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Church and H.O.W. Forums for HOW Sound and AV - Your Displayed Name Must Be Your Real Full Name To Post In The Church and HOW Forums => Church Sound => Topic started by: Arnold B. Krueger on May 02, 2011, 08:33:56 am

Title: Amazing (to me) Room Acoustics Success Story
Post by: Arnold B. Krueger on May 02, 2011, 08:33:56 am
We've been living for about 4 weeks with the results of our first attempt at improving the acoustics of our sanctuary.  The room is 45 x 120 x 27. We put up sound absorbers made by a member, based on a single 2" layer of 705 high density fiberglass spaced about 4 inches away from the front of our balcony,  in a lightweight wooden frame and covered on the front with grille cloth. Total area covered is  under 180 square feet. Compare that to 145,800 square feet of walls, floor and ceiling.

Benefits:
Sound at mix position more strongly resembles the sound in middle of room.
People on the platform hear cleaner sound from their stage monitors.
Some members who relied on our hearing assistance system now say that they can hear fine without it.

Absence of Problems:
No complaints that we spoiled the sound of the pipe organ, congregational singing, etc.
Few people have visually noticed that there was a change.
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Brian Ehlers on May 02, 2011, 06:35:35 pm
Congratulations!  It's amazing you were so successful with only 180 sq. ft. of treatment.  That shows you had a VERY specific problem.

I bet you had to fight like a dog to get approval to do this.  Which means it took a lot of guts on your part to tackle the project.  Of course, there was almost zero chance it would make things worse -- but would it be worth it?  It's not easy to stick your neck out like that.  Good job.
 
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Brad Weber on May 02, 2011, 09:36:39 pm
Glad to hear it worked so well for you!
 
I always get a bit worried when I hear about people using the online calculators from acoustical panel manufacturers or basing acoustical treatments on some very basic calculation of reverberation time as it's a matter of not just the surface area you have of different materials but also of putting the right materials in the right places.  Sometimes less material used judiciously can be more effective than more material placed without much thought.
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Arnold B. Krueger on May 04, 2011, 06:40:12 am
Congratulations!  It's amazing you were so successful with only 180 sq. ft. of treatment.  That shows you had a VERY specific problem.

I bet you had to fight like a dog to get approval to do this.

You've been reading my posts here!  Yes, the church boards are loathe to do anything at all, especially make a change that might be real and noticable.

Quote
Which means it took a lot of guts on your part to tackle the project.

With these guys, I'm beyond guts. They managed to turn the knife several times, though. The wouldn't let me officially recommend them. They had to hire a consultant. He and I talked and came up with this. They wouldn't let me design them, a board member who was an architect designed something with the fiberglass (He knows not about 703 or 705) firmly attached to new 3/4" ply with no space behind the fiberglass. He knows not about the benefits of spacing absorbers, but he is one of *them*.  They wouldn't let me build them, either. They found another church member who I secretly  convinced to change the design pretty dramatically. This worked out pretty well except that he felt that they would be improved by putting an arched piece of pegboard that bowed out about 2 inches in the middle. I showed him papers and formulas that said that regular pegboard has so few holes that it is just a piece of board, but he knows better than science. Since this didn't cause much loss of depth, I finally rolled over.

Quote
Of course, there was almost zero chance it would make things worse

The board was so concerned that they would ruin the sound of the organ that they demanded that the panels be designed so that they could quickly be removed. This of course made them more complicated and further delayed things.

Quote
-- but would it be worth it?  It's not easy to stick your neck out like that.  Good job.

One nice thing about having no credibility with your church board is that you can't hurt your credibility any further! ;-)
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Arnold B. Krueger on May 04, 2011, 06:51:18 am
Glad to hear it worked so well for you!
 
I always get a bit worried when I hear about people using the online calculators from acoustical panel manufacturers or basing acoustical treatments on some very basic calculation of reverberation time as it's a matter of not just the surface area you have of different materials but also of putting the right materials in the right places.  Sometimes less material used judiciously can be more effective than more material placed without much thought.

Excellent point. The online calculators I've seen to date treat all areas the same. 

I've known for almost 50 years that this particular area was the major problem with the room. I first heard it talking back to me when I was 16 and sang with the adult choir. Believe it or not I've been complaining about it since then but almost nobody heard the same thing.

