This is probably an one reply thread but I need to ask the an obvious question to me. In my experience and talking with various other people first reflection control is one of the fundamental factors in home 'hifi'. This has got me thinking does this first reflection control carry over to church PA systems. Most churches are not designed for live sound and usually have a high reverb time and problem frequencies (such as 300hz).
If this speculation carries, I am curious what materials would be used to control it? I know there is a lot materials but since it is a public area needs needs to not only pass the WAF but has to be aesthetically pleasing. The only quick and nice looking method I can think of is a heavy velvet, or similar 18oz, drapes drawn half closed or more and it would be approximately 3 inches off the wall. According to
this material is effective above 250 hz. However, this method is nice and pleasing to the eye I do not know what local fire codes might say about it.
Good idea?
If this speculation carries, I am curious what materials would be used to control it? I know there is a lot materials but since it is a public area needs needs to not only pass the WAF but has to be aesthetically pleasing. The only quick and nice looking method I can think of is a heavy velvet, or similar 18oz, drapes drawn half closed or more and it would be approximately 3 inches off the wall. According to
HTML:
http://www.sae.edu/reference_material/pages/Coefficient%20Chart.htmGood idea?
so just what sort of issue are you trying to resolve with this form of acoustic treatment?
RT 60 constants are a huge factor when it comes to intelligibility in large rooms.
RT 60 constants are a huge factor when it comes to intelligibility in large rooms.
I am wondering if first reflections are a serious consideration in a PA system. I do not know what the reverb time is but it 'colouring' the sound of male speech in particular. I have applied a 100 hz high pass, - 6 200 hz cut, and a +3 3khz boost and that helped. The reverb after this eq is still unpleasant and I am hoping that a first reflection treatment would help.
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As I spend much of my life in large hotel ballrooms and convention centers, I can say "yes, first reflections matter." We have many of the same acoustic problems as found in churches.
Heavy drape can help in the frequency ranges you mention, but you might want to look at putting Ultra Touch insulation (made by Bonded Logic) behind it. It's made from recycled denim. It seems to work well in lower frequency ranges and would do a lot more there than just drape.
As Turk points out, it's not just the first reflections. Rooms can be boomy for a lot of reasons. Treatment is often complex and expensive. But you have to start somewhere.
Heavy drape can help in the frequency ranges you mention, but you might want to look at putting Ultra Touch insulation (made by Bonded Logic) behind it. It's made from recycled denim. It seems to work well in lower frequency ranges and would do a lot more there than just drape.
As Turk points out, it's not just the first reflections. Rooms can be boomy for a lot of reasons. Treatment is often complex and expensive. But you have to start somewhere.
what sort of speakers are in use here and where are they placed?.
close attention to directivity and placement can help but aren't the end all.
are we talking a mic'ed vocal(live) or reproduction(playback of recorded material)
mic type and placement relative to the source are also going to be big factors in getting good (or decent) results in a largely reverberant environment.
treating the room is surely going to help but 8 out of 10 times architectural solutions result in a capital cost that far outweighs most budgets or pass the WAF criteria.
close attention to directivity and placement can help but aren't the end all.
are we talking a mic'ed vocal(live) or reproduction(playback of recorded material)
mic type and placement relative to the source are also going to be big factors in getting good (or decent) results in a largely reverberant environment.
treating the room is surely going to help but 8 out of 10 times architectural solutions result in a capital cost that far outweighs most budgets or pass the WAF criteria.
Below is a quick sketch of the church.
http://s24.postimg.org/5i1j6f1k5/Church_Page_1.jpg
All absorption material is begins at 5 feet from ground and continues to ceiling (approx. 10 - 12 feet.).
Mains mounted at ~8.5 feet. No toe in and directly mounted to wall. The mains are 'retro' big box EV's.
Announcement mic is centre of lower stage. The amount of reverb in the room makes it so that no monitor mix is made for the mic. The mic is a sennhesier e 845.
http://s24.postimg.org/5i1j6f1k5/Church_Page_1.jpg
All absorption material is begins at 5 feet from ground and continues to ceiling (approx. 10 - 12 feet.).
Mains mounted at ~8.5 feet. No toe in and directly mounted to wall. The mains are 'retro' big box EV's.
