acoustics help needed

[west10100]

Dear forum members , I am planning rockwool with burlap for acoustic panels and bass traps. Need your experience in building DIY rockwool panels and traps.
My room is 16 feet long and 11 feet wide with window on the right wall in the middle area and door on the left wall at the end.
Have another door on the back wall too which is thin plywood and it rumbles with bass.
What should be done , help needed.

 

[Nikhil]

FM Santy posted a very nice thread on DIY panels he made for himself.
It might be of some help for you ...

http://www.hifivision.com/diy/40966-home-made-acoustic-panels.html

 

[sdurani]

For broadband absorption, make them 4 inches thick and space them 4 inches from the wall.

I would cover as much of the front wall as possible (to improve the front soundstage) and at least the middle half of the back wall (for the same reason).

 

[west10100]

For broadband absorption, make them 4 inches thick and space them 4 inches from the wall.

I would cover as much of the front wall as possible (to improve the front soundstage) and at least the middle half of the back wall (for the same reason).

my fornt wall is occupied with fixed frame screen 120 inch diagonal. I have only 18 cm on each side of the screen left and around 50 cm in the bottom, Would covering them lone help? Or should I place panels behind the screen. Will the acoustics benefit from placing panels behind the screen ?

I will cover the side and back walls as you suggested
Regards
Arun

 

[sdurani]

Will the acoustics benefit from placing panels behind the screen ?

Not unless it is an acoustically transparent screen.

I will cover the side and back walls as you suggested

I never suggested covering the side walls.

 

[west10100]

But wouldnt covering some points on side wall help to tame first reflection points?

 

[jenson]

But wouldnt covering some points on side wall help to tame first reflection points?

http://www.hifivision.com/diy/40966-...ic-panels.html

 

[sdurani]

But wouldnt covering some points on side wall help to tame first reflection points?

Of course, but that narrows the soundstage. Every blind test done shows that listeners prefer to hear side wall reflections rather than have them absorbed, since lateral reflections result in greater spaciousness.

My tastes are no different from those listeners, preferring a wide soundstage, which is why I would never suggest absorbing side wall first reflections (at least not from the nearby speaker, though it can be helpful to absorb them from the opposite speaker).

If you want to absorb early reflections, then that's your choice, but let's not pretend I suggested it. The best thing to do is temporarily hang those panels on the side wall first reflection points and see whether you like the effect or not. Your set up should be designed to please you, not me or anyone else.

Read section 9.2.1 (it's only half a page long) from Floyd Toole's final research paper:

http://www.aes.org/e-lib/download.cfm?ID=13686&name=harman

 

[jenson]

http://www.aes.org/e-lib/download.cfm?ID=13686&name=harman

funny...i suddenly love reflections interesting article...still need to digest a lot of information though

 

[sdurani]

funny...i suddenly love reflections

For me, the key to addressing reflections is direction. It's OK to like reflections coming from certain directions but not like them when they come from other directions. Each person has to decide what their preference is and treat the room based on that preference.

For example: do you want reflections bouncing off the front wall, coming from the same direction as the phantom imaging you're trying to hear between your speakers?

Since side walls can act as acoustical mirrors, do you want the sound from a speaker reflecting off the nearby side wall and making the front soundstage appear wider than the room?

Do you want sound from a speaker bouncing off the opposite side wall? That means sound from your right speaker will also come at you (however subtly) from the left side of the room.

The good thing about all this is that none of it is permanent. Hang the treatments on a couple of nails or screws and listen to some familiar music. If you like the effect, secure the panel to the wall. If you don't like it, remove the panel. But you'll never know whether you like it or not unless you hear it for yourself.

 

[west10100]

I just completed my acoustic DIY project.
almost similar to sandy FM thread .
Used rockwool covered with foam and cloth on MDF wood panels.
Did 4 corner traps and 10 wall panels.
IT Makes my audio sound beautifully clear.
Total cost
rockwool 3000.
cloth 2000
foam 600
wood 1700
screws, l angles, gun tacker 600
No labour DIY !

 

[john_k_antony]

West,

Thank you very much for the Info. May I know the following details as I am in the process of doing the same.