When it became clear that we might be able to actually do something with the room. I bought a toy cap pistol and set up my Microtrack and a couple of mics (1 omni, one cardioid) in the middle of the platform and did some tests. The impulse from the cap pistol timed out to exactly coincide with the front of the balcony, and its reflection was far and away the biggest thing in the room.  It was thus time to stake what was left of my life on fixing it first.

We're meeting today with the consultant to plot out our next move. Everybody on the inside knows that we had our one golden opportunity and probably did pretty well with it. We know that from here on in we'll have to cover far more area to make a similar difference.
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Dan Andrews on May 05, 2011, 09:15:25 am
Hi Arnold,

That sounds very interesting, and well done.

Any chance of some photos?  I would love to see what the construction of the sound material is like.

All the Best, Dan Andrews
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Arnold B. Krueger on May 05, 2011, 10:33:35 am
Hi Arnold,

That sounds very interesting, and well done.

Any chance of some photos?  I would love to see what the construction of the sound material is like.

All the Best, Dan Andrews


Since I didn't do the work and the panels are all in place. no pix of the construction and sound material is likely.

But, it is as simple as apple pie and can be summarized as approximate 4' x 6' x 6" wooden frames covered with light bown Guilford firepoof grille cloth material. Inside, there is a 2' thick surface of Dow Corning 705 that fills the frame's front just behind the grille cloth.

Since the fiberglass panels are 2' x 4' x 2", they are pieced together to cover the entire area. This was faciliated by cross braces that coincided with the lines where the pieces came together.

There is an approximate 4" empty space behind the fiberglass sheets, except for a piece of 1/4" pegboard materail  with a slight curve to it so that the middle of the pegboard is about 2" into the empty space, and its top and bottom edges are at the back.

I think that the grilled coth and the pegboard are gratuitous. Just about any cloth would do if it was fireproofed, which is pretty easy to do. After all, if the grille cloth absorbs sound before it reaches the 705, it still gets absorbed, right? ;-)

The frames fit between decorative upright posts on the front of the balcony.  One surprise was that none of the panels are identical or even symmetrical. The decorative posts were all spaced differently, as if by eye.  The front of the balcony is about 6' high and 45 feet wide. The total ceiling height is about 27' so only a fraction of the back wall off the church was actually covered.

It seems like diffusion due to the sloped pews in the balcony broke up many of the reflections from the back wall behind the seats in the balcony.  The pews on the flat main floor seem to have had a similar effect on the reflections from the back wall below the balcony.  The media booth's front surface is about 4' high, rus about half the width of the room, and may have some mitigating effect on the reflections off the back wall below the balcony.
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Brian Ehlers on May 05, 2011, 01:36:01 pm
One surprise was that none of the panels are identical or even symmetrical. The decorative posts were all spaced differently, as if by eye.
Don't you just love working on old churches?   :)

Quote
It seems like diffusion due to the sloped pews in the balcony broke up many of the reflections from the back wall behind the seats in the balcony.  The pews on the flat main floor seem to have had a similar effect on the reflections from the back wall below the balcony.
Regularly spaced reflections can have a really bizarre effect on the sound.  I wonder if you could pick out the individual reflections from each row of pews when you performed your cap-gun experiment?

The exterior wall of the building in which I work consists of corrugated steel with a small, vertical notch maybe every 8 inches.  Several hundred yards away, at an oblique angle, is an industrial building with what sounds like rocks falling down a conveyer.  As I walk across the parking lot, I can hear the impulse response of each rock reflect acoustically off my building.  The small notches seem to reflect a very narrow range of frequencies, so there is that high-pitched tone.  But each notch reflects the sound at a different time, giving the sound a zipper-like effect of lower frequency.  It's totally bizarre.  Since the dimensions of church pews are larger, any similar effect would be at lower frequencies.  But I've always wondered how much of the clutter of sound I hear in our sanctuary is that  coming from empty pews.  It would be worst, of course, for those on stage.
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Dan Andrews on May 06, 2011, 09:09:05 am
Since I didn't do the work and the panels are all in place. no pix of the construction and sound material is likely.

But, it is as simple as apple pie and can be summarized as approximate 4' x 6' x 6" wooden frames covered with light bown Guilford firepoof grille cloth material. Inside, there is a 2' thick surface of Dow Corning 705  that fills the frame's front just behind the grille cloth.

Since the fiberglass panels are 2' x 4' x 2", they are pieced together to cover the entire area. This was faciliated by cross braces that coincided with the lines where the pieces came together.