Announcement mic is centre of lower stage. The amount of reverb in the room makes it so that no monitor mix is made for the mic. The mic is a sennhesier e 845.
Thanks for the drawing. From that I would guess the major 1st reflections are from the floor and ceiling. Do you have a way to measure impulse response?
Unfortunately, I do not have a usb sound card to use REW, or equivalent, is their another method?
what is the overall ceiling height?
getting the speakers away from the walls would be step one to reducing early reflections.
if ceiling height permits (but from what you just told me the boxes aren't good candidates for rigging EV SH1502?)i would "fly" them side by side toed out so they behave more like a point source and aim them down at the seating area. short of that columns because of the narrow vertical coverage would be a potential asset in not letting excess energy excite the reverb in the room.
getting the speakers away from the walls would be step one to reducing early reflections.
if ceiling height permits (but from what you just told me the boxes aren't good candidates for rigging EV SH1502?)i would "fly" them side by side toed out so they behave more like a point source and aim them down at the seating area. short of that columns because of the narrow vertical coverage would be a potential asset in not letting excess energy excite the reverb in the room.
The ceiling is ~12ft. I believe the mains to be EV SH-1512 ER's (very similar to the EV SH1502). It is a short ceiling but I will check on Sunday what the height actually is (might be 16 instead 12 feet, still quite short).
I am advocating the mains to be replaced with a pair of Community ENTASYS line arrays or similar (I have a soft spot for line arrays).
The Mains are mounted to the wall on a 'diy' 45 degree wood bracket. If the mains where in better condition and had a taller ceiling I would prefer a 'flying' setup.
http://www.communitypro.com/productlist/102-entasys
I am advocating the mains to be replaced with a pair of Community ENTASYS line arrays or similar (I have a soft spot for line arrays).
The Mains are mounted to the wall on a 'diy' 45 degree wood bracket. If the mains where in better condition and had a taller ceiling I would prefer a 'flying' setup.
http://www.communitypro.com/productlist/102-entasys
Sorry, I didn't make the mental connection between column and line array. However, I do feel that is the best option.
in the days of old many a church has equipped with homebrew column speakers consisting of five drivers with a selection of 8 and 4 or 8 and 16 ohm drivers (along with 70v x-formers)wired to create what was know as a shaded volume array for the express purpose of pattern control.
yes moving the location of the main speakers is by far the biggest step toward eliminating your "early reflection" problem. (which if i'm not mistaken; their current position puts them behind most of your open mic's.moving up or out will probably allow for more gain before feedback and a greater degree of latitude for EQing) and yes acoustical treatment can definitely have an impact but as mentioned this is highly dependant on budget and acceptance.
My church has the exact same shape. We have our D&B Audiotechnik mains and subs flying right above your middle blue rectangle.
Sorry for the wait but things move slowly. The general agreement within the praise team is that the mains are a priority replacement. They do not seem concerned with sound treatment until the mains are installed.
It would seem that from further eq experimentation that 2-5 khz is a real problem. Aside from lead vocal, all channels have at least 6 db cut in this range and it still 'edgy' and harsh. I need a sit down and get a budget going.
It would seem that from further eq experimentation that 2-5 khz is a real problem. Aside from lead vocal, all channels have at least 6 db cut in this range and it still 'edgy' and harsh. I need a sit down and get a budget going.
so is that replacement as well as relocation cuz new speakers in the same locations will still leave you in acoustic treatment territory...
if 2-5 Khz is bad news on the cheap disassemble the horn check the drivers (if they're bad/damaged/cracked surrounds or just dirt encrusted it might kickstart budget talks!! hopefully!)
i'm not a fan of those horns especially with open mic's in front (no gain/headroom before feedback lousy pattern control so without crossover tailoring that's pretty much how they sound with the passives (most have pass resistors in the x-overs that get smoked by feedback) bi amping these boxes would be a marginal improvement.
if 2-5 Khz is bad news on the cheap disassemble the horn check the drivers (if they're bad/damaged/cracked surrounds or just dirt encrusted it might kickstart budget talks!! hopefully!)
i'm not a fan of those horns especially with open mic's in front (no gain/headroom before feedback lousy pattern control so without crossover tailoring that's pretty much how they sound with the passives (most have pass resistors in the x-overs that get smoked by feedback) bi amping these boxes would be a marginal improvement.
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