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Title: Acoustic Plaster instead of Acoustic Panels
Post by: Edward Petruescu on July 10, 2018, 03:01:00 pm
Does anyone have any experience with acoustic plaster? My church is in the process of constructing a new building and I want to come up with ideas about how to deaden in reverb. My fellow church members have a prejudice about acoustic panels since it looks "ugly" so I was looking into a system that would work instead. There is two type that I have seen on the internet, 1) for the ceiling, it gets a layer of mineral fiberboard that is then plastered over 2) a plaster mix with fiberglass that is sprayed on all surfaces up to an inch and a half thick. The first option is supposed to absorb like 90% of sound while the second 80%.<<something like that.
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Tom Burgess on July 10, 2018, 03:09:06 pm
Does anyone have any experience with acoustic plaster? My church is in the process of constructing a new building and I want to come up with ideas about how to deaden in reverb. My fellow church members have a prejudice about acoustic panels since it looks "ugly" so I was looking into a system that would work instead. There is two type that I have seen on the internet, 1) for the ceiling, it gets a layer of mineral fiberboard that is then plastered over 2) a plaster mix with fiberglass that is sprayed on all surfaces up to an inch and a half thick. The first option is supposed to absorb like 90% of sound while the second 80%.<<something like that.
At what frequency?  Do these products have a lab-verified NRC?
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: David Allred on July 10, 2018, 03:27:08 pm
Does anyone have any experience with acoustic plaster? My church is in the process of constructing a new building and I want to come up with ideas about how to deaden in reverb. My fellow church members have a prejudice about acoustic panels since it looks "ugly" so I was looking into a system that would work instead. There is two type that I have seen on the internet, 1) for the ceiling, it gets a layer of mineral fiberboard that is then plastered over 2) a plaster mix with fiberglass that is sprayed on all surfaces up to an inch and a half thick. The first option is supposed to absorb like 90% of sound while the second 80%.<<something like that.

So then you have to install reflective panels to liven the room?
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Keith Broughton on July 11, 2018, 07:16:20 am
As Tom mentioned, at what frequency?
You need to know how much sound is absorbed or reflected at various frequency bands.
Here is some info I found...
https://www.baswana.com/technical-data (https://www.baswana.com/technical-data)
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Erik Jerde on July 11, 2018, 10:21:24 am
You should contract an acoustician to work with the architect to get the acoustic design of the space done properly.  Itís important to hire someone who understands the style of worship youíre doing (classical vs contemporary vs modern vs ultra modern etc).  They can work with you on helping to choose the right treatments and building materials/methods.  They will also be a big help in bringing people along on the acoustic panel issue.  They arenít all big and ugly.

Honestly, if you donít get the acoustics of the room right in the design phase then youíre just burning money and being terrible stewards by building anything.  Itís many times easier (and cheaper) to fix an acoustic problem before the structure is built.  Be good stewards and hire an expert to help you get it right.
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Fred Dorado on July 11, 2018, 12:46:14 pm
as far as ugly -

Go to Spoonflower.com you can get custom printed materials, while all will have some impact on sound, they have some that are fairly thin and be more acoustically transparent than others.
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Edward Petruescu on July 24, 2018, 04:02:11 pm
At what frequency?  Do these products have a lab-verified NRC?

When I made the post I didn't look at specific products since I just found out that something like that existed. The product that I'm looking at right now is USG Acoustical Plaster Finish for cost reasons. We will be putting up drywall and the thickest this product can be on drywall is 1/2".

Data:
125: 0.55, 250: 0.20, 500: 0.28, 1000: 0.65, 2000: 0.88, 4000: 0.86, NRC 0.50
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Edward Petruescu on July 24, 2018, 04:05:47 pm
So then you have to install reflective panels to liven the room?

I mainly want to target stage noise and the reflections from the speaker and not all of it either. We remodeled a multipurpose room so that we can use it as we build the main building and the acoustics in it are absolutely horrible due to the design of the building and the same issues will be in the new building too.
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Edward Petruescu on July 24, 2018, 04:11:54 pm
You should contract an acoustician to work with the architect to get the acoustic design of the space done properly.  Itís important to hire someone who understands the style of worship youíre doing (classical vs contemporary vs modern vs ultra modern etc).  They can work with you on helping to choose the right treatments and building materials/methods.  They will also be a big help in bringing people along on the acoustic panel issue.  They arenít all big and ugly.

Honestly, if you donít get the acoustics of the room right in the design phase then youíre just burning money and being terrible stewards by building anything.  Itís many times easier (and cheaper) to fix an acoustic problem before the structure is built.  Be good stewards and hire an expert to help you get it right.

