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Post by Hexspa on Sept 16, 2020 20:00:21 GMT
I don't know. I didn't look at the calculator and it looks like you're adjusting the air gap. Not sure what it means by 'rigid backing' and 'air gap'. I can understand 'air gap' but 'rigid backing' usually negates any air gap.
All I can say is that, when I went from 2" to 4", I noticed an improvement in the range you're looking to treat. The standard practice is 4" minimum for music. Do what you want but I wouldn't use 2" if I didn't absolutely have to.
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Post by rock on Sept 16, 2020 21:47:42 GMT
Regarding the calculated curve VS actual measurements: If you have some way of easily adjusting your gap, with perhaps a linked chain and hook arrangement, you can then experiment with different gap dimensions to measure what actually works the best for you.
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jared
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Post by jared on Sept 17, 2020 7:43:33 GMT
thanks Hexpa and Rock. rock, unfortunately the current 1.5cm fiberglass ceiling tiles are hooked with a chain and special bolt to the top of the ceiling. There is an 18cm air gap between these tiles and the concrete ceiling above. I will have to redo the entire ceiling if I want to move these up and down. @hexpa, I am going to go with your suggestion and try the 10cm (4") of Rockwool above the current ceiling tiles, leaving an 8cm air gap. When I tick the boxes "random incidence" on the calculator, your suggestion of 10cm rockwool fairs better. In my original calculation, I was not ticking the box "random incidence". Please see below. Thanks once again guys.
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Deleted
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Post by Deleted on Sept 17, 2020 11:42:26 GMT
You are not really interested in random incidence.
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Post by rock on Sept 17, 2020 13:07:17 GMT
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jared
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Post by jared on Sept 17, 2020 13:41:59 GMT
Thank you pasim and rock. Much appreciated
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Post by Hexspa on Sept 17, 2020 18:57:55 GMT
What's random incidence about? If it's about the directionality of the panel then I'd say that random incidence is relevant. As many of you know, axial modes and RFZ points are not all that the absorption is working on. We have all kinds of modes and secondary reflections that come from probably every angle. Frictional absorbers are incident-dependent and they're probably working off-axis most of the time. This is why we consider it a bonus to have the sides of a panel exposed giving you an increase in surface area up to 25%.
Pasim, you have one of the best rooms I've seen here - though I know you've changed it a bit. It seems like you're not for 4". Why is that?
Jared, if you cover the whole ceiling with 4", you'll get a substantial reduction in ringing and reflective effects. I just can't, in good conscience, recommend 2" thickness of any material for any reason other than an attempt to improve speech clarity. To me, it seems long since established that 4" is the minimum thickness anyone would want for music. I can virtually guarantee that you'll be happy with the improvement with 4" but perhaps not know what you're missing - or, technically, not missing - if you use 2".
Just my half-baked opinion!
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jared
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Post by jared on Sept 17, 2020 20:33:39 GMT
Thanks for that Hexspa.
So just to clarify, what is the “random incidence” box for and should I tick it or now?
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Deleted
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Post by Deleted on Sept 18, 2020 7:15:49 GMT
If its ceiling after all, so yeah it's not totally normal incidence, but in small rooms there isn't really random incidence because no true reverberant field. So it would be like half-way between.
"You don't need a diffuse field to get non-normal incidence... you just need the sound to arrive at an angle significantly less than 90°... That can happen in a small room." (Quoted text, from person I would trust)
I'm all for thick absorption, you ideally should go 60cm-100cm all across the room, it definitely makes the room appear smaller. But as you go deeper, you need low density and lower flow resistivity. You can easily see that by playin' with that calculator.
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Deleted
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Post by Deleted on Sept 18, 2020 7:30:32 GMT
Yes, I had good room "on paper" that's just one part of it. Never liked how it sounded.
I've actually been into couple "pro studios" that had not so good sounding control room(at least for my ears), like that I could not easily achieve good mixes..
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Post by Hexspa on Sept 19, 2020 17:52:54 GMT
I don't know exactly how the calculator results translate into an actual room - I never factored it in. All I know is that more absorption is generally better than less and that includes thickness and coverage in square feet.
Another thing is I strongly encourage anyone who's treating their first room to not overthink it. Just buy as much absorption as possible and cover your corners and RFZ with thick panels. After that, you can start asking questions about 2" vs 4", mineral wool vs glass wool, fluffy vs rigid, Helmholz resonators and the like.
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Deleted
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Post by Deleted on Sept 20, 2020 7:08:34 GMT
If you just want guanranteed good room that highly will work. Just hire a professional acoustician who designs and makes the plans for your room, and then build according to that. Maybe not cheap, but not overly expensive either.
Because they know what works, they've failed more times than you have even thought about room treatment.
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Post by Hexspa on Sept 21, 2020 19:09:34 GMT
He's already said that it's hard to find a good acoustician in the jungle where he is.
I believe he can make a great room with a bit of trial and error and trust.
It's not that hard: walls create problems - absorption eliminates walls.
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Deleted
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Post by Deleted on Sept 22, 2020 6:03:15 GMT
You don't even need to personally meet the acoustician, there are plenty good ones that never visit the build. Doing the work purely via internet and clients measurements.
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jared
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Post by jared on Sept 22, 2020 8:03:38 GMT
Thank you. I managed to get an appointment with Barry Rudolph who lectures on acoustics in the US (lynnard skynard producer). He gave some really good tips but I think the info that you all provided is priceless and will get me 99% the way there. Thank you all once again!
Will report back when I put in the treatment next week
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