There is an approximate 4" empty space behind the fiberglass sheets, except for a piece of 1/4" pegboard materail  with a slight curve to it so that the middle of the pegboard is about 2" into the empty space, and its top and bottom edges are at the back.

I think that the grilled coth and the pegboard are gratuitous. Just about any cloth would do if it was fireproofed, which is pretty easy to do. After all, if the grille cloth absorbs sound before it reaches the 705, it still gets absorbed, right? ;-)

The frames fit between decorative upright posts on the front of the balcony.  One surprise was that none of the panels are identical or even symmetrical. The decorative posts were all spaced differently, as if by eye.  The front of the balcony is about 6' high and 45 feet wide. The total ceiling height is about 27' so only a fraction of the back wall off the church was actually covered.

It seems like diffusion due to the sloped pews in the balcony broke up many of the reflections from the back wall behind the seats in the balcony.  The pews on the flat main floor seem to have had a similar effect on the reflections from the back wall below the balcony.  The media booth's front surface is about 4' high, rus about half the width of the room, and may have some mitigating effect on the reflections off the back wall below the balcony.

Thanks Arnold,

I am trying to imagine what you have described, but when you say "there is a 2' thick surface of Dow Corning 705"  I am thinking you meant a 2" thick surface, is that right? 

I haven't ever heard of Dow Corning 705, is that fibreglass batts used to insulate house walls with, or something else?

Thanks again.

All the Best, Dan
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Brad Weber on May 07, 2011, 01:15:57 am
I am trying to imagine what you have described, but when you say "there is a 2' thick surface of Dow Corning 705"  I am thinking you meant a 2" thick surface, is that right? 

I haven't ever heard of Dow Corning 705, is that fibreglass batts used to insulate house walls with, or something else?
I think it was a typo and Arnold was referring to this, http://commercial.owenscorning.com/products/pipe/fiberglas-700-series-insulation/ (http://commercial.owenscorning.com/products/pipe/fiberglas-700-series-insulation/).  The 700 series is compressed fiberglass board and the different models in the series (701, 703, 704, 705 and 707) relate to different densities (the last digit in the model number is roughly the density in pounds per cubic foot).  They're readily available in 1" or 2" thicknesses and either unfaced or with an FRK (Foil Reinforced Kraft) or ASJ (All Service Jacket) facing.
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Dan Andrews on May 07, 2011, 02:58:15 am
Thanks Brad,

That's what I though, and thanks for the web site info.

All the Best Dan
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Arnold B. Krueger on May 09, 2011, 07:58:14 am
I think it was a typo and Arnold was referring to this, http://commercial.owenscorning.com/products/pipe/fiberglas-700-series-insulation/ (http://commercial.owenscorning.com/products/pipe/fiberglas-700-series-insulation/).  The 700 series is compressed fiberglass board and the different models in the series (701, 703, 704, 705 and 707) relate to different densities (the last digit in the model number is roughly the density in pounds per cubic foot).  They're readily available in 1" or 2" thicknesses and either unfaced or with an FRK (Foil Reinforced Kraft) or ASJ (All Service Jacket) facing.

Exactly, and the unfaced products are what you want for just about any acoustics application.  Johns Manville and others have competitive products, and other products made from mineral wool have similar acoustical properties. If it is 2" thick, composed of fine fibers, and its density is about 5 pounds per cubic foot (which makes it like a board) then it probably does about the same thing to sound waves. Absorbers can also be made out of cotton or polyester, but those alternatives seem to be more costly. 

Higher density products seem to absorb lower frequencies better, which is why the materials used for acoustical treatments are generally far denser than the ones made for thermally insulating walls and ceilings. A friend of mine who does lab tests on these things says that it is very hard to pack these kinds of fibrous materials so tighly that they turn into reflectors.

So, if I had made my sound absorbers out of 2" thick fiberglass batts of the kind used as thermal wall insulation, the absorbtivity at say 100 Hz would have been far less and the quality of the results would have been audibly diminished.
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Greg_Cameron on May 10, 2011, 03:03:26 pm
I read an article recently that stated the denim based "eco insulation" works better for sound panels than any of the fiberglass stuff. Anyone have any input on that?

Greg

http://www.bondedlogic.com/ultratouch-cotton.htm
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Arnold B. Krueger on May 13, 2011, 06:22:49 am
I read an article recently that stated the denim based "eco insulation" works better for sound panels than any of the fiberglass stuff. Anyone have any input on that?

http://www.bondedlogic.com/ultratouch-cotton.htm

My friends who pursue this kind of thing in the lab tell me that there is no magic related to fiberglass versus rock wool versus polyester versus cotton versus whatever. Given a certain kind of fine fiber and a certain packing density, they absorb sound by means of the same basic physical process and the results are pretty much the same.