I was trying to learn to use an open source building acoustic software that I found but I will look into contacting an acoustician since it is a tough subject. Problem with having a church full of contractors is that there isn't much planning involved since they apply their residential construction knowledge and experience to a commercial space(though I'm working on changing that).
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Edward Petruescu on July 24, 2018, 04:13:50 pm
as far as ugly -

Go to Spoonflower.com you can get custom printed materials, while all will have some impact on sound, they have some that are fairly thin and be more acoustically transparent than others.

I was thinking of getting fabric with bible verses on it in order to make it feel more like decoration.
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Edward Petruescu on July 24, 2018, 04:38:45 pm
I apologize for the late responses, I was expecting to receive an email whenever someone responded but I never did. Its also has been a while since I stopped visiting this forum daily (about a year or so).
The current building we are in is a vaulted multipurpose room with semi-smooth plaster finish which reflects sound as if it a school gym. The new building is pretty close, design-wise, to the multi-purpose room and I want to be proactive with fixing it. I was thinking of using USG acoustical plaster for the ceiling in order to reduce general floor noise (and speaker) and I'm not sure if there is a plaster that can go on the wall or not. Most of what I've seen go on the ceiling except for a company in the UK that sprays plaster on the walls too. The wall that I want to use the acoustic treatment on is the front wall (when looking at the stage).

What are your guys' experiences with systems from USG or Baswana?
I'm going to order some samples tomorrow from these two companies but if you guys have any other recommendations I'm open to it.
Do any of you know of someone in the Sacramento CA area that consults with stuff like this? I'd gladly pay for some consulting though it is out of my wallets capability to hire a company to actually do any acoustic treatments.

The attached picture is the building that I mocked up in a 3d program. (Sanctuary area of 40' x 40' and stage of 10-12' by 40'). The knee wall at the stage is just to hide the wires/monitors/screens/stuff. (my current plan)
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Mike Caldwell on July 24, 2018, 05:50:11 pm
I apologize for the late responses, I was expecting to receive an email whenever someone responded but I never did. Its also has been a while since I stopped visiting this forum daily (about a year or so).


For some reason that feature has not worked for a year or more.

With stage monitors and a full band your room will at least need some sound absorption on the back wall.

Are you going to use acoustic drums or electronic?
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Edward Petruescu on July 24, 2018, 06:36:15 pm
For some reason that feature has not worked for a year or more.

With stage monitors and a full band your room will at least need some sound absorption on the back wall.

Are you going to use acoustic drums or electronic?

I was thinking the same thing. Acoustic plaster would be nice on the back wall but I'm not sure if it can be done. Otherwise, I was thinking of installing sound absorption panels along the walls of the stage.

The drums will be acoustic and I will definitely need to get an enclosure/shield for them (not enough room in our current building)
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Mike Caldwell on July 24, 2018, 08:20:03 pm
I was thinking the same thing. Acoustic plaster would be nice on the back wall but I'm not sure if it can be done. Otherwise, I was thinking of installing sound absorption panels along the walls of the stage.

The drums will be acoustic and I will definitely need to get an enclosure/shield for them (not enough room in our current building)

In a room of that size go with electronic drums, the "drums are too loud" problem will be instantly taken care of and no one in congregation will care or notice about the drum "sound" other than it's not too loud. The stage will also look better without a big fish bowl in the middle of it.

 
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: David Allred on July 24, 2018, 09:42:48 pm


Data:
125: 0.55, 250: 0.20, 500: 0.28, 1000: 0.65, 2000: 0.88, 4000: 0.86, NRC 0.50
Is the 125 number a typo?  Seems out of place, unless it is because of the density and mass of it  The 250 and 500 number are pretty bad, and the 1000 is not great.  Seems like this product would suck the presence  out of the room and still have too  much energy  in the 250 to 1k region that it is weak in addressing.
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Edward Petruescu on July 25, 2018, 01:50:36 am
In a room of that size go with electronic drums, the "drums are too loud" problem will be instantly taken care of and no one in congregation will care or notice about the drum "sound" other than it's not too loud. The stage will also look better without a big fish bowl in the middle of it.

We currently have an acoustic drum set and no one complains about their loudness though I have an issue with it being picked up by the singers' mic (mainly the symbols). I would prefer an electric one for sure and I've never actually thought about how it would look with a drum shield.
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Edward Petruescu on July 25, 2018, 02:02:14 am
Is the 125 number a typo?  Seems out of place, unless it is because of the density and mass of it  The 250 and 500 number are pretty bad, and the 1000 is not great.  Seems like this product would suck the presence  out of the room and still have too  much energy  in the 250 to 1k region that it is weak in addressing.

