tomas
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Posts: 22
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Post by tomas on May 13, 2016 16:43:32 GMT
Hello again,
I have a thread about my room here already but would like to ask this question separately as it might apply to more rooms not just mine. Excuse me if it's not ok doing this separately and please merge my two threads.
So the question is what's better to use a absorber or diffuser over the listening and/or recording position. I mean when it comes to low ceiling (and by low ceiling I mean around 7') it's always about absorbers. But let's think about it this way (and please correct me if I am wrong): When drums are recorded in low ceiling room there're always with overheads. What's an issue here is that the ceiling is reflecting sound too quickly. Frequencies that are reflected are mostly those over 300Hz right? (Frequencies below 300Hz behave physically in a different way.) So what I am thinking is to reflect them other way than back from where they came - aka back to microphones (overheads). In that case I would have to use diffuser right? And what a rigid absorber does it absorb mostly bass and reflect some of the highs (is this statement correct?). So where did I do the mistake? Is it really diffuser > absorber when it comes to ceiling?
Thanks! Tomas.
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Post by Ethan Winer on May 13, 2016 19:50:27 GMT
I never did extensive tests because of the difficulty, but I can give you some general advice. If the ceiling is very low, I think you'll do better with absorption than with diffusion. I'd say you need at least 2-3 feet between overhead microphones and a diffuser above. My partner Doug's studio has a low ceiling, about 7.5 feet, and he gets a great drum sound. The ceiling is fully absorbent, with 12 inches of fluffy fiberglass above fabric. There are diffusers directly behind the drums, but they're still several feet away from the microphones. I just finished this video shot there, and he recorded the drums in the same corner you see here:
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tomas
New Member
Posts: 22
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Post by tomas on May 13, 2016 21:36:27 GMT
Well I can't afford adding 12" to my ceiling for sure. Would it help putting 2" rigid mineral wool (with 2" air gap above) in shape of a triangle to do both absorption and diffusion? Or the best would be just add as much mineral wool on the ceiling as I can afford? Well I am somewhere between 7' and 7.5' with my ceiling.
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Post by Hexspa on May 14, 2016 7:54:37 GMT
Diffusion and absorption are usually divided up into separate instances with the exception of the Real Traps diffuser. 2" of mineral wool will have one effect while 12" of fluffy will have another. It's up to you to decide which kind of effect you want or need given your specific constraints.
Something will be better than nothing but Ethan just told you his professional solution to his own partner's studio - it's probably your best bet.
Apache!
-m
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tomas
New Member
Posts: 22
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Post by tomas on May 14, 2016 13:34:47 GMT
Diffusion and absorption are usually divided up into separate instances with the exception of the Real Traps diffuser. 2" of mineral wool will have one effect while 12" of fluffy will have another. It's up to you to decide which kind of effect you want or need given your specific constraints. Something will be better than nothing but Ethan just told you his professional solution to his own partner's studio - it's probably your best bet. Apache! -m yea but I can't loose 12" from my rooms height. It has already low ceiling (somewhere between 7' and 7.5'), so I can't go to 6', it's too low. I'll probably add 2" rigid absorber with 2" air gap above. I am just asking whether it's better than using diffuser. Or whether it's useful to make a triangle kind of diffuser from mineral wool.
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Post by Rock on May 14, 2016 15:00:27 GMT
I don't know what a "triangle diffusor from mineral wool" is but I would say go with an absorber "cloud" over the drums. For that matter, over anywhere you're micing, especially vocals when the singer is standing (and the mic is relatively close to the ceiling.
I have a 7' 6" ceiling over the drums and I have 4" mineral wool suspended 4" down. You have less height so yeah, you'll need to make adjustments. If you can afford it, you'll get slightly better LF absorption with 4" right up against the ceiling as opposed to 2" with 2" gap. I think of the gap as kind of a "cheat" or "trick" to make the absorber "look" thicker to the sound waves you're absorbing. Of course it really works but you can look at it that way keeping in mind there is nothing wrong with an absorber flush against a wall or ceiling, it's just that you get more LF performance for your money by using a gap.