What is different is how it feels to work with the various materials.

My house is insulated with rock wool, and the attic of our sanctuary at church is insulated with loose fiberglass. In either case wise people wear particulate masks, cover their bodies with long pants and long sleeves, and change their clothes and bathe within minutes of walking off the job. I think that rock wool is a bit nastier than fiberglass, but the difference is the difference between very ugly and very, very ugly.

Polyester and cotton batts can be messy, but they aren't nearly as nasty to work with a fiberglass or rock wool. I guess that people who work in factories with lots of cotton fiber dust in the air for decades can get a kind of lung disease,  but casual work with sound absorbers doesn't usually involve that sort of thing.

Sound absorbants are interesting when you consider that unpainted cinder block is about 1/3 as absorbant as high density fiberglass of similar area and thickness. Paint it and close the pores and its almost as nasty-sounding as glass or tile. However, split concrete blocks with a coarse surface can sound pretty good as diffusers.

Diffusion while expensive is not to be underestimated. The broadcasts of the recent royal wedding sounded pretty good to me  despite the fact that the majority of the absorbtion in the room was people.

Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Andre Vare on May 13, 2011, 02:59:53 pm
I read an article recently that stated the denim based "eco insulation" works better for sound panels than any of the fiberglass stuff. Anyone have any input on that?

Greg

http://www.bondedlogic.com/ultratouch-cotton.htm

For thicknesses up to 4" all the materials are similar at appropriate densities.  Ultratouch appears to have significantly higher gas flow resisitivity, making it worse for applications it is thicker than 4".

Andre
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Brad Weber on May 13, 2011, 05:06:22 pm
Diffusion while expensive is not to be underestimated. The broadcasts of the recent royal wedding sounded pretty good to me  despite the fact that the majority of the absorbtion in the room was people.
It can be expensive to add diffusion after the fact, especially for some types of diffusers, however it may not necessarily as expensive to incorporate some forms of diffusion into the initial design and construction of a space.
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: chris harwood on May 14, 2011, 01:34:35 am
I treated my control room in my studio and took before and after measurements.  The measurements were meaningless, as the results were stunning, that I didn't need to look at graphs and numbers.  I used Owens Corning 703 and made 4" deep absorbers and pretty much randomly placed them on the walls, attempting to hit the most obvious refection points (using a mirror against the wall and wherever I could see my speakers from my mix position, put an absorber.  I also straddled the corners with 4" material, 2 feet wide, from floor to ceiling.

I spent a good day making nice looking bass traps and about $350 in materials.  I would have spent $20k if I knew it would have improved imaging, tightened up the bass, and eliminated a pile of peaks and dips across the spectrum, as good as it did.

HIGHLY recommended.  I'd bet you could spend $5k in a typical 50x75 foot sanctuary, and have similar results.  It aint rocket science as some might have you believe.  Just do it "right"  !!
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Brad Weber on May 14, 2011, 07:27:57 am
I treated my control room in my studio and took before and after measurements.  The measurements were meaningless, as the results were stunning, that I didn't need to look at graphs and numbers.  I used Owens Corning 703 and made 4" deep absorbers and pretty much randomly placed them on the walls, attempting to hit the most obvious refection points (using a mirror against the wall and wherever I could see my speakers from my mix position, put an absorber.  I also straddled the corners with 4" material, 2 feet wide, from floor to ceiling.

I spent a good day making nice looking bass traps and about $350 in materials.  I would have spent $20k if I knew it would have improved imaging, tightened up the bass, and eliminated a pile of peaks and dips across the spectrum, as good as it did.

HIGHLY recommended.  I'd bet you could spend $5k in a typical 50x75 foot sanctuary, and have similar results.  It aint rocket science as some might have you believe.  Just do it "right"  !!
I keep saying this, but while home studio acoustics and large room acoustics share many commonalities, there are also many differences.  Some are technical, e.g. tending to be modal versus rebverberant controlled and the time relationships between reflections and the direct sound, while others are functional, e.g. looking at a small and specific listener position versus a large listener area, and code driven.  Maybe you can indeed make big changes for a relatively small investment, but there are good reasons that you'd usually approach the audio in a studio and Sanctuary quite differently and similar logic also applies to acoustics.
 
