Gypsum board as low frequency absorber?

I follow the 1/3rd rule equally for absorption, diffusion and reflection. As I use an OB speakers with an H- frame OB sub, my room is equally energized at both the front and rear side giving a figure 8 polar pattern. This itself take care of much of the room loading issues. I have just used a laminated parabolic diffuser in my first reflection point. Imo, the issue of room treatment takes precedence only for box speakers.
 
@AudioGugu It has worked well for me.

Before trying out the Gypsum Board, I had used 2" thick rockwool panels which did not do anything. I had read about Gypsum Board acoustic properties and decided to give it a go. I bought 2 panels of 4' x 8' each and placed them against the back wall in 3 ways - Flush against the wall, with a 2 " rockwool panel between the wall and the Board and lastly with nothing but a 1" airgap between the wall and the panel. The last option worked best. The bass boom reduced by over 50 percent which was good enough for me and better than what I could achieve with other simple options. Being satisfied with the result, I then had a carpenter make a 1" thick wooden frame and mounted the gypsum board on the frame, followed by putti/painting and all. Pictures attached. I am considering getting an artist to paint something directly on the panel.
The experiment is inexpensive - you get the panels for a few hundred rupees and place them to test the results before permanently fixing them.
Best wishes
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If you can build more or intend to do so, try and seal the air gap to make it more effective. This is to ensure that the waves dont leak from the open edges. One way to do so is to use the same gypsum board have rockwool sheets stuck on the front and back panel and the air gap in between.
 
If you can build more or intend to do so, try and seal the air gap to make it more effective. This is to ensure that the waves dont leak from the open edges. One way to do so is to use the same gypsum board have rockwool sheets stuck on the front and back panel and the air gap in between.
Thanks @sud98 . The boards are sealed on all 4 sides so the air gap is trapped. Subsequently, I drilled a 2mm hole at the bottom of the board. This obviously lets out some air, but the sound has improved significantly. I have drilled similar 2mm holes in my false ceiling with beneficial results
 
This was thrown up as the first result when I googled. The key word here is "respirable" so I'm not sure how relevant this is for boards. But even so, personally, I would not take a chance and I'd wrap it with a a cloth to prevent particles in the air.View attachment 60559
Gysum board/plaster board is not asbestos so it should not be a concern. Its widely used in UK for ceiling and partition walls/dry walls. You do paint on it or wallpaper it. You wont be cutting or saw cut it everyday so that these microparticles are in air.
 
Thanks @sud98 . The boards are sealed on all 4 sides so the air gap is trapped. Subsequently, I drilled a 2mm hole at the bottom of the board. This obviously lets out some air, but the sound has improved significantly. I have drilled similar 2mm holes in my false ceiling with beneficial results
Wow...thanks for sharing that :)

Even I want to try drilling holes in my false ceiling. Is there any ratio to the spacing of the 2mm drill holes please
 
Hi
I have a room size of 21x16.5 feet with 11 feet ceiling height.

Room was equipped with Sonus Faber, Tube amp and DAC with old Nakamichi rack. Room was filled with distortion phase noise, low frequency standing waves. Carpet with underlay and roof with mineral ceiling contribute a minor role but still not satisfied. Room was resonating at frequency of 26 to 30 Hz for three to four seconds delay rest of the frequencies were under control. Lot of efforts made but finally I decided to get help from consultant who made large cinema and have experience of controlling low frequencies. They suggested to come up with gypsum sound boards with small holes in sheets.
Ohh. What a fine treatment. It removed all standing waves and made the audio room very quite and the faintest audio note were appear in music. Blues are so relaxing. Rarely the songs of Lata, Mehdi Hassan seems me performing right in the middle.
It's a wonderful experience.
I would like to know that will my post be visible to all members or only to specific members. How can I generalized my statement on acoustics of room.
 
My listening chair is against the rear wall. This results in relatively strong bass at that position, although the bass a little further into the room towards the speakers is more balanced. Someone advised me to use gypsum board on the rear wall. It works! And if I leave an air gap between the board and the concrete wall it works even better. Better than rock wool.

