Question about heavy, 2-300mm DIY traps.

[kurt]

Originally Posted by Glenn Kuras

On a 4 inch panel it will give you something like 50% more absorption if the sides are open..
Glenn

Hi.
Can somebody,Glen, explain this to me, if possible with metric values?
PS.
Is anybody, in stead of wood which is nice, has weight & stability, looking at plastic or metal "profiles", to build a solid, acoustically invisible like "Stealth" frame around the (heavy) trap?
Thnx.

[Glenn Kuras]

If the sides are open then it then has more area of absorption.

[kurt]

Originally Posted by Glenn Kuras

If the sides are open then it then has more area of absorption.

But 50% more?

[Glenn Kuras]

Way to early here in the states to think math, but check it. I will say that my statement of "absorption" should be "absorption area". Meaning it might not increase the sabins per unit by the same amount percentage wise of uncovered area. The point is when the sides are exposed it gives more area to absorb.

Also as good as that is, if you are looking to make the panel with framed sides it would not be wrong, so do what ever works best for you.

[statictrash]

I just put together about 18 of these based on this design.

edit: i can't seem to get the youtube video link to post here, so do a google search for "diy bass traps" and you'll see the video pop up in googles youtube results.


Super light weight wooden frame. The rest is all fabric and they look good and work very well.

Here's a shot from my room.

[kurt]

Originally Posted by statictrash

I just put together about 18 of these based on this design.

edit: i can't seem to get the youtube video link to post here, so do a google search for "diy bass traps" and you'll see the video pop up in googles youtube results.


Super light weight wooden frame. The rest is all fabric and they look good and work very well.

Here's a shot from my room.

My entire tracking room, looks like that. :-)
-I would like to build a 3 sided basstrap around the roof that has a standard office sound "isolation". The room is 63m2 big. & instead of improvised, all over, after kind of material isolation of reflecting walls, mount some heaver wall-traps, listening to my empty & bass shy room.

[Ethan Winer]

Originally Posted by kurt

But 50% more?

The drawing below is from my article Alternative Test Methods for Acoustic Treatment Products. Here's the accompanying text:

Figure 2: This panel is 2 by 4 feet by 4 inches thick. During testing the edges increase the total surface area by 50 percent, yet the edge surface is excluded from the calculation to absorption coefficients from sabins. Further, when a group of panels is mounted adjacent to cover an entire wall or ceiling, none of the edge surfaces are exposed, even though some of those surfaces absorbed during testing.

--Ethan

[kurt]

Originally Posted by Ethan Winer

The drawing below is from my article Alternative Test Methods for Acoustic Treatment Products. Here's the accompanying text:

Figure 2: This panel is 2 by 4 feet by 4 inches thick. During testing the edges increase the total surface area by 50 percent, yet the edge surface is excluded from the calculation to absorption coefficients from sabins. Further, when a group of panels is mounted adjacent to cover an entire wall or ceiling, none of the edge surfaces are exposed, even though some of those surfaces absorbed during testing.

--Ethan

Thank you Glen & Ethan very much for the explanations about edges.
I’m hearing you..

-I’m thinking of make something off 18 pcs 120x55x10cm 20-25kg piece, hard pressed Rockwool. At the back & early reflections zones in CR, & maybe tracking room. 1-2-3 layers. I have assortment of many other m2 diverse glass & rock-wool bats. Tips on sandwiching? -This has been underway for many years :-)
Cant stop thinking that combination of perforated frame made of aluminum or some horn plastic products & fabric, seems obvious.

But complicated for a woodman as I’m.

[Glenn Kuras]

Tips on sandwiching?

Just stack them up.

[kurt]

Originally Posted by Glenn Kuras

Just stack them up.

Just collecting ideas. What do you mean?

[Glenn Kuras]

Maybe I don't understand your question, but you don't need to glue the pieces together. Build a frame and stack them inside of it.

[kurt]

Thank you for all answers.
Now. I´m going to reconstruct my flush mounting attempt & put back a bigger speakers + the old main par.
With a demo copy of the FuzzMeasure, I have taken L-R (before) measurements off my:
Dynaudio BM15A
Tannoy DMT 15 II &
Genelec 1030A
What are differences on L. channels off Dyns. & Gens. telling?

[Ethan Winer]

You'll do better to post graphs of frequency response rather than impulse response.

--Ethan

[kurt]

Originally Posted by Ethan Winer

You'll do better to post graphs of frequency response rather than impulse response.

--Ethan

I will, (doing so many other tings right now.)
Are grapfs I posted indicating reflections or some form of electrical fault?
PS.
I will upload graphs, pictures & questions here:
FuzzMeasure