Also, acoustics for Sanctuaries and similar spaces is not limited to adding finishes after the fact, it should not only extend into aspects such as room dimensions and room shape but can also encompass aspects such as mechanical system noise and vibration control and interior and/or exterior sound isolation.
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: chris harwood on May 15, 2011, 01:28:40 am
I keep saying this, but while home studio acoustics and large room acoustics share many commonalities, there are also many differences.  Some are technical, e.g. tending to be modal versus rebverberant controlled and the time relationships between reflections and the direct sound, while others are functional, e.g. looking at a small and specific listener position versus a large listener area, and code driven.  Maybe you can indeed make big changes for a relatively small investment, but there are good reasons that you'd usually approach the audio in a studio and Sanctuary quite differently and similar logic also applies to acoustics.
 
Also, acoustics for Sanctuaries and similar spaces is not limited to adding finishes after the fact, it should not only extend into aspects such as room dimensions and room shape but can also encompass aspects such as mechanical system noise and vibration control and interior and/or exterior sound isolation.

I can't disagree but would hope anyone with a head on their shoulders would realize all that.  Obviously doing it right from the beginning during a build is MUCH better than a "fix". I was only wanting to illustrate a good end result, even though for all the differences you went to the effort to detail.

I have been in sanctuaries with fiberglass plastered on the walls... and looking good, that worked VERY well.  Even as a "fix".
Can't also disagree that once spaces get to a certain size, diffusion should come into play.  After all, you don't want your sanctuary to sound like a "library" and completely isolate your congregation.  That's just weird acoustics.

edit...oops spelling...watch out..maybe more!!
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Brad Weber on May 16, 2011, 07:12:09 am
I can't disagree but would hope anyone with a head on their shoulders would realize all that.  Obviously doing it right from the beginning during a build is MUCH better than a "fix". I was only wanting to illustrate a good end result, even though for all the differences you went to the effort to detail.
I appreciate what you were trying to do and hope others do as well.  However, I've been surprised how many people dealing with larger spaces, including churches, seem to get ideas for DIY acoustics directly from the numerous home studio and home theatre resources that are so readily available.  And also how many think only of room finishes when thinking of acoustics without considering how acoustics can extend into aspects of the space design such as room shaping, room volume, space planning, HVAC system design, etc.  It's not a church but I'm currently working on the acoustics for a $350+ million building and the vast majority of my time is being spent on HVAC system noise and vibration control, interior and exterior sound isolation, space adjacencies and so on.
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: chris harwood on May 16, 2011, 08:39:05 pm
I appreciate what you were trying to do and hope others do as well.  However, I've been surprised how many people dealing with larger spaces, including churches, seem to get ideas for DIY acoustics directly from the numerous home studio and home theatre resources that are so readily available.  And also how many think only of room finishes when thinking of acoustics without considering how acoustics can extend into aspects of the space design such as room shaping, room volume, space planning, HVAC system design, etc.  It's not a church but I'm currently working on the acoustics for a $350+ million building and the vast majority of my time is being spent on HVAC system noise and vibration control, interior and exterior sound isolation, space adjacencies and so on.

Your current job sounds impressive.  Thanks for telling us. 
Like I said, I think most trying to deal with acoustics understand some basic principles, whether they get them from that Winer guy and his bass traps or whether they actually read up on it and study.  I guess trying to contribute in the shadow of your experience really is probably a waste of my time.  I'm sure your finished project will be an example many should aspire to.
Unfortunately, there are too many Kingdom projects that only have 5 grand or less and it IS a fix.  Ripping out existing HVAC systems and putting in the new Binford 5000 hush system isn't typically the first solution. 
Good blessings for your current project.
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Arnold B. Krueger on May 17, 2011, 08:20:42 am
And also how many think only of room finishes when thinking of acoustics without considering how acoustics can extend into aspects of the space design such as room shaping, room volume, space planning, HVAC system design, etc.  It's not a church but I'm currently working on the acoustics for a $350+ million building and the vast majority of my time is being spent on HVAC system noise and vibration control, interior and exterior sound isolation, space adjacencies and so on.

As I do my spring tour of high school auditoriums for the choir/band festival recording season, I see many examples of what you are talking about. Rather nice rooms with a giant wart of a noisy HVAC system are very common. 

