Suspended ceiling angled or convex curved????

[Kaj]

Hi,
I have a thread ongoing in construction see link;
http://www.johnlsayers.com/phpBB2/posti ... st&p=54751

The room is intended to work well as a live room and rehearsal room, so there are no mix position to concider.

We have come to the stage where we intend to install angled soft fibre board suspended from the ceiling, to minimise the flutter between Ceiling and floor. We will put some 50mm OC 703 type of insulation above. The excisting ceiling is made of 12mm MDF painted.
The spotlights in the ceiling can be moved as required to accomodate the boards.
I plan to hang them in 11 degrees angle and alter as per attached pics.

Question:
I need help or suggestions about the two options I see or even better some different suggestions from anyone with experience of this type of treatment.

Cheers

[Ro]

Both options will deflect sound (not diffuse). The bended panes will deflect in different directions, so might be a better option. Altho I'd suggest absorbing instead of deflecting. (replace the ceiling hanged boards with wool for example) You'll prolly have a laminated floor (?) and reflections should be absorbed somehow, so ceiling absorption is the way to go.

BUT, I'd measure the room prior to installing any (mid/high) absorbent materials. Your "basstraps" will also absorb some mid/high.

There's always a change you absorb to much and make a room too "dead"

[Kaj]

Thanks Ro,
I have pretty lot of Helmholtz resonators target lo mid to high mid, 9 sections 1,2x2,4m, I will install two more high frequency absorbers on the walls 1,2x1,2m. I agree that absorb are a good way to go but, as you mention it is a risk of kill the ambience by making the room too dead. I have used the RT60 calculator and are about 0,5 sec equal on all frequencies last time I ran the calculator, and I used wood floor in the calculation. So I will have a look on the curved option with insulation added.
I will run the RT 60 ASAP, I have 6,9 m2 of surface 705 (bass trap and slot surfaces) and >3,4 m2 of 703.

Do you think that it is a good idea to configure as BMP 1, I mean to mirror the tilt of the boards each side of the wooden support beam?

Cheers

[kendale]

Aloha,

Happy New Year, Kaj. Glad to see the progress you've been making.

We have come to the stage where we intend to install angled soft fibre board suspended from the ceiling, to minimise the flutter between Ceiling and floor.

Perhaps you might consider going with the absorber treatment as you have lots of reflective surfaces with your slat wall & floor?

Keep up the good work,

Aloha

[Ro]

Thanks Ro,
I have pretty lot of Helmholtz resonators target lo mid to high mid, 9 sections 1,2x2,4m, I will install two more high frequency absorbers on the walls 1,2x1,2m. I agree that absorb are a good way to go but, as you mention it is a risk of kill the ambience by making the room too dead. I have used the RT60 calculator and are about 0,5 sec equal on all frequencies last time I ran the calculator, and I used wood floor in the calculation. So I will have a look on the curved option with insulation added.
I will run the RT 60 ASAP, I have 6,9 m2 of surface 705 (bass trap and slot surfaces) and >3,4 m2 of 703.

Still, measurements with your EARS and a mic/speaker setup is advised.

Do you think that it is a good idea to configure as BMP 1, I mean to mirror the tilt of the boards each side of the wooden support beam?

IF your going with bended wood panels, I'd make a "whole" bend (in your pic the panels are half bended). The panels will also do some low-end (depends on the depth of the panels) resonating trapping. When adding wool it'll stop the panels from ringing too much and also absorb mid/highs.

(I'm not an "expert" on acoustics)

[Kaj]

Thanks Ro and Kendale
Kendale, heard about some kind of a earth rumble in your area. Had a small one in Russia where I work, never fell out of bed so it was a gentle one, I live on the other side of the ridge most likely.

Perhaps you might consider going with the absorber treatment as you have lots of reflective surfaces with your slat wall & floor?

I have considered over and over again, but are scared to kill the sound. It is a live room! RT 60 already 0,5 seconds, in a thin walled room. I have an idea that I can redirect the flutter towards the traps and absorbers to treat there! I believe/hope I have enought treatment to deal with the modes of the room except the flutter, but are worried to over kill in treatment as I have very thin walls and the low end are not a problem, it comes in nearby 218-223 Hz and harmonics on that (tested before I extended with two more absorbers), thats what my Helmholtz absorbers are adjusted to specifically target this frequencies (flutter?) on the northern wall. Mission Impossible??

IF your going with bended wood panels, I'd make a "whole" bend (in your pic the panels are half bended). The panels will also do some low-end (depends on the depth of the panels) resonating trapping. When adding wool it'll stop the panels from ringing too much and also absorb mid/highs.

Ro
They are not half bended/curved, they are tilted lowered in one end to deflect sound towards an wall absorber, and I will have the option to angle the boards as they will be adjustible to tilt from +/- 15 deg to aim them towards the absorbing wall receiving deflected sound from a 90 deg center line. And I also expect the mid high absorbtion from the coctail of options of insulation material I can choose adding from. I'm not an expert in acoustics too, so what will be the next move?, I have not started yet to cut or assemble, but are very close to start the frame work for the boards. Anyone with an opinion are welcome. Still respect your point Ro and I think I cover it WRT angle not absorbtion.

i have added a third HF adsorber on the west wall that is easy to convert to a Lo Mid absorber, that will come during fine tuning. See the empty frame in attachment.

Thanks and cheers

[knightfly]

If your ceiling height isn't too low, you might consider some thin plywood poly's - all it takes is a way to pull the two sides of a full sheet of plywood together to form a convex curve, then hang them from the ceiling so they'd hold water if you poured it into them. Won't kill highs, WILL give a type of diffusion, WILL kill flutter, can be stained to look better than soft sound board... Steve

[Kaj]

We have completed the ceiling boards almost to 100%, see link;
http://www.johnlsayers.com/phpBB2/viewt ... 5164#55164

Cheers

[Kaj]

Hi,
I pushed myself a bit harder to complete the ceiling boards and installed them. the boys will put in the new floor today.

I have glued the sound fibre board to the fram and used gypsum screws. I also mounted a cross joist(?) in the center of the width of the board to secure the radious stays in shape.

I have delibrerately choosed to not fill all boards, need to measure the room acoustics before I know what is required to be done. The boards increased the reverbation time so the defection is working, the sound warmed up abit.

And here are more pics, and construction progress.
http://www.johnlsayers.com/phpBB2/viewt ... 5190#55190

Cheers