It is not a typo. Since I have no scale of what the numbers mean, I thought the numbers looked pretty good, but now that you pointed it out, they look to be quite lacking.  It can only be a half inch thick on drywall but over a stronger surface, it can be up to an inch thick.
 @ 1"
125: 0.04, 250: 0.22, 500: 0.60, 1000: 1.01, 2000: 1.07, 4000: 1.00, NRC: 0.75

BASWA has a lot better numbers but they require a mineral fiber board to be attached to the drywall than with plaster applied over it. It would definitely be a better system and I'll look into the cost difference.
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: David Allred on July 26, 2018, 11:46:18 am
It is not a typo. Since I have no scale of what the numbers mean, I thought the numbers looked pretty good, but now that you pointed it out, they look to be quite lacking.  It can only be a half inch thick on drywall but over a stronger surface, it can be up to an inch thick.
 @ 1"
125: 0.04, 250: 0.22, 500: 0.60, 1000: 1.01, 2000: 1.07, 4000: 1.00, NRC: 0.75

BASWA has a lot better numbers but they require a mineral fiber board to be attached to the drywall than with plaster applied over it. It would definitely be a better system and I'll look into the cost difference.

My explanation is not correct, but it might help you interpret the numbers.
Compare to ratios and percentages. 
In the above, 1000hz vs 500hz is 10:6 or 500hz  absorption is 60% effective compared to 1000hz effectiveness.
Again, not actually true... but at a rating of 1.00 (really good) it is like an open window is letting sound at that frequency out of the room never to be hear from again.  The window is proportionally closed when it comes to other frequencies.  In this case 78% closed at 250hz, 40% closed at 500hz.
As a wall covering, it is self-limiting in that it is not a spreadable effect like panels.  Though I suppose you could use it like crown molding to wrap the room so that it looks structural.  The height would be determined by the rooms need.  This still doesn't address the problem of if the room's problem resonances don't line up with effectiveness of the coating material.

Good luck.
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Kevin Maxwell on July 26, 2018, 01:13:23 pm
I have worked with an acoustics company that has done some rather big projects. So I am sure that they are WAY out of your price range. I have been shocked at how much of a difference it can make to have someone who really knows what they are doing. I was in a house (being built for a Billionaire) and the entrance-way/foyer (if that is what it is called) was probably bigger then my house. I expected it to sound like an echo chamber and very lively (usually annoyingly so) but it didnít at all and there wasnít any visible treatment that I could see. To have them involved before the plans are made is really the way to do it. But someone who is good can steer you in the right direction to make the changes that will work for how the room will be used.

In the long run a good acoustic expert can save you money. Because it will cost a lot to do it wrong and then try to correct it with the sound system and then redo everything all over again. Or have to live with the problems, which if they are bad enough will affect attendance.

Notice I said how the room is used. I cringe every time someone says the acoustics in this room are very good or very bad. That statement is incomplete, there needs to be a qualifier. It may be very bad for amplified music but it may be great for a pipe organ. Or it may be great for an orchestra but not again amplified music. But the hard part may be that you will want the amplified music to be tamed (I hope you understand what that means) but you probably want the congregational singing to be a little bit more lively.
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Jason Glass on July 26, 2018, 02:19:47 pm
Looking at your photo, it appears that you would get much more cost effective results by preventing sound from reaching troublesome reflective surfaces and by breaking up wavefronts than you will coating those surfaces in "stuff". What do I mean? I mean placing acoustic absorbent and diffusion panels on the flat back wall, and most importantly installing multiple acoustic "clouds" and heavy fabric vertical baffles throughout the ceiling peak.

https://www.google.com/search?source=hp&ei=BxBaW_nCGI7ctQXp1qKQDw&q=acoustic+cloud&oq=acoustic+cloud&gs_l=mobile-gws-wiz-hp.3..0l5.5044.5330..6750...0.0...102.205.2j1......0....1.......0..0i131.4lfHKA7CWnA

(https://uploads.tapatalk-cdn.com/20180726/fb1c486f99bcde7b6d205363893e6536.jpg)(https://uploads.tapatalk-cdn.com/20180726/337fc9447e498d65ba26bb8e4c02b7a1.jpg)

Sent from my SM-G950U using Tapatalk

Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: lindsay Dean on July 26, 2018, 03:39:16 pm
Without an acoustical engineer,
and without a sound company designing a system for you .
Some main things would be,
 number one, controlling the sound generated from the stage.
 That is going with in ear monitors ,
electronic drums or control booth for the drums ,
 guitar and keyboard amps excetera being located in another room  back stage
and micd.
point source boxes  aimed and tuned
 You will have to pay a real company to tune an implement the mains
no way out of that one.
and this would stop a lot of the energy from being started in the first place
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Taylor Phillips on July 27, 2018, 11:56:33 pm
Looking at the picture, I can say I've definitely been in similarly shaped rooms which were completely dead acoustically.  They all just had soft carpet flooring and either acoustic tile or "popcorn" ceilings.    I'm not sure how acoustic plaster compares to these measures, but they were too dead in my opinion.   