I find it interesting that a new auditorium with a flat floor is virtually unheard of for secular-purposed buildings such as schools, but people are still doing it to new churches all of the time, and with a big tradition-loving grin on their faces.
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Steven Tye on May 18, 2011, 01:19:09 am
Hi Arnold - you said that you didn't have any pictures of these getting made or installed, but do you have any of what they look like afterwards?
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Arnold B. Krueger on May 26, 2011, 05:33:29 am
Hi Arnold - you said that you didn't have any pictures of these getting made or installed, but do you have any of what they look like afterwards?

Here are pictures of the front of the church (for reference) and the back of the church including the sound absorbers on the front of the balcony.

(http://home.comcast.net/~arnyk/graphics/ccc_1321ds.jpg)

(http://home.comcast.net/~arnyk/graphics/ccc_003f.jpg)

This is a "before" picture:

(http://home.comcast.net/~arnyk/graphics/ccc02f.jpg)

Note the yellow-green cast from the use of legacy flourescent lights that we used in the days when this picture was taken. The other two pictures are of the room after we upgraded the chandeliers with dimmable CFLs and turned the old fluorescents off most of the time.

The top picture was taken on a sunny day when sunlight dominates. The middle picutre was taken on a darker day when the CFLs provide most of the lighting.
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Brad Weber on May 26, 2011, 06:34:33 am
Looks very nice, very much like they were intended to be there.  Now if we could just get Architects to understand that flat, glass rear walls are not a good idea...
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Arnold B. Krueger on May 26, 2011, 09:36:13 am
Looks very nice, very much like they were intended to be there.  Now if we could just get Architects to understand that flat, glass rear walls are not a good idea...

If the flat glass  was the only problem. We're having sound transmission problems, now that with two services we are running classrooms concurently with worship.

What happens is that one of our largest classrooms, taught by a really nice smart guy who happens to have a very low voice who doesn't like microphones, secretly shares a wall with the sanctuary.  Its not obvious but the balcony is the ceiling to the narthex, and that the back wall of the balcony is the side wall of this teaching room.  What is obvious is that we have some tiny monitors in the narthex that do have a little sound coming out of them. What is not obvious to many is that single pane glass and 1/4" plywood are not soundproof.  Therefore, when sound gets transmitted into the classroom, and quite a bit gets there, only the monitor speakers are blamed.

We've done some experiments and all by themselves, the monitors barely hardly make a tiny little sound in the classroom. But the perception is that turning off the monitors helps a lot. Turning those monitors off and on around the worship parts of the service seems small, but most people in the media booth are really busy during transitions, and particularly all the way through the worship. Besides, the monitors really have no bearing on the problem.

So, we've got two problems. Plenty of mechanical sound transmission, and the perception that the problem is the electronics. Leadership doesn't want to try to inform people of the real truth becase then the people who vociferously complained would have made a mistake, beat up the wrong people for the wrong reason, and generally get mad at the church rather than being mad at one person who isn't formally in leadership.

Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Chris Penny on May 26, 2011, 07:05:51 pm
Can I just say that the rear of your church seem very much the same as the rear of my church (complete with sound booth on the right, rear glass wall and gallery over narthex). Has me thinking about our room now.
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Arnold B. Krueger on May 27, 2011, 04:55:36 am
Can I just say that the rear of your church seem very much the same as the rear of my church (complete with sound booth on the right, rear glass wall and gallery over narthex). Has me thinking about our room now.

I'd bet money that about 1/3 of the alegedly 50,000 churches in the USA fit that mold! I know my oldest son's church in PA fits the mold, except that their media booth is on the other side of the aisle.
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Jonathan Johnson on May 27, 2011, 10:20:54 am
Looks very nice, very much like they were intended to be there.  Now if we could just get Architects to understand that flat, glass rear walls are not a good idea...

Since we can't seem to get architects to understand this -- they are thinking sight lines -- perhaps we can get them to angle the glass downward to reduce the inevitable slap-back to the stage.
Title: Re: Amazing (to me) Room Acoustics Success Story
Post by: Brad Weber on May 27, 2011, 10:51:31 am
Since we can't seem to get architects to understand this -- they are thinking sight lines -- perhaps we can get them to angle the glass downward to reduce the inevitable slap-back to the stage.
For some reason people do seem to focus on the plan perspective and forget working in section and elevation, however if you angle the glass with the top leaning toward the stage then you'd want it to be at a sufficient angle that the reflections won't negatively impact the listeners.  I have been successful in getting some Architects to 'sawtooth' the glass in plan.