks gullfo.
Rod, He explains sound absorption, after a long text, he puts a frame with 4 images.
"Image10.4 -> Factors influencing the sound absorption of porous / fibrous."
There are 4 images. Thickness Variation, Variation of Density, Effect of Air Layer and Effect of application of paint.

The image of paint application is something like that :
View image: Ink

Just wanted to know if someone already made this experience with measuring, although each room can have a different result.
I think I'll test.
Thanks Rod