Your absorber will absorb all high and mid frequencies down the low freq which is determined by the thickness. Thicker = lower. As long as you leave the front side (and back too) un-faced, that is without foil, paper, or plastic, it will absorb mid and high freqs fine. The facing should be used to enhance low freq absorption for corner bass traps where mid and high reflections will not matter. But for a recording set up, you'll want absorption at all freqs., so use un-faced.
Cheers, Rock
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Post by Rock on May 14, 2016 15:06:23 GMT
Hey Ethan,
Cool video! Great playing and sound! APACHE!
Cheers, Rock
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Post by Ethan Winer on May 14, 2016 16:18:45 GMT
Well I can't afford adding 12" to my ceiling for sure. Would it help putting 2" rigid mineral wool (with 2" air gap above) in shape of a triangle to do both absorption and diffusion? Or the best would be just add as much mineral wool on the ceiling as I can afford? Well I am somewhere between 7' and 7.5' with my ceiling. Doug's studio is in his basement and the ceiling had been 12-inch joists. So he just stuffed the joists and stapled fabric to their bottoms rather than add sheet rock as most people do in a finished basement. If you already have a finished ceiling then of course you can't add that much thickness. So sure, rigid fiberglass two inches thick with another two inches of air is as good as four inches thick. I wouldn't bother with triangles, though I suggest using FRK type material around the perimeter to get more bass trapping. In fact, better than 2+2 is 4+2 or even 4+4 around the perimeter. That lowers the ceiling by eight inches, but only for the outer two feet border around the room. --Ethan
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tomas
New Member
Posts: 22
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Post by tomas on May 14, 2016 20:24:58 GMT
Well I can't afford adding 12" to my ceiling for sure. Would it help putting 2" rigid mineral wool (with 2" air gap above) in shape of a triangle to do both absorption and diffusion? Or the best would be just add as much mineral wool on the ceiling as I can afford? Well I am somewhere between 7' and 7.5' with my ceiling. Doug's studio is in his basement and the ceiling had been 12-inch joists. So he just stuffed the joists and stapled fabric to their bottoms rather than add sheet rock as most people do in a finished basement. If you already have a finished ceiling then of course you can't add that much thickness. So sure, rigid fiberglass two inches thick with another two inches of air is as good as four inches thick. I wouldn't bother with triangles, though I suggest using FRK type material around the perimeter to get more bass trapping. In fact, better than 2+2 is 4+2 or even 4+4 around the perimeter. That lowers the ceiling by eight inches, but only for the outer two feet border around the room. --Ethan Thanks Ethan! Do you think you can specify how does FRK affect sound by wrapping around perimeter? I know it gets some bass when faced into room, bot what about perimeter of 2" rigid board? isn't it too small area? so if the board is 2"x23"x47" the perimeter is just 280 square inches (speaking about single one). When I put frk on my corner traps which are 20"x80" facing the room, I'll get 1600 square inches covered with frk (also speaking about one single corner). So why just so small area like you said?
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Post by Ethan Winer on May 16, 2016 15:42:01 GMT
A "perimeter" goes all around a room. So a decent size room could have 18 panels 2x4 feet just around the border, which is 144 square feet of surface. Ignore the 8 tiles in the middle, but this shows what I mean:
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Post by Hexspa on May 17, 2016 5:44:54 GMT
You mean.. oh ok acoustics is confusing
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Post by Hexspa on May 17, 2016 10:57:58 GMT
For a room that's primarily for mixing, and with the exception of close rear walls, is extensive ceiling and other flat-surface absorption in the back half really beneficial?
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Post by Hexspa on May 17, 2016 11:00:08 GMT
Ok I guess it is extensively treated by not unduly so. Is liveness the reason you left spaces? Again would you just go crazy and use membrane traps if you were so inclined?
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Post by Ethan Winer on May 17, 2016 16:59:24 GMT
Yes, the rear wall behind you is a source of damaging reflections at all frequencies, but the side walls in the rear may be less important. This is why we measure, to find out. My home studio is in one very large room, so it doesn't need to be as dead as a bedroom size space to be accurate and sound good.
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Post by Hexspa on May 18, 2016 4:34:02 GMT
Yes, the rear wall behind you is a source of damaging reflections at all frequencies, but the side walls in the rear may be less important. This is why we measure, to find out. My home studio is in one very large room, so it doesn't need to be as dead as a bedroom size space to be accurate and sound good. *firing up fuzzmeasure* Roger.
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