Would like to know if any of you have experience with gypsum boards. Any information on the acoustic properties of gypsum boards will also be useful - does it absorb specific frequencies, etc. And what is the air gap doing?

Than
 
Hi Dear,

Your room size is very important. You need treatment at the corners, the bass traps. You will find it from Google about it. It is relatively easy approach, before going to invest more.

You need little experimentation with the room. Clap at all corners first and watch the echo. If reflection remain present more than 1 second then you need treatment for middle frequency.
Now you drop empty box of card board approximately 2x2 feet in all 4 corners and watch the low frequency if it persist more than 1.5 seconds again you need treatment for low & high frequencies. Please share experimental results than I can suggest your further on it.
Thx
 
Why not a Cork sheet? I have been googling anti vibration cork sheets/blocks to put under my Tannoys and discovered they absorb sound well.. You can place a 3 x 2 feet 25 mm thick standard size cork sheet on the wall behind you to absorb sound...May be cover it with a cloth if it doesn't look nice to you...

As an added bonus, while you are listening to music, someone can throw darts at the board behind you...
Corks are good absorbers. I use them under every device in the stack. Does their job.
 
My listening chair is against the rear wall. This results in relatively strong bass at that position, although the bass a little further into the room towards the speakers is more balanced. Someone advised me to use gypsum board on the rear wall. It works! And if I leave an air gap between the board and the concrete wall it works even better. Better than rock wool.

Would like to know if any of you have experience with gypsum boards. Any information on the acoustic properties of gypsum boards will also be useful - does it absorb specific frequencies, etc. And what is the air gap doing?

Thanks
Just curious, have you tried DSP or just a simple high pass filter filter between source and amp ?

On the other hand you can contact armstrong tiles who do make tiles for acoustic treatement and they should be able to help you.
 
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Gypsum has a very low absorption coeff. so I'm not sure how it is helping. But since this is frequency dependent...
 
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Just curious, have you tried DSP or just a simple high pass filter filter between source and amp ?

On the other hand you can contact armstrong tiles who do make tiles for acoustic treatement and they should be able to help you.
I have tried DSP but i think Gypsum board did a better job. As the board + air gap worked, I don't see a need to now contact the tile company
 
It would be more convincing if there is an objective measurement of the room with/without the Gypsum board installed. An RT60 graph would be ideal. Subjective assessment is okay for someone who understands their room and has their own set of preferences.

I'm interested in this topic and would be curios to see the results. I do have some resonance in the lower frequencies. These are really hard to tame. The usual direction seems to be bass traps at the corners. Since, my issue is only with 150 Hz and below, using a graphic equaliser seems to be a decent solution for the time being.
 
Just wanted to share my small experience, My room had boomy bass and standing waves issue, I tried many treatments it didnt solve much, recently I got the room flooring done and used SPC tiles which uses a foam layer underneath as my old flooring was getting damaged. To my surprise suddenly after flooring done the boominess of the bass is not noticeable anymore, sound is much clear and bass feels tighter....If I knew before I would have done the flooring much sooner.
 

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Just wanted to share my small experience, My room had boomy bass and standing waves issue, I tried many treatments it didnt solve much, recently I got the room flooring done and used SPC tiles which uses a foam layer underneath as my old flooring was getting damaged. To my surprise suddenly after flooring done the boominess of the bass is not noticeable anymore, sound is much clear and bass feels tighter....If I knew before I would have done the flooring much sooner.
Are these wooden tiles?
 
Just wanted to share my small experience, My room had boomy bass and standing waves issue, I tried many treatments it didnt solve much, recently I got the room flooring done and used SPC tiles which uses a foam layer underneath as my old flooring was getting damaged. To my surprise suddenly after flooring done the boominess of the bass is not noticeable anymore, sound is much clear and bass feels tighter....If I knew before I would have done the flooring much sooner.
I am not surprised. Have experienced this myself.
 
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