Hi Spaceboy, long time since last?
I will try to clarify again in a bit more depth, reasons behind decisions about design, I have qouted similar questions about these boards and will not only answer your question, but Ro as well and any other that want to know why???
Here are a qoute from my earlier posts on this thread;
What is the bad thing(s) to use Soundboard for what I intend to use it for , (anything good with Soundboards VS polys at all?). I have seen One of the legend Bruce Swedien's personal friend in Sweden (Björn Asplind) design of a studio with this sound board as deflecting/diffusion devices suspended from the ceiling . Background of Björn;
Björn wrote an Sound engineering book for the Swedish musicians/sound engineers in the 80ies , and I had him as a mentor and we used Michael Jacksons Thriller, in Multi track version (thanks to Bruce giving a copy away ) during my Sound engineer training, It might be the old school from 80's that used soundboards and not plywood??
Background Note:
Björn was having the designer of Vivaldi Studios and Bohus studio as instructor/trainer during his start in the acoustic/recording swamp. Åke Eldsäter was involved in this training as well as far as i have been able to find out on other forums. One of the most famous groups ABBA used Studio Bohus and Åke Eldsäter are to be found on some of their records as well as the cream of the Swedish musicians as sound engineer, he is one of the best in Sweden. He recorded our first record in Studio Bohus 1982 so I have an Idea of his skill. I can not for sure say where the slanted soft boards used in the studio Björn was leading the project came from, but the studio sounded fine, not dead as the previous at the same location. He used the same system for floating the floor as for Vivaldi studios, so I can only guess he got the idea from Vivali Studios.
Your question;
Your clouds brings a question to mind so I'll just ask it here. Flutter echo is created from having two parallel walls and your convex cloud sill reduce that. My question is, is the flutter only a problem from perpendicular to both parallel walls from the original sound source?
And from Ro as well.
I'm still not sure on those ceiling panels. Although they're convex styled it would still leave an amount of energy scattered through the room (at least there's some diffusion going on) But we'll know for sure when your back with "hearing" tests/results, eh!
Ok, I poured up a single malt and getting ready for reply to you. All at the same time I would assume.
The design of these soft boards in the ceiling, are only there to deflect the sound to stop flutter between perpendicular Floor and Ceiling, nothing more nothing less. I have designed them to be adjustible in view of angle and pack some insulation on top of them. I will during the fine tuning try with different amount and type of insulation on top of them, currently only 4 are filled to 50% with similar to OC703 95mm thick. I can hear clearly that the very high end are more damped, and the reverbation increased after installing them. But the flutter around 210 Hz allmost dissapeared after installation, need to adjust my helmholtz to more around 210Hz will be verified during measurement, we can only wait until that day, and I will not keep them if they are doing bad to the sound. We can in 5 minutes remove them and test acoustics and re install with different configurations i.e. angle and type of filling test again, but I will not do this if all is ok from start. I might do this test just to verify (Not prove) if they are doing anything good or bad.
I understand that building helmholtz or other kind of traps around the whole building will absorbing problem frequences, might be a good way to go, but if I say that my trausers stays up with belt only, why put suspenders as well?
The room we have treated have very thin wall construction and are not showing any big problem soo far in the LF.
Note.
There are noise leaking in from the traffic outside approx 150m away. If I would go for taking care of that would I have to build a room in the room, but the joist would not cope.
To add more mass to the walls, was not practical as the studs where OC600mm and some of the walls built on 2x3 studs, would be much weight with three layers of gypsum board as there are only a 12mm MDF on walls and ceiling. Floor MDF 28mm. End Note
So with this given starting point, I had no other options as I can see than try to get the room as it was to sound as good as possible with a reasonable amount of work and material to be used, a bit driven by budget and a bit driven by common sence. To not add more mass reduced the need of Low range trapping, a cost save. I used all frequencies for the room modes to decide the two first helmholtz absorbers and the 200-230hz as target for the last two absorbers on north wall, I might slope the Ceiling panels to defect more sound towards those absorbers in hope that they will take care of some of it.
Hope I have not bored you with my logic and plan behind decisions made in the past? I have not exhausted my my memory of ideas and plans behind this design but, think I have give you enough to start to ask more if any clarifying are required.
Thanks for your questions, I do enjoy discussions about this subject and other music/acoustic/construction topics as well, and I'm NOT an expert in acoustics, but have picked up little here and there. Please keep asking, question or comment as you feel approriate, I learn from that as well.
Cheers
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