I seem to be a bit on the unorthodox side of things in the sound debate sometimes since I don't see a need to completely eliminate neither natural reverb nor stage noise for amplified music, and prefer open acoustic drum kits.  My experience is that a "controlled" stage, rather than a nearly silent one, with a somewhat live acoustic in the main room creates a more engaging environment for the congregation and can even compensate for some of the shortcomings of an inexperienced sound technician (though that is very dependent on having cooperative musicians).  A dead room with a near-silent stage requires top-notch equipment and operators for the band to sound good, and even then people in the congregation might not enjoy singing along that much.  The silent stage and dead acoustics is the usual situation at my friend's church, but for a special worship night for which he asked me to sound, we used an acoustic drum kit (mic'd, no shield) in lieu of their electronic one, put a bass cabinet on stage (no subs in their PA), and I fixed the connection to their reverb unit.  I was a bit disappointed in the sound due to the lack of subs to put the kick drum through and not having as much control of the bass as I like, but everyone from the church was simply astounded at how much better the band sounded that night. 
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Edward Petruescu on July 31, 2018, 02:16:37 pm
As Tom mentioned, at what frequency?
You need to know how much sound is absorbed or reflected at various frequency bands.
Here is some info I found...
https://www.baswana.com/technical-data (https://www.baswana.com/technical-data)

I just received a quote for the average cost per square foot and it is way out of my budget at $40 per square foot at 1000 square feet. I was thinking of just having it above the stage but that would be $22,000 ($45 per square foot at 500 square feet since it costs more per square foot when you buy less). Way more cost effective to just make/buy sound absorption panels
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Jeremy Young on July 31, 2018, 06:40:07 pm
I just received a quote for the average cost per square foot and it is way out of my budget at $40 per 1000 square feet. I was thinking of just having it above the stage but that would be $22,000 ($45 per square foot at 500 square feet). Way more cost effective to just make/buy sound absorption panels

No part of that math makes any sense to me, can you double check your numbers?  At $40 per 1,000 square feet, for a 500 square foot area you'd be paying $22.50

At $45 per square foot, 500 square feet would cost $22,500

Those are very different numbers.  So are 40 and 45.... just saying. 

I wish I had the acoustical knowledge to contribute to this thread in some other way than proofing math, but hey, helping where I can.
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Edward Petruescu on August 02, 2018, 08:29:00 pm
No part of that math makes any sense to me, can you double check your numbers?  At $40 per 1,000 square feet, for a 500 square foot area you'd be paying $22.50

At $45 per square foot, 500 square feet would cost $22,500

Those are very different numbers.  So are 40 and 45.... just saying. 

I wish I had the acoustical knowledge to contribute to this thread in some other way than proofing math, but hey, helping where I can.

I corrected it. It costs more when you buy less.
Title: Re: Acoustic Plaster instead of Acoustic Panels
Post by: Kevin Maxwell on August 02, 2018, 11:03:40 pm
This company has some interesting things that they do with Out-rounds. https://www.jdbsound.com/ they will even work with your church and show them how to build what they need. I have no personal experience with them.

I will caution you about the results of not knowing what you are doing with a quote from their website ďYes, anyone can put panels on a wall and change the sound of a room but when you visit most churches that have such panels, you soon discover that all they did was trade one set of problems for another and the quality of worship was not improved at all.  Such acoustical fixes do improve the performance of a sound system slightly but falls way short of what was expected and the congregational singing is often worse than before.  If you are going to spend a lot of money on room acoustics, why not get everything fixed at the same time.  It doesnít cost any extra and it never has.Ē

It can save you a lot to do it right from the start. But my personal feeling about acoustics companies and sound systems is have the acousticians deal with the acoustics and someone else deal with the sound. There may be people that can do both but I havenít found them yet. I am not saying that the company I linked to canít do both, but I donít know if they can. The giveaway to me is sometimes the weird speaker and sound system solutions they come up with. 

Donít forget if you hire someone to do a job be sure there is a performance guarantee in the contract.