For side wall absorbers,

1. What is the dimension of each panel? Length x Width x Thickness?
2. From what height from the floor did you place them on the wall?
3. How much air gap did you leave between the panel and the wall behind it? Usually people leave 2-4". I am planning to leave around 2" between the panel and the wall.

For bass traps,

1. What is the dimension of each ? Length x Width x Thickness?
2. Are these traps triangular base or rectangular base?
3. I am planning to build 6" thick triangular panels and place them in the corners.

Thanks,
John.

 

[west10100]

West,

Thank you very much for the Info. May I know the following details as I am in the process of doing the same.

For side wall absorbers,

1. What is the dimension of each panel? Length x Width x Thickness?
2. From what height from the floor did you place them on the wall?
3. How much air gap did you leave between the panel and the wall behind it? Usually people leave 2-4". I am planning to leave around 2" between the panel and the wall.

For bass traps,

1. What is the dimension of each ? Length x Width x Thickness?
2. Are these traps triangular base or rectangular base?
3. I am planning to build 6" thick triangular panels and place them in the corners.

Thanks,
John.

HI John
I didnt go for foam after reading various acoustic forums and threads , ended up with rockwool
SIDE PANELS
1. 1mt x 0.6 mt panel this is the standard rockwool slab size. I layered 2 slabs 2 inch each , total 4 inch thickness. You can see this video to understand that the rockwool is on top of wood panel and not inside. This gave me an additional 2 inch ( wood width) away from the wall. https://www.youtube.com/watch?v=iyYUpkpL0gw

2. 40 cm from floor to cover my front speakers
3. 2 to 3 inch from wall with eye hooks on wood, hung on to wall with wire connecting eyehooks .
BASS TRAPS
1. I didnt have much space on either side of my screen. I had to limit my bass traps to 30 cm width ( half the width of rockwool ) Used 6 inches for bass traps from top to bottom in two/three pieces ( back wall/front wall).
each piece 1 mt height
2. I didnt go for triangular ones. JUst cut the panels in two half 30 cm width and stacked them one above another ( 3 )
3. If you have space, triangular slabs should sound better

Regards
Arun

 

[sash]

west, can you pls post some pictures of the panels and of the room?

 

[john_k_antony]

Arun,

Thank you very much for the details. I am also doing very similar to what you have.

My absorber panels are 2'x4'x4". Each panel would be made with 19mm Plywood frame with 2 layers of Anutone Synth PF topped by 20mm Anutone Strand SS. This panel will be covered with black color acoustically transparent cotton cloth. The panel will be placed 16" (40cm) above floor level. I am planning to leave 1" gap between the panel and the wall and these panels will be hung from the wall and not permanently fixed.

For bass traps, the plan is to make 6" deep plywood frame using 19mm plywood and fill each frame with 3 layers of 2" Anutone Synth and cover with fabric. These panels would be placed in all the 4 corners of the room from floor to ceiling. I am not going with the triangular one as I have read that the performance vs cost ratio is not that significant compared to rectangular panels kept at the corner.

Thanks,
John.

 

[west10100]

Arun,

Thank you very much for the details. I am also doing very similar to what you have.

My absorber panels are 2'x4'x4". Each panel would be made with 19mm Plywood frame with 2 layers of Anutone Synth PF topped by 20mm Anutone Strand SS. This panel will be covered with black color acoustically transparent cotton cloth. The panel will be placed 16" (40cm) above floor level. I am planning to leave 1" gap between the panel and the wall and these panels will be hung from the wall and not permanently fixed.

For bass traps, the plan is to make 6" deep plywood frame using 19mm plywood and fill each frame with 3 layers of 2" Anutone Synth and cover with fabric. These panels would be placed in all the 4 corners of the room from floor to ceiling. I am not going with the triangular one as I have read that the performance vs cost ratio is not that significant compared to rectangular panels kept at the corner.

Thanks,
John.

true, ethan winer the reputed acoustic expert too says there wont be a big difference between triangular fully filled corners vs rectangular slabs with air gap.

 

[west10100]

Few of my DIY acoustics

 

[west10100]

Few of my